User Manual
764
Digital Audio Monitor
(Serial Number B020000 and Above)
070-8811-08
This document supports firmware version 2.1 and
above.
www.tektronix.com
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Warranty
Tektronix warrants that the 764 Digital Audio Monitor will be free
from defects in materials and workmanship for a period of one (1)
year from the date of shipment. If any such product proves defective
during this warranty period, Tektronix, at its option, either will repair
the defective product without charge for parts and labor, or will pro-
vide a replacement in exchange for the defective product.
In order to obtain service under this warranty, Customer must notify
Tektronix of the defect before the expiration of the warranty period
and make suitable arrangements for the performance of service. Cus-
tomer shall be responsible for packaging and shipping the defective
product to the service center designated by Tektronix, with shipping
charges prepaid. Tektronix shall pay for the return of the product to
Customer if the shipment is to a location within the country in which
the Tektronix service center is located. Customer shall be responsible
for paying all shipping charges, duties, taxes, and any other charges
for products returned to any other locations.
This warranty shall not apply to any defect, failure or damage caused
by improper use or improper or inadequate maintenance and care.
Tektronix shall not be obligated to furnish service under this warran-
ty a) to repair damage resulting from attempts by personnel other
than Tektronix representatives to install, repair or service the prod-
uct; b) to repair damage resulting from improper use or connection to
incompatible equipment; c) to repair any damage or malfunction
caused by the use of non-Tektronix supplies; or d) to service a prod-
uct that has been modified or integrated with other products when
the effect of such modification or integration increases the time or
difficulty of servicing the product.
This warranty is given by Tektronix with respect to this product
in lieu of any other warranties, expressed or implied. Tektronix
and its vendors disclaim any implied warranties of merchantabil-
ity or fitness for a particular purpose. Tektronix’ responsibility to
repair or replace defective products is the sole and exclusive rem-
edy provided to the customer for breach of this warranty. Tektro-
nix and its vendors will not be liable for any indirect, special,
incidental, or consequential damages irrespective of whether
Tektronix or the vendor has advance notice of the possibility of
such damages.
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Table of Contents
General Safety Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
xi
This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
xi
Contacting Tektronix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xii
Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mechanical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Connecting the 764 to Your System . . . . . . . . . . . . . . . . . . . .
(1) Digital Audio Inputs and Loop-Throughs . . . . . . . . .
(2) Time Code Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(3) Reference Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(4) VGA Video Output . . . . . . . . . . . . . . . . . . . . . . . . . . .
(5) RS-232 Communications Port . . . . . . . . . . . . . . . . . .
(6) Optional Serial Video Loop-Through . . . . . . . . . . . . .
Headphones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supplying Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Power Up and Configuration . . . . . . . . . . . . . . . . . . . .
1
1
1
2
3
5
5
5
6
7
7
8
9
Operating Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Monitoring an Audio Program with the Audio View . . . .
Session Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Monitoring the Ancillary Data . . . . . . . . . . . . . . . . . . . . .
Other Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front-panel Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Level Meters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuring the Level Meters . . . . . . . . . . . . . . . . . . . . . .
Sum and Difference Bars . . . . . . . . . . . . . . . . . . . . . . . . .
The Phase Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Lissajous Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Correlation Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AGC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Session Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
13
13
14
15
16
16
18
22
25
26
27
27
28
29
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Table of Contents
Features of the Session Display . . . . . . . . . . . . . . . . . . . . .
29
30
34
37
39
40
40
40
41
Session Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Session Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Channel Status View . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The User Data View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Saving and Restoring Setups . . . . . . . . . . . . . . . . . . . . . . . . . .
Saving a Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Restoring a Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Editing a Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Level Meters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Meter Ballistics and Alignment Levels . . . . . . . . . . . . . . .
In-Bar Warning Messages . . . . . . . . . . . . . . . . . . . . . . . . .
Correlation Meter Algorithm . . . . . . . . . . . . . . . . . . . . . . . . .
Selecting Headphone Channels . . . . . . . . . . . . . . . . . . . . . . . .
Submenus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Level Meters Submenu . . . . . . . . . . . . . . . . . . . . . . .
The De-emphasis Submenu . . . . . . . . . . . . . . . . . . . . . . . .
The Phase Display Submenu . . . . . . . . . . . . . . . . . . . . . . .
Headphones Submenu . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input Submenu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Time Code Submenu . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Serial Port Submenu . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Save Setups Submenu . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Restore Setups Submenu . . . . . . . . . . . . . . . . . . . . . . . . . .
Screen Saver Submenu . . . . . . . . . . . . . . . . . . . . . . . . . . .
Service Submenu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Using the RS-232 Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cable Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Communication Examples . . . . . . . . . . . . . . . . . . . . . . . .
Outputting a Session Report . . . . . . . . . . . . . . . . . . . . . . .
Remote Control Commands . . . . . . . . . . . . . . . . . . . . . . .
43
43
43
44
46
48
48
48
53
54
56
56
57
58
59
60
60
61
62
62
64
66
66
Appendix A: Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendix B: Error/Warning Messages . . . . . . . . . . . . . . . . . . .
75
83
Appendix C: Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
89
Embedded Audio Input (Option 01) . . . . . . . . . . . . . . . . . . . .
89
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Contents
Operating Information . . . . . . . . . . . . . . . . . . . . . . . . . . . .
90
92
92
93
95
97
99
Changes to the Session Statistics Display . . . . . . . . . . . . .
Additional Error/Warning Messages . . . . . . . . . . . . . . . . .
Analog Line Output (Option 02) . . . . . . . . . . . . . . . . . . . . . . .
Configuring the Output . . . . . . . . . . . . . . . . . . . . . . . . . . .
Connecting the Instrument . . . . . . . . . . . . . . . . . . . . . . . .
Power Cords . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
List of Figures
Figure 1: The Tektronix 764 Digital Audio Monitor . . . . . . .
xi
2
Figure 2: Rear view of the 764 in a Tektronix enclosure . . . .
Figure 3: The 764 rear panel and connectors . . . . . . . . . . . . .
Figure 4: Connecting the standard 764 to your system . . . . . .
Figure 5: Using an external color monitor . . . . . . . . . . . . . . .
Figure 6: Outputting a session report . . . . . . . . . . . . . . . . . . .
Figure 7: The headphone output (schematic) . . . . . . . . . . . . .
Figure 8: Controls for initial power up and configuration . . .
Figure 9: The top menu HELP message . . . . . . . . . . . . . . . . .
Figure 10: Selecting from the top menu . . . . . . . . . . . . . . . . .
Figure 11: The inputs submenu . . . . . . . . . . . . . . . . . . . . . . . .
Figure 12: The 764 AUDIO/SESSION view . . . . . . . . . . . . .
Figure 13: The 764 AUDIO/PHASE view . . . . . . . . . . . . . . .
Figure 14: 764 front-panel controls . . . . . . . . . . . . . . . . . . . .
Figure 15: The 764 Level Meters . . . . . . . . . . . . . . . . . . . . . .
Figure 16: The sum and difference display modes . . . . . . . . .
Figure 17: Creating a custom meter scale . . . . . . . . . . . . . . . .
Figure 18: The Level Meters submenu . . . . . . . . . . . . . . . . . .
Figure 19: Soft buttons and numeric settings . . . . . . . . . . . . .
Figure 20: Sum and difference bars and the session display .
3
4
6
7
8
9
10
11
12
14
15
17
19
20
23
24
24
26
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Table of Contents
Figure 21: The 764 phase display . . . . . . . . . . . . . . . . . . . . . .
27
28
29
32
32
34
35
37
38
39
41
45
50
54
Figure 22: The phase correlation meter . . . . . . . . . . . . . . . . .
Figure 23: The 764 AUDIO/SESSION view . . . . . . . . . . . . .
Figure 24: The SYNC ERR Flags . . . . . . . . . . . . . . . . . . . . . .
Figure 25: Sync Error Reporting in the Absence of a DAR . .
Figure 26: A short session report . . . . . . . . . . . . . . . . . . . . . .
Figure 27: Additional data on the long report . . . . . . . . . . . . .
Figure 28: The Channel Status view, text mode . . . . . . . . . . .
Figure 29: The Channel Status view, binary mode . . . . . . . . .
Figure 30: The User Data view, text mode . . . . . . . . . . . . . . .
Figure 31: The Restore Setups submenu . . . . . . . . . . . . . . . . .
Figure 32: An “in-bar” warning message . . . . . . . . . . . . . . . .
Figure 33: The “interpolation OFF” message . . . . . . . . . . . . .
Figure 34: The De-emphasis flags . . . . . . . . . . . . . . . . . . . . .
Figure 35: Connecting to a DTE device with a DB25
serial port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
63
Figure 36: Connecting to a DCE device with a DB25
serial port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
64
91
93
97
98
Figure 37: The Audio view with digital video input selected .
Figure 38: Option 02 connectors . . . . . . . . . . . . . . . . . . . . . . .
Figure 39: Standard balanced-output pin assignments . . . . . .
Figure 40: Connecting to an unbalanced input . . . . . . . . . . . .
List of Tables
Table 1: Correlation meter speed averaging intervals . . . . . .
Table 2: Level Meters submenu . . . . . . . . . . . . . . . . . . . . . . .
Table 3: De-emphasis submenu . . . . . . . . . . . . . . . . . . . . . .
Table 4: Phase Display submenu . . . . . . . . . . . . . . . . . . . . . .
Table 5: Headphones submenu . . . . . . . . . . . . . . . . . . . . . . .
Table 6: Input submenu items (standard instrument) . . . . . .
Table 7: Option 01 input submenu, audio inputs selected . . .
47
49
53
54
56
56
57
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Contents
Table 8: Option 01 input submenu, video inputs selected . . .
57
57
58
59
60
60
61
62
67
68
70
71
75
76
76
76
77
77
78
79
79
80
89
94
95
99
Table 9: Time Code submenu . . . . . . . . . . . . . . . . . . . . . . . .
Table 10: Serial Port submenu items . . . . . . . . . . . . . . . . . . .
Table 11: Save Setups submenu . . . . . . . . . . . . . . . . . . . . . .
Table 12: Restore Setups submenu . . . . . . . . . . . . . . . . . . . .
Table 13: Screen Saver submenu . . . . . . . . . . . . . . . . . . . . .
Table 14: Service submenu . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 15: RS-232 pin assignments . . . . . . . . . . . . . . . . . . . . .
Table 16: General remote control commands . . . . . . . . . . . .
Table 17: Remote control GET commands . . . . . . . . . . . . . .
Table 18: Remote control PRESS commands . . . . . . . . . . . .
Table 19: Remote control MENU commands . . . . . . . . . . . .
Table 20: Digital audio inputs . . . . . . . . . . . . . . . . . . . . . . . .
Table 21: Level Meters and Phase Display . . . . . . . . . . . . . .
Table 22: SMPTE Time Code inputs . . . . . . . . . . . . . . . . . . .
Table 23: Interface parameter measurements . . . . . . . . . . . . .
Table 24: Headphone output . . . . . . . . . . . . . . . . . . . . . . . . .
Table 25: VGA output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 26: Physical characteristics . . . . . . . . . . . . . . . . . . . . .
Table 27: Power requirements . . . . . . . . . . . . . . . . . . . . . . . .
Table 28: Environmental characteristics . . . . . . . . . . . . . . . .
Table 29: Certifications and compliances . . . . . . . . . . . . . . .
Table 30: Option 01 characteristics . . . . . . . . . . . . . . . . . . . .
Table 31: Option 02 characteristics . . . . . . . . . . . . . . . . . . . .
Table 32: Output configuration jumper locations . . . . . . . . .
Table 33: Power cord identification . . . . . . . . . . . . . . . . . . . .
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Table of Contents
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General Safety Summary
Review the following safety precautions to avoid injury and prevent
damage to this product or any products connected to it. To avoid
potential hazards, use this product only as specified.
Only qualified personnel should perform service procedures.
To Avoid Fire or Personal Injury
Use Proper Power Cord
Use only the power cord set provided with this product, or some
other properly rated and approved cord set configured for the local
mains supply outlets.
Use Proper Power Source
This product is designed to operate from a power source that will
apply no more than 250 V
between the supply conductors, or
RMS
between either supply conductor and ground.
Ground the Product
Before connecting the product’s input or output terminals, plug the
power cord into a properly wired receptacle. A protective ground
connection, through the grounding conductor in the power cord, is
essential for safe operation.
Use Proper Fuse
Use only the fuse type and rating specified for this product.
Operate Only Within a Suitable Enclosure
Operate this product only within an enclosure that prevents contact
with interior electrical components.
Provide Proper Ventilation
Refer to the manual’s installation instructions for details on installing
the product so that it has adequate cooling ventilation.
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General Safety Summary
Use in a Proper Environment
Do not operate this product in wet/damp locations/conditions or in
explosive atmospheres.
Observe All Terminal Ratings
To avoid fire or shock hazard, observe all ratings and markings on
the product. Consult the product manual for further ratings
information before making connections to the product.
Safety Terms and Symbols
Terms in this Manual
These terms may appear in this manual:
WARNING. Warning statements identify conditions or practices that
could result in injury or loss of life.
CAUTION. Caution statements identify conditions or practices that
could result in damage to this product or other property.
Terms on the Product
These terms may appear on the product:
DANGER indicates an injury hazard immediately accessible as you
read the marking.
WARNING indicates an injury hazard not immediately accessible as
you read the marking.
CAUTION indicates a hazard to property including the product.
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General Safety Summary
Symbols on the Product
The following symbols may appear on the product:
Double
Insulated
DANGER
High Voltage
Protective Ground
(Earth) Terminal
ATTENTION
Refer to
Manual
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General Safety Summary
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Preface
The Tektronix 764 Digital Audio Monitor shown in Figure 1 is a tool
for monitoring the signal levels and stereo phase of digitally-encoded
(AES/EBU and IEC 958 “consumer use”) audio in a production
environment. The instrument can simultaneously display the levels
of two two-channel inputs, and the stereo phase relationship of any
two of the four input channels. It can also display numerical data
about the audio program material as well as “Channel Status” and
“User Data” information encoded in the digital audio signal.
Figure 1: The Tektronix 764 Digital Audio Monitor
Through on-screen menus and front-panel controls, the user may
configure the response dynamics (ballistics), reference levels, offset,
and scale of the meters to suit the monitoring needs of the particular
installation or situation. The user may also choose among several
types of stereo phase display.
This Manual
This User Manual is divided into the following sections:
H Getting Started — All the information you’ll need to put your
new instrument in service. Begins on page 13.
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Preface
H Operating Basics — What you’ll need to know for day-to-day
operation of the 764. Begins on page 13.
H Reference — Begins on page 43.
H Appendices — Instrument characteristics; Options/Accessories;
User Service. Begin on page 75.
H Glossary — Begins on page 101.
H Index — Begins on page 103.
Contacting Tektronix
Phone
1-800-833-9200*
Address
Tektronix, Inc.
Department or name (if known)
14200 SW Karl Braun Drive
P.O. Box 500
Beaverton, OR 97077
USA
Web site
www.tektronix.com
Sales
1-800-833-9200, select option 1*
support
Service
support
1-800-833-9200, select option 2*
Technical
support
Email: [email protected]
1-800-833-9200, select option 3*
1-503-627-2400
6:00 a.m. – 5:00 p.m. Pacific time
*
This phone number is toll free in North America. After office
hours, please leave a voice mail message.
Outside North America, contact a Tektronix sales office or
distributor; see the Tektronix web site for a list of offices.
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Getting Started
This section contains information you’ll need to put your 764 Digital
Audio Monitor into service. For a detailed description of instrument
capabilities, and instructions for its use, refer to the Operating Basics
section of this manual.
Unpacking
Please save the packaging material in case you must later ship the
instrument for calibration or service.
The following accessory items are included with the 764 Digital
Audio Monitor:
H This user manual
H A power cord
Any cabinet ordered with the instrument is shipped in a separate
carton.
Mechanical Installation
To accommodate the installation needs of users worldwide, Tektronix
provides the 764 without an enclosure (cabinet). To ensure proper
cooling, electromagnetic shielding, and protection against accidental
electrical shock, install the instrument in the Tektronix enclosure that
best suits your application.
NOTE. The Tektronix 764 meets EMI/EMC standards when shielded
interconnect cables are used, and when installed in one of the
following Tektronix enclosures:
H 1700F00, Plain cabinet for 1/2 rack width
H 1700F02, Portable cabinet including feet and handle
H 1700F05, Dual side-by-side rackmount adapter
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Getting Started
Order the appropriate enclosure through your nearest Tektronix field
office or representative.
WARNING. Do not carry an instrument in one of the optional
enclosures without first installing the cabinet mounting screws as
shown in Figure 2. Without the mounting screws, an instrument can
slip out of its cabinet if tipped forward. Property damage or injury
may result.
Figure 2: Rear view of the 764 in a Tektronix enclosure
Connecting the 764 to Your System
Except for the headphone jack, all connectors are on the rear panel of
the 764, shown in Figure 3. The connections you make will depend on
your particular installation and operating environment. See the
following paragraphs for explanations of the connectors and their
functions.
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Getting Started
Figure 3: The 764 rear panel and connectors
(1) Digital Audio Inputs and Loop-Throughs
The 764 has two, two-channel digital audio inputs, one labeled
CH 1–2, and the other labeled CH 3–4. Each input in the standard
instrument has two passive loop-throughs that allow you to switch the
instrument off with no effect on the through signal:
H Balanced XLR connectors for signals conforming to the AES/EBU
(AES3-1992) standard. Set the TERM switches immediately below
these connectors to EXT when the 764 is installed in-line; select
110 Ω (internal termination) when the instrument is at the end of
the signal path.
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Getting Started
NOTE. The male XLR connectors of instruments equipped with
Option 02 (Analog Line Output) are labeled ANALOG OUT; these
instruments do not have provision for loop-through on the balanced
XLR connectors.
The balanced XLR inputs of Option 02 instruments are unterminated
when the associated TERM switches are set to EXT. To avoid signal
degradation, always leave the TERM switches of Option 02 instru-
ments set to 110 Ω.
Refer to Appendix C: Options for more information about Option 02.
H 75 Ω BNC connectors that accept unbalanced, digital audio signals
in both professional (AES/EBU) and consumer (IEC958) formats.
These inputs have no provision for internal termination; if the 764
is placed at the end of a signal path, install a 75 Ω end-line
termination (Tektronix part number 011-0102-00) on the unused
loop-through connector.
An RCA phono plug-to-BNC male cable or adapter may be
required to input consumer digital audio. Plug is available in North
America through Markertek Video Supply,
telephone: 800-522-2025.
Figure 4: Connecting the standard 764 to your system
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Getting Started
NOTE. The balanced (XLR) loop-throughs are the default 764 inputs.
To receive a signal through the unbalanced (BNC) loop-throughs or
the optional serial video loop-through (Option 01), you must first
reconfigure the instrument through the on-screen menus. Refer to
Initial Power Up and Configuration on page 9 for instructions.
(2) Time Code Inputs
VITC — Reads vertical interval time code from NTSC or PAL analog
video per IEC publication 461 specifications. The time code can be
shown on the SESSION display, and stamped on each error on a
printed Session Report. The format of the Session View time display is
Hours:Minutes:Seconds.
LTC — Reads linear time code that also conforms to IEC specifica-
tions. The time code can be shown on the Session display, and
stamped on each error on a printed Session Report. The format of the
time display is Hours:Minutes:Seconds:Frames.
(3) Reference Inputs
Connect your “house” digital audio reference (DAR) signal to one of
the REF IN connectors. These connectors (one BNC, one XLR) accept
the same formats as the Digital Audio Inputs. They are internally
terminated. As with the audio inputs, the default connector is XLR;
use the on-screen menus to select the BNC connector. The 764 can use
any AES signal as a DAR; it will use the reference input to detect and
measure frame synchronization of AES signals.
If you do not connect a house DAR to one of the reference inputs, the
764 will monitor synchronization of the CH 3–4 input signal with the
CH 1–2 input signal. For more information, refer to the explanation of
the Frame Synchronization Error session statistic on page 32.
(4) VGA Video Output
To see a larger, color image of the 764 display (as illustrated in
Figure 5), connect a VGA-compatible monitor to this standard 15-pin
output. Table 25 on page 77 lists the characteristics of the Video
Output signal.
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Getting Started
VGA or SVGA
Monitor
Tektronix 764 Monitor
From VGA VIDEO Output
Figure 5: Using an external color monitor
(5) RS-232 Communications Port
Through the RS-232 port, you can:
H Output a record of the input signal and program, either to an
ASCII printer or a personal computer (see Figure 6) running a
communications application, such as PROCOMM or the Terminal
accessory of Microsoft Windows. Refer to Session Reports
beginning on page 34.
H Operate the instrument (serial number B020000 and later) by
remote control. Refer to Remote Control Commands, beginning on
page 66, for more information.
H Download future 764 software upgrades through a personal
computer. Please contact your Tektronix representative, or the
nearest Tektronix office, for information about software upgrades.
Installation instructions are provided with each upgrade kit.
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Getting Started
Via RS-232
Print or Store
Tektronix 764 Monitor
Printer
Computer
Figure 6: Outputting a session report
(6) Optional Serial Video Loop-Through
Instruments equipped with Option 01 (Embedded Audio Input) have
two additional 75 Ω BNC connectors, SER. VIDEO IN and SER.
VIDEO OUT. These connectors make up a loop-through that accepts
digital video with embedded digital audio.
Refer to Appendix C: Options, beginning on page 89, for more
information about Option 01.
Headphones
The front-panel headphone output lets you listen to the audio
programs contained in the digital input signals. The connector accepts
1
a standard ń inch (6.35 mm) stereo plug and is wired as shown in
4
Figure 7. Adjust the output level with the VOLUME knob.
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Getting Started
Figure 7: The headphone output (schematic)
By factory default, the headphone output automatically follows the
phase display; that is, it contains the audio programs decoded from the
two channels that you are monitoring with the Lissajous pattern and
correlation meter. You may also choose to listen to any two of the
input channels, independent of the phase display choices; for
instructions, refer to Selecting Headphone Channels on page 48.
Supplying Power
You can operate the 764 on any AC power supply that provides 90 to
250 V at 50 to 60 Hz. If the power cord supplied with your instrument
is incorrect for your local AC supply, please contact your nearest
Tektronix representative or field office.
WARNING. Line voltage will be present in the instrument whenever
power is supplied even if the POWER switch is set to STANDBY.
Always disconnect the power cord before removing the instrument
from its cabinet.
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Getting Started
Initial Power Up and Configuration
Once you have connected a signal source to at least one of the 764
DIGITAL AUDIO inputs, switch the instrument On. When the start-up
diagnostics are completed, the instrument will begin operation in the
Audio View/Session display.
If a signal source is connected through one of the XLR inputs, the
program level should be shown in the corresponding meters. If the
input is through a BNC connector, you must reconfigure the input with
the following procedure before you can monitor the signal. In either
case, please take this opportunity to familiarize yourself with the 764
front panel controls (Figure 8), menu structure, and techniques.
Figure 8: Controls for initial power up and configuration
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Getting Started
Perform the following steps to select the input types and familiarize
yourself with the 764 menu structure:
1. Press the MENU button to enter the TOP MENU.
2. When the 764 is in menu mode, MENU provides access to
context-sensitive HELP messages. Press MENU now to see the TOP
MENU help message; the display resembles Figure 9. Press the
button again to clear the message.
Figure 9: The top menu HELP message
3. The knob icon appears in the upper-right corner of the display
when the multi-function knob is active. Here, you may turn the
knob to scroll among the TOP MENU choices. Turn the knob now
to scroll the menu highlight to the “Inputs” entry, as shown in
Figure 10.
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Getting Started
Figure 10: Selecting from the top menu
4. The five buttons immediately to the right of the display are called
soft buttons. The printed/molded lines to the left of these buttons
serve to associate the buttons with on-screen menu choices or
functions. In Figure 10, the bottom soft button is associated with
the SUBMENU function, but you can press any soft button to enter
1
the Inputs submenu. After you do, the display resembles Figure
11.
5. To change the channel 1–2 input to the BNC connector, press the
soft button to the right of the “BNC-unbalanced” choice. The
change is in effect when you exit the menu and return to normal
operation.
1
Because there are no other soft button assignments in the top menu level,
the 764 is configured so that pressing any one of the five soft buttons will
select the highlighted submenu.
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Getting Started
Figure 11: The inputs submenu
6. Turn the multi-function knob to move the menu highlight to the
“CH 3–4 input:” line.
7. If desired, change the channel 3–4 input to the BNC connector by
pressing the associated soft button.
8. Press the CLEAR MENU button to exit the menus and resume normal
operation. If you have selected the appropriate input type, the
corresponding level meters should now respond to the input audio
program.
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Operating Basics
This section contains the basic information needed to use your 764.
The subsections are: Overview, Front Panel Controls, The Level
Meters, The Phase Display, The Session Display, Session Reports,
The Channel Status View, The User Data View, and Other Features.
Please take a few minutes to familiarize yourself with this section
and the information contained in it. Consult the text whenever you
have a question regarding instrument operation. Because the
Tektronix 764 Digital Audio Monitor is intended as a tool for use in
a production environment, every effort has been made to keep
operation as simple and intuitive as possible. An attempt has also
been made to keep this section of the manual brief and easy to use.
You will find detailed information about the more technical aspects
of 764 operation in the Reference section of this manual.
Overview
The 764 permits in-line monitoring of the audio program contained
in a digital audio signal without first converting it to analog form. In
addition, it can report and interpret the ancillary data that is
transmitted through the Channel Status and User Data bits of the
digital data stream.
The 764 uses three display views to perform those functions—the
Audio view, the Channel Status view, and the User Data view—as
described in the following paragraphs. (To locate buttons mentioned
in the text, refer to Front Panel Controls beginning on page 16.)
Monitoring an Audio Program with the Audio View
The Audio view (with the Session Statistics displayed, as shown in
Figure 12) is the power-up default configuration of the 764.
Otherwise, the Audio View is never more than two button presses
away:
1. Press the CLEAR MENU button to exit any on-screen menu.
2. Press the VIEW:AUDIO button.
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Operating Basics
The left portion of the Audio view display always contains four “bar
graph” level meters. The right portion contains either a numerical
display of session statistics (see Figure 12), or the Phase display
(shown in Figure 13). Configure the right side of the Audio view
display with the three PHASE DISPLAY buttons: A, B, and
SESSION.
Figure 12: The 764 AUDIO/SESSION view
The 764 has many options that affect the appearance and behavior of
the Audio view features. For more information, refer to The Level
Meters beginning on page 18; Sum and Difference Bars on page 25;
The Phase Display on page 26; and The Session Display on page 29.
Session Reports
The 764 can also output session reports, which are permanent records
of session activity, through the rear-panel RS-232 port. The reports
can either be sent directly to a printer, or captured on a PC and saved
to disk.
This feature adds important utility to the 764 because it permits
screening of digital audio programs for errors and peak levels
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Operating Basics
without requiring constant operator attention. When errors and peaks
are encountered, they are time-stamped with the active session time
code, which makes it easy to return to the part of the program that
contains the event of interest. See page 34 for more information.
Figure 13: The 764 AUDIO/PHASE view
Monitoring the Ancillary Data
You can monitor ancillary data contained in the digital audio signal
through two additional 764 view options.
Channel Status View. The Channel Status view reports the information
embedded in the channel status bytes of the incoming serial digital
signal. Select the Channel Status view by pressing CLEAR MENU
(if necessary, to exit the on-screen menus), then the VIEW:CH.
STATUS button. You may select a number of Channel Status view
options with the Soft buttons to the right of the display. Refer to The
Channel Status View beginning on page 37 for more information.
User Data View. The User Data view reports the information embedded
in the User bytes of the incoming signal. Select the User data view
by pressing CLEAR MENU (if necessary, to exit the on-screen
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Operating Basics
menus), then the VIEW:USER DATA button. You may select a
number of User Data view options with the Soft buttons. Refer to
The User Data View beginning on page 39 for more information.
Other Features
With the 764, you can also save up to three instrument configurations
(setups) for later recall. Refer to page 40.
Front-panel Controls
Figure 14 shows the 764 front panel controls.
(1) POWER switch. Press the POWER switch to toggle between ON
and STANDBY. A portion of the instrument power supply re-
mains active when the switch is in the Standby position. Unplug
the 764 if it is necessary to isolate it completely from the main
power supply; instrument settings are preserved with internal bat-
tery back up.
(2) VIEW Selection buttons. Use the VIEW buttons to select among the
AUDIO, CH(annel) STATUS, and USER DATA views. These
buttons are inactive when a menu is present on the 764 display.
The OTHER button is not used in this version of the instrument.
(3) PHASE DISPLAY and SESSION buttons. Use the PHASE DISPLAY
buttons to configure the right portion of the Audio view.
The A and B PHASE DISPLAY buttons select a Lissajous Phase
display with correlation meter, as illustrated in Figure 13. The A
and B phase pairings are, by default:
H Pair A, left = input channel 1; Pair A, right = input channel 2.
H Pair B, left = input channel 3; Pair B, right = input channel 4.
You can change the orientation of the Lissajous display (from
soundstage to X–Y) and the phase channel pairings through
on-screen menus. Refer to The Phase Display Submenu beginning
on page 54 for more information.
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Operating Basics
The SESSION button selects a Session Statistics panel,
illustrated in Figure 12. Refer to The Session Display beginning
on page 29 for more information.
Figure 14: 764 front-panel controls
(4) METER SCALE buttons. Use the METER SCALE buttons to change
the Audio view level meter scale. The default scale, selected with
NORMAL, is illustrated in Figure 12. Use EXPAND and OFF-
SET—with the multi-function knob—to configure the range and
offset of the custom scale. Refer to The Level Meters beginning
on page 18 for more information.
(5) Multi-function knob. Turn the multi-function knob to expand and
offset the meter scale, and to scroll various on-screen menus. The
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Operating Basics
LED immediately above the knob will light and a knob icon will
appear in the upper-right of the display when the knob is active.
(6) MENU button. Press MENU to invoke the display menu and call up
context-sensitive help text when a menu is on screen.
(7) Soft buttons. The five white soft buttons are used to select choices
or toggle settings that are indicated on the CRT display. In Fig-
ure 12, for example, the top soft button is used to toggle the Ses-
sion between Run and Stop.
(8) CLEAR MENU button. Press CLEAR MENU to exit the on-screen
menu and return to the most recent view (Audio, Channel Status,
or User Data).
(9) Headphone VOLUME control. The VOLUME knob controls the ana-
log headphone output gain; on instruments equipped with Option
02, it also controls the gain of the rear-panel analog audio out-
puts.
(10)Display BRIGHTNESS control. Turn the BRIGHTNESS knob to ad-
just the brightness of the 764 display. Does not affect the output
of the rear-panel VGA VIDEO connector.
The Level Meters
The 764 level meters are vertical bar graphs in which the height of
each bar indicates the amplitude of the audio program contained on
the corresponding input channel. The levels of all four input channels
are shown in the default meter configuration, illustrated in Figure 15.
You can also select—through on-screen menus—“two channel plus
sum and difference” mode, shown in Figure 16.
Indeed, almost every feature of the 764 level meters may be
customized to suite your particular needs. The features and your
options are explained briefly in the following numbered paragraphs.
Choose the options that are appropriate to your particular application
through the on-screen menus; refer to Configuring the Level Meters
beginning on page 22 for more information.
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Operating Basics
Figure 15: The 764 Level Meters
(1) Meter Ballistics (i.e., dynamic response, or attack/decay character-
istics of the meters). The meters can emulate the dynamic re-
sponse of three common types of analog audio level meter.
Choices are VU with the scale extended to permit display of true
peaks on the same bar; PPM, a quasi-peak meter with 10 ms in-
tegration time and slow decay; and True Peak, with instantaneous
response and slow decay.
(2) Scale Units (dBFS or dBr). By default, the zero dB mark is at digital
full scale, and units are in dB relative to full scale (dBFS). You
may also set the 0 dB mark to either the Peak Program level or
the Test level—see items (3) and (4) below. In either case, the
scale units are dB relative to the specified zero point (dBr).
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Operating Basics
Figure 16: The sum and difference display modes
(3) Peak Program level. The Peak Program level is usually the maxi-
mum permissible level for audio program material. The default
Peak Program level is –8 dBFS; you may set it to the integer val-
ue between 0 (FS) and –30 dBFS that is appropriate to your par-
ticular needs. The diamond-shaped Peak Program level scale
markers will be red on an (optional) external color display; if the
audio program exceeds this level, the portion of the meter bar
above the level will also be red.
(4) Test Level. Test level is also known as Reference level or Line-up
level. The diamond-shaped Test level marker will be yellow on
an external color display, and the part of the meter bar between
this level and Peak Program level will also be yellow. The default
test level is –18 dBFS; it may be set to any integer between 0 and
–30 dBFS.
(5) Variable scale. The scale range and offset may be adjusted through
the METER SCALE:EXPAND and :OFFSET buttons. This
feature lets you more closely monitor program levels in a selected
portion of the meter, such as immediately above and below the
Test level. To adjust either the range or offset, press the appropri-
ate button, then turn the multi-function knob. Press METER
SCALE:NORMAL to restore the default meter scale.
H The normal range is 70 dB (0 dBFS to –70 dBFS); custom
range may be as little as 10 dB or as great as 90 dB.
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H Shape: The upper 20 dB of the scale is linear in dB; the scale
is progressively compressed below –20 dBFS.
H The upper limit of the meter scale is the anchor for expansion
and compression; that is, the top scale number remains the
same when you expand or compress the scale.
H The lower limit (bottom) of the scale cannot be adjusted
below –90 dBFS; the upper limit (top) cannot be higher than
0 dBFS, or lower than –20 dBFS.
(6) Mute indicator (and other messages). The MUTE indicator is one of
seven messages that can appear in the lower half of each meter
bar. The remaining messages are intended to alert you to possible
errors in the input signal; they are explained in In-Bar Warning
Messages beginning on page 44.
You can specify the number of consecutive all-zero samples
required for a MUTE indication. The default is 10 samples; the
range is 0 to 100. The Mute indicator always reacts to unpro-
cessed input data, regardless of Interpolation or de-emphasis
settings (refer to Interpolation on page 50 or The De-emphasis
Submenu on page 53).
You may also specify the persistence (hold time) for the in-bar
indicators between 1 and 30 seconds; the default is 2 seconds.
(7) Meter bar labels. The meter bar labels depend on the display mode.
The channel numbers (1, 2, 3, and 4) correspond to the rear-panel
input labels; “Sum” indicates (L+R)/2, and “Diff” indicates
(L–R)/2.
(8) True peak indicators. The true peak indicators always show true
peak values, regardless of the selected meter ballistics. These
indicators are particularly useful when you have selected PPM or
VU ballistics, which have rise times that may prevent you from
seeing peaks in program material containing steep transients. By
default, the peak indicators persist at the most recent program
peak for 2 seconds; you can set this “peak hold time” (through
the level meters submenu) between 0 and 10, in one-second in-
crements.
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Operating Basics
Please be aware that although the peak indicators may reveal
higher peaks than VU or PPM ballistics, the indicators do act on
the same, processed data as the meters. If interpolation is ON, the
peak indicators show peaks in the oversampled data, and these
peaks may be higher than those in the raw input data (see
“Interpolation,” on page 50). If de-emphasis (AUTO, CCITT
J.17, or 50/15) is selected, the peaks—particularly at higher
frequencies—may be lower than in the raw data (refer to The
De-emphasis Submenu on page 53).
(9) Clipping flag. The clipping flag appears when the 764 detects clip-
ping and persists for the same hold time as chosen for the Mute
indicator. The user can specify the number of consecutive full
scale samples that constitute clipping. The range is from 1 to 100
samples. Like the Mute indicator, the clipping flag always reacts
to unprocessed input data, regardless of Interpolation or de-em-
phasis settings.
Configuring the Level Meters
You can configure the level meter scale with front-panel controls.
Other meter characteristics—such as ballistics, scale units, and
program/test levels—are configured through the on-screen Level
Meter submenu.
Variable scale. To adjust either the range or offset of the level meters,
press METER SCALE:EXPAND or METER SCALE:OFFSET,
then turn the multi-function knob. For best results (and least
confusion), expand the scale to the desired range first, then adjust the
offset to view the meter region of interest. For example, to change
normal scale to a custom scale showing only the –10 to –30 dBFS
range (see Figure 17):
1. Press METER SCALE:EXPAND, then turn the multi-function
knob clockwise [
] to expand the scale range to 20 dB, top to
bottom.
2. Press METER SCALE:OFFSET, and turn the multi-function
knob counterclockwise [
] to shift the scale upwards by
10 dB.
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Press METER SCALE:NORMAL to restore the default meter
scale; to later restore the “custom” scale and offset, press METER
SCALE:CUSTOM.
Figure 17: Creating a custom meter scale
Level Meter Submenu selections. All remaining level meter configura-
tion selections are made through the Level Meter submenu. Follow
the steps below to make menu selections. As with meter scale, all
selections apply to all four input channels, and all four meter bars.
1. Press CLEAR MENU, if necessary, to exit any menu and resume
normal operation.
2. Press MENU to enter the root menu (the TOP MENU).
3. Turn the multi-function knob to scroll the menu highlight to the
Level meters entry.
4. Press any soft button to enter the level meters submenu. The
display will resemble Figure 18.
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Operating Basics
Figure 18: The Level Meters submenu
5. Again, use the multi-function knob to scroll the menu highlight to
the parameter you wish to configure. The soft button assignments
will change to reflect your choice of settings. For menu items that
have numeric settings, the top two soft buttons become
increment/decrement controls designated with up and down arrow
icons, as represented in Figure 19.
Figure 19: Soft buttons and numeric settings
6. Press the soft button that corresponds to the desired setting, or
that increments or decrements the numeric value. (A numeric
value will continue to increase or decrease as long as you hold
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Operating Basics
the button down—or until you reach an adjustment limit.)
Changes are confirmed by changed text after the parameter name
in the submenu column on the left side of the screen.
7. Repeat steps (5) and (6) until you have configured the meters to
suit your needs.
8. Press the TOP MENU soft button to return to the top menu, or
press CLEAR MENU to exit the menus and resume normal
operation.
Sum and Difference Bars
When Sum and Difference bars are selected, the two left-hand bars
show the levels of one input pair (either channels 1 and 2, or
channels 3 and 4), and the right-hand bars emulate the sum and
difference bars of an analog audio monitor, such the Tektronix 760.
Note that the “sum” is actually one-half of the sum of the left- and
right-channel data, while the “difference” is one-half of the
difference between the channels. That is:
L ) R
L * R
Sum +
Diff +
2
2
The Sum and Difference bars use the same scale and ballistics, and
all other settings, as the channel level meters. Session statis-
tics—other than sum and difference peaks—are not accumulated for
the Sum and Difference bars, because they would be either
meaningless or redundant. See Figure 20 and The Session Display
beginning on page 29 for more information.
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Operating Basics
Figure 20: Sum and difference bars and the session display
The Phase Display
The 764 Phase display is a Lissajous pattern display augmented with
a (phase) Correlation meter. It is designed for convenient, qualitative
monitoring of the phase relationship between any two input channels.
The Phase display always uses interpolated (4X “oversampled”) data,
even if interpolation is turned off in the level meters submenu. You
can set the instrument for either Soundstage or X–Y orientation of
the Lissajous pattern, as illustrated in Figure 21.
NOTE. The orientation of the Lissajous pattern, phase channel
pairings, and Correlation meter speed (see below) are selected
through the Phase Display submenu. Please see page 54, in the
Reference section of this manual, for details.
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Figure 21: The 764 phase display
The Lissajous Pattern
The Lissajous portion of the phase display is a plot of one channel
against another on an orthogonal pair of axes. The X–Y orienta-
tion—shown on the right in Figure 21—plots left channel data along
the vertical axis and right channel data on the horizontal axis,
emulating the conventional X–Y display of an oscilloscope. The
default “Soundstage” orientation, shown on the left in Figure 21,
rotates the X–Y pattern 45 degrees counterclockwise so that the
channel data are plotted along diagonal axes, and mono (or in-phase)
audio appears along the vertical (“straight ahead”) axis.
If you are unfamiliar with Lissajous phase patterns and their
interpretation, see Tektronix application note 21W-6244-2, “Stereo
Audio Measurements Using the 760A Audio Monitor.” The concepts
discussed apply to the Lissajous display of the 764 as well.
The Correlation Meter
The Correlation meter, illustrated in Figure 22, displays a true
mathematical phase correlation (mono compatibility) between the
two channels of the phase pair, independent of signal amplitude. You
may find it easier to interpret the correlation meter than the Lissajous
pattern. The position of the diamond-shaped pointer indicates the
correlation between the two selected channels. The meter will read
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Operating Basics
+1 when the channels contain identical signals (frequency and
phase); it will measure –1 when the signals have the same frequency
(or frequencies), but are 180 degrees out of phase. A center-scale (0)
reading indicates uncorrelated—or random—signals.
Figure 22: The phase correlation meter
When you monitor audio programs (as opposed to simple test tones)
with the 764, the pointer will usually read between +0.5 and +1, and
will move as the correlation between the two channels changes.
Choose the time constant of the meter—and thus the speed of meter
response—through the Phase Display submenu.
AGC
AGC (automatic gain control) keeps the Lissajous pattern visible and
within the bounds of the phase display for signal levels between
0 dBFS and approximately –40 dBFS. When the AGC is Off, full
scale is equivalent to the Peak Program level (refer to page 20). AGC
does not affect the correlation meter Press the bottom soft button
(immediately above CLEAR MENU) to toggle AGC On/Off.
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The Session Display
The session display is a dynamic readout of session history; it is
illustrated in Figure 23. When the 764 is in Audio view, press the
PHASE DISPLAY:SESSION button to toggle between the Phase
display and the Session display.
Figure 23: The 764 AUDIO/SESSION view
Features of the Session Display
The following numbered paragraphs correspond to the numbered
features visible in Figure 23.
(1) Time readout in hours:minutes:seconds:frames. By default, this is
“Session time.” Session time is the time elapsed since the session
was started, or since the most recent session reset.You can set the
764—through the Time Code submenu—to display VITC (Verti-
cal Interval Time Code) or LTC (Linear Time Code) in place of
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Session time. The instrument time-stamps any errors encountered
during the Session with the chosen time code; the information is
saved in NVRAM for use when you output a Session report (refer
to page 34).
(2) Run(ning)/Stop(ped) indicator and soft button assignment. This
indicator is associated with the top soft button, immediately be-
low the MENU button. The current state is highlighted. Run
means that the Session is running, and statistics are accumulating.
Stop means that the Session has been suspended, or stopped.
Press the soft button to toggle the Session between Run(ning) and
Stop(ped).
(3) Session Statistics, explained below.
(4) RESET Session indicator and soft button assignment. This indica-
tor is visible only when the Session is stopped. Press the
associated soft button (immediately above CLEAR MENU) to
reset all Session statistics to 0 or blank (unknown). Note that a
Session reset erases all Session statistics from memory; if you
plan to output a Session report, do so before you reset the Ses-
sion.
(5) Copy soft button — is present when SHORT REPORT or LONG
REPORT has been selected through the Serial Port submenu and
the session has been stopped but not reset. Press the soft button to
output a session report to an attached printer or personal comput-
er. Refer to Session Reports beginning on page 34 for more
information.
Session Statistics
The session display reports these values for the four input channels:
H Highest true peak in the session. It is equal to the highest peak
indicator reading on the corresponding level meter, and does not
depend on the meter Scale & Ballistics selected through the
Level Meters submenu.
H Highest meter bar reading (“bar rdg”) of the session. This
corresponds to the highest reading of the meter bar, which—for a
given audio program—may depend on the meter Scale &
Ballistics selected through the Level Meters submenu.
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H Number of CLIPs detected during the session. This is directly
affected by the “Consecutive FS Samples for CLIP” setting in the
Level Meters submenu.
H Number of MUTEs detected during the session. Affected by the
“Consecutive ‘0’ Samples for Mute” setting in the Level Meters
submenu.
H Number of invalid samples encountered during the session. The
764 counts a sample as invalid when its validity bit is set high.
All these fields will read “off” when the “Ignore Validity Bit”
item in the Level Meters submenu is set to YES.
H Number of parity errors detected during the session. This will
increment if the 764 detects incorrect parity in a received digital
audio word. Parity errors suggest problems with the digital signal
source or signal path.
H Code Violations — the number of “raw” serial data subframes
containing biphase coding errors that are encountered during the
session. Code Violations indicate an incorrect or unreliable serial
digital signal or transmission path.
H The digital audio word length, detected by monitoring bit activity
in the part of the digital signal reserved for audio sample data.
Although it is not likely, this number can differ from the sample
length information indicated in the Channel Status bits of the
digital input signal.
H DC Offset — reported in dBFS (dB relative the the full scale
amplitude of the input signal). Note that an offset of –60 dBFS is
only 0.001 of the full scale amplitude, while an offset of
–5
–90 dBFS is approximately 3.16 ꢀ 10 of full scale.
H The measured sample rate. This number is independent of the
sample rate indicated in the Channel Status bits of the digital
input data, but should be the same. Non-standard sample rates
can cause constantly changing frame synchronization errors and
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SYNC ERR flags as shown in Figure 24. Please see the following
paragraphs for more information.
Figure 24: The SYNC ERR Flags
H Frame Synchronization Error — for each input with respect to the
Digital Audio Reference (DAR), when one is present at the
REFERENCE input. Otherwise—when both inputs are active but
no DAR is present—the error of input 3–4 relative to input 1–2,
as depicted in Figure 25. Errors are expressed as the percentage
of a complete digital audio frame.
Notice the “No Reference Signal” message in Figure 25. It will
appear whenever a DAR is absent from the REFERENCE input.
Figure 25: Sync Error Reporting in the Absence of a DAR
The AES11 standard specifies that synchronization errors should
be no greater than 25% of the audio sample frame. When the
synchronization error exceeds this limit, a SYNC ERR flag
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displays under the meter bars of the unsynchronized input.
Figure 24 shows the flags as they would appear if each input
signal preceded or followed the DAR signal by more than 25% of
a frame.
The SYNC ERR flags also appear when the input signal sample
frequency varies from the reference frequency by 0.01 kHz or
more. Any such frequency mismatch will cause the input signal
to “slide” relative to the reference with constantly changing sync
error; the 764 detects this and displays the appropriate SYNC
ERR flag(s) at all times—not just when the error exceeds 25%.
Both the “No Reference Signal” message and the SYNC ERR
flags may be suppressed through the Level Meters submenu; refer
to page 52 for details.
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Operating Basics
Session Reports
The 764 can output the data collected during a session—in the form
of ASCII text session Reports, through the rear-panel RS-232
connector. You can print reports on a serial printer, or save them to
files on an IBM-compatible Personal Computer (PC). The 764 can
generate two types of session report, short (Figure 26) and long
(Figure 27).
Tektronix 764 Session Screen Report
(short report)
----------------------------------------------------------------------------
Title____________________________________________________Date_______________
Time Code used: Session HH:MM:SS
Starting time 00:00:00
Ending
time 00:00:41
Elapsed time 00:00:41
----------------------------------------------------------------------------
Settings:
Display Mode:
4 Channels
Interpolation:
ON
TRUE PEAK
-8
Ballistics:
Peak Program Level (dBFS):
Test Level (dBFS):
-18
Consecutive full-scale samples for clip:
Consecutive zero samples for mute:
De-emphasis used on channel 1:
De-emphasis used on channel 2:
De-emphasis used on channel 3:
De-emphasis used on channel 4:
1
10
NONE
NONE
NONE
NONE
----------------------------------------------------------------------------
| Channel 1| Channel 2| Channel 3| Channel 4|
--------------------------+----------+----------+----------+----------+-----
Highest True Peak Reading |
-0.7
|
0
|
0
|
0
| dBFS
--------------------------+----------+----------+----------+----------+
Highest Bar Reading -0.7 | dBFS
--------------------------+----------+----------+----------+----------+
Clips Found 234 234
--------------------------+----------+----------+----------+----------+
Mutes Found 15 17
--------------------------+----------+----------+----------+----------+
Invalid Samples Found
--------------------------+----------+----------+----------+----------+
Parity Errors Found
--------------------------+----------+----------+----------+----------+
Code Violations Found 11 12 27 33
--------------------------+----------+----------+----------+----------+
Number of Active Bits 24 24 24 24
--------------------------+----------+----------+----------+----------+
DC Offset -58.9 | -70.3 | -52.2 | -62.0 | dBFS
--------------------------+----------+----------+----------+----------+
|
|
0
|
0
|
0
|
0
|
0
|
|
|
|
|
|
0
|
0
|
|
0
|
0
|
0
|
0
|
|
0
|
0
|
0
|
0
|
|
|
|
|
|
|
|
|
|
|
|
Starting Sample Rate
Ending Sample Rate
Number of changes
|
|
|
44.10
48.00
3
|
|
|
48.00
48.00
3
| kHZ
| kHZ
|
--------------------------+----------+----------+----------+----------+
Frame Sync Error | %
|
3
|
0
--------------------------+----------+----------+----------+----------+-----
Figure 26: A short session report
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The short report, shown in Figure 26, is a record of what happened
during the session. It contains a print-out of the statistics tabulated on
the 764 Session display, and lists several instrument settings that can
affect meter behavior.
In addition to all the information in the short report, the long report
contains time-stamped peak and error data and gives more detail
about active bits, DC offset, and sample rates. Figure 27 is an
example of the additional information contained in a long report.
----------------------------------------------------------------------------
Time Stamped Information Follows:
----------------------------------------------------------------------------
Highest True Peak Reading - within each 20 second interval
Channel 1
Session dBFS
00:00:09 -10.8
00:00:31 -4.9
Channel 2
Session dBFS
00:00:09 -8.1
00:00:31 0
Channel 3
Session dBFS
00:00:11 -8.1
00:00:31 0
Channel 4
Session dBFS
00:00:12 -8.1
00:00:31 0
----------------------------------------------------------------------------
Highest Bar Reading - within each 20 second interval
Channel 1
Session dBFS
00:00:10 -13.6
00:00:31 -4.9
Channel 2
Session dBFS
00:00:10 -12.1
00:00:31 0
Channel 3
Session dBFS
00:00:12 -12.1
00:00:30 0
Channel 4
Session dBFS
00:00:12 -12.1
00:00:30 0
----------------------------------------------------------------------------
Clips Found - NONE
----------------------------------------------------------------------------
Mutes Found
Channel 1
Session
Channel 2
Session
Channel 3
Session
00:00:32
Channel 4
Session
00:00:32
00:00:37
00:00:37
----------------------------------------------------------------------------
Invalid Samples Found - NONE
----------------------------------------------------------------------------
Parity Errors Found - NONE
----------------------------------------------------------------------------
Code Violations Found
Channel 1
Session
00:00:17
Channel 2
Session
00:00:17
Channel 3
Session
Channel 4
Session
00:00:36
00:00:36
----------------------------------------------------------------------------
Number of Active Bits
Channel 1
Channel 2
Channel 3
Channel 4
Minimum
Bits
0
Minimum
Bits
0
Minimum
Bits
0
Minimum
Bits
0
00:00:13
Maximum
00:00:13
Maximum
00:00:13
Maximum
00:00:13
Maximum
Bits
Bits
Bits
Bits
00:00:00 24
00:00:00 24
00:00:00 24
00:00:00 24
----------------------------------------------------------------------------
DC Offset
Channel 1
Channel 2
Channel 3
Channel 4
Minimum
dBFS
nil
Minimum
dBFS
nil
Minimum
dBFS
nil
Minimum
dBFS
nil
00:00:00
Maximum
00:00:00
Average
00:00:00
Maximum
00:00:00
Average
00:00:00
Maximum
00:00:00
Average
00:00:00
Maximum
00:00:00
Average
dBFS
nil
dBFS
nil
dBFS
nil
dBFS
nil
dBFS
nil
dBFS
nil
dBFS
nil
dBFS
nil
----------------------------------------------------------------------------
Sample Rate
Channels 1-2
Session kHZ
Channels 3-4
Session kHz
00:00:12 48.00
00:00:26 00.00
----------------------------------------------------------------------------
Figure 27: Additional data on the long report
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Operating Basics
There are two types of time-stamped information, peak readings and
error events. Peak readings are the highest true peak and the highest
meter reading encountered during each consecutive peak reading
interval in the session. An error event is a clip, mute, invalid sample,
parity error, or code violation episode, consisting of at least one such
error.
The time stamp is the hour:minute:second:frame when the peak or
error occurred, in the time format—Session, VITC, or LTC—se-
lected through the Time Code submenu.
Use the following procedure to output a session report:
1. Connect the 764 to the printer or PC. Cable requirements are
explained under Using the RS-232 Port beginning on page 62.
2. Select the appropriate communications and report options (flow
control, baud rate, type of report, and peak reading interval)
through the Serial Port submenu; for more information, refer to
Serial Port Submenu beginning on page 58. Be sure to set the
Copy selection to either SHORT REPORT or LONG REPORT.
3. Run a session.
4. Stop the session, but do not reset it. Press the Copy soft button
(feature ➄ in Figure 23 on page 29). The 764 will send the report
to the printer or PC, indicating the remaining number of lines on
the bottom of the display. Press the soft button a second time to
cancel the report.
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The Channel Status View
The 764 Channel Status view displays the channel status information
that is embedded in AES3-1992 (professional) or IEC-958 (consum-
er) digital audio signals. Press CLEAR MENU (if necessary to exit a
menu), then the VIEW:CH. STATUS button to select the Channel
Status view.
You can choose to display the Channel Status in one of four formats:
fully decoded text (the default, illustrated in Figure 28), binary
(Figure 29), transmission-order binary, or hexidecimal. To change
display formats, press the soft button assigned to the desired format,
as listed on the right side of the Channel Status View.
H In Text mode, the Channel Status data is spelled out in “plain
English,” as shown in Figure 28. The 764 will decode embedded
channel status data per AES3-1992 or IEC-958 depending on the
state of the first-transmitted channel status bit (bit 0 of byte 0).
Press the top (CHAN) soft button to toggle between the two input
channel pairs (1&2 and 3&4).
Figure 28: The Channel Status view, text mode
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H In binary display mode (illustrated in Figure 29), you may turn
the multi-function knob to highlight various bits or blocks of bits
for same-screen “plain English” decoding. For example, bits 3
through 5 of byte 0 indicate the (pre)emphasis, if any, that has
been applied to the audio program; when you move the screen
highlight to those bits, the type of emphasis will be displayed in
decoded text near the bottom of the screen. Only one channel at a
time is shown in binary mode; the selected channel is indicated
on the top line of the display. Press the CHAN soft button
repeatedly to cycle among the four input channels.
H The “Xmsn Order Binary” display reverses the bit order to
correspond to transmission order (LSB first) of the Channel
Status bits. Use the knob as in the binary display to highlight bits
or bit-blocks for decoding. Press the CHAN soft button
repeatedly to cycle among the four input channels.
H Hex format is included for compatibility with other instrumenta-
tion. All four input channels are shown on one display.
Figure 29: The Channel Status view, binary mode
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The User Data View
The 764 User Data view is intended to display optional user
information that may be embedded in the “user bits” of digital audio
signals. As this is written, the 764 can only interpret and display data
that is block-aligned with the Channel status data; the 764 cannot
interpret IEC-908 (Compact Disk) user data. Press CLEAR MENU
(if necessary to exit a menu), then the VIEW:USER DATA button to
select the User Data view.
User data may be displayed either in Hexidecimal form or as the
equivalent ASCII text. The Text mode is shown in Figure 30. Select
the desired format by pressing the appropriate soft key. The
Hexidecimal display format has room for data from all four input
channels; the Text display shows two channels at a time. In the Text
display, press the top (CHAN) soft button to toggle between the two
input channel pairs (1&2 and 3&4).
Figure 30: The User Data view, text mode
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Saving and Restoring Setups
The 764 automatically stores current front panel and menu settings in
non-volatile RAM. The instrument restarts every time in the Audio
View/Session Display, with the session stopped and session time (if it
is the current Time Code selection) reset to zero. All other settings
will be as when the 764 was switched off.
For added flexibility, you can also save up to three instrument
configurations, recall them later, or restore the factory default
settings with the techniques described next.
Saving a Setup
You can save up to three additional instrument configurations in
NVRAM for convenient later recall through the “Save Setups”
submenu. To do so:
1. Configure the instrument as desired with the front-panel controls
and through the various submenus.
2. Enter the top menu. (Press CLEAR MENU, then MENU to enter
the top menu anytime the 764 is operating.)
3. Use the multi-function knob to scroll the menu highlight to “Save
Setups.” Press any soft button to enter the submenu.
4. Press one of the three available soft buttons to save the
instrument settings. A highlighted message—“SETUP #N has
been saved”—will appear on screen when the operation is
complete.
5. Press CLEAR MENU to resume normal instrument operation.
Restoring a Setup
To recall a setup or restore factory default settings:
1. Enter the top menu.
2. Use the multi-function knob to scroll the menu highlight to
“Restore Setups.” Press any soft button to enter the submenu. It
will resemble the display illustrated in Figure 31.
3. Press one of the four soft buttons to recall/restore the associated
instrument settings. A highlighted message—“SETUP #N has
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been restored”—will appear on screen to signal that the
operation is complete.
4. Press CLEAR MENU to resume normal instrument operation
with the newly-recalled settings.
Figure 31: The Restore Setups submenu
Editing a Setup
To edit an existing, saved setup:
1. Recall the Setup through the Recall Setups submenu.
2. Change the instrument settings as desired.
3. Save the Setup as the same setup number through the Save Setups
submenu.
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Reference
This section contains detailed information about the more technical
aspects of 764 operation. The subsections are: Level Meters,
Correlation Meter Algorithm, Selecting Headphone Channels,
Submenus, and Using the RS-232 Port.
Level Meters
Also refer to The Level Meters Submenu beginning on page 48.
Meter Ballistics and Alignment Levels
The many level meter options in the 764 may leave the user
wondering which settings to use for a given installation or applica-
tion. The short answer is to choose settings to emulate the meters
that you are accustomed to. However, you may not find the
translation between the analog and digital worlds completely
straightforward. Or, you may wish to modify your practice and adopt
certain standards to ease inter-platform and international program
exchange. In either case, the next few paragraphs may help you
decide on the Ballistics, Peak Program Level, Test Level, and “0 dB
Mark” settings for your 764.
To ease signal exchange between equipment, EBU Recommendation
R68–1992 suggests that the alignment level be set at 18 dB below
maximum digital coding level (that is, –18 dBFS). This level
corresponds to the CCIR 645 [renamed ITU–R BS.645–2] analog
alignment level, and allows adequate headroom above the permitted
maximum level for (PPM) metering and meter-reading errors. The
permitted maximum level, as defined in CCIR 645, is 9 dB (or 8 dB,
in some organizations) above the alignment level.
A practical way of configuring the 764 to implement the above
recommendation with PPM ballistics is to set the Test Level to the
EBU-recommended alignment level of–18dBFS, and set the Peak
Program Level to the permitted maximum level of –9 dBFS (or
–10 dBFS). You may choose to set the 0 dB mark to either the Peak
Program Level or Digital Full Scale. With the 764, the true peaks are
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Reference
always indicated by the peak segment, so actual headroom is always
visible.
With VU ballistics, the Test Level should correspond to the same
level as above (–18 dBFS) if program exchange is important. In
accordance with standard practice, the Test Level (“line–up level”)
corresponds to 0 VU, so you may set the 0 dB mark to the Test
Level. If program material is then peaked at 0 dB, you can expect
actual peaks to be 8 to 14 dB higher (which can be easily seen with
the true peak indicators of the 764). A good setting for the Peak
Program Level would be in the range of –8 to –10 dBFS. IEEE
152–1991 recommends that the VU meter readings of program
material be 8 dB below those of a PPM meter to get the same actual
program level. The above setup accomplishes that.
All of the above is for standardizing digital recordings or digital
transmissions for international program exchange. Individual
organizations may have their own internal standards. Some
experienced recording engineers prefer a higher alignment level than
–18dBFS to make fuller use of the available coding range for a better
S/N ratio. Others are more conservative. For example, SMPTE (in
RP 155–90) recommends a “reference” level of –20 dBFS.
And, of course, digital purists may always select True Peak ballistics.
In-Bar Warning Messages
The in-bar warning messages (for example, INPUT UNLOCKED, in
the Channel 3 and 4 meter bars in Figure 32) are listed below in
order of error condition priority. Higher priority errors preempt lower
priority ones. Messages—or “Flags”— are displayed for as long as
the error condition lasts plus n seconds, where n is the CLIP/MUTE
hold time set through the Level Meters submenu (see page 52). The
INPUT UNLOCKED and LOW CONFidence flags will always
appear in both bars of the affected input; all other messages can
appear in one or both bars, depending on channel content.
INPUT UNLOCKED —The 764 is not locked to an incoming signal on
the indicated input channel. Data cannot be decoded; all data and all
other errors are ignored. This message will appear when no input
signal is present.
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CODE ERR — A bi-phase coding violation (ERRor) has occurred in
the digital data stream. All affected data samples are unreliable, and
are therefore ignored. The instrument treats affected samples as “zero
samples” for use by the meter bars and phase display. When Session
is running, the instrument counts code violations and displays the
total on the Session view.
Figure 32: An “in-bar” warning message
PARITY — The incoming subframe does not have even parity as
specified by the applicable digital audio standards. The data sample
is unreliable and is ignored. The meter bars and phase pattern treat
the sample as a zero sample. When Session is running, the
instrument counts parity errors and displays the total on the Session
view.
LOW CONF — (Low Confidence.) This warning message indicates a
marginal signal on the serial digital interface. Problems that can
trigger this message—such as significant jitter or low signal
amplitude—will usually result in a poor “eye” pattern when the
serial digital signal is displayed on appropriate equipment.
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V BIT — Indicates that the Validity bit is set high for one or more data
samples. In the AES/EBU standard, a set validity bit indicates that
the sample is not suitable for conversion to audio. By default, The
meter bars and phase display treat the affected samples as a zero
samples. When Session is running, the instrument counts “invalid
samples” and displays the total on the Session view.
You can suppress the V BIT message by setting the “Ignore Validity
Bit” item in the Level Meters submenu to YES. If you do so, the 764
will treat all samples as valid, and the word “off” will appear in the
Invalid samples fields of the Session view. This feature is included
because the use of the Validity bit varies despite its official meaning
as specified in the AES/EBU standard, and you may find it desirable
to monitor audio from “invalid” samples.
Correlation Meter Algorithm
The correlation meter reading is calculated 60 times each second
1
from
@
-second-long blocks of interpolated (“4x oversampled”)
60
input data. The formula used to drive the correlation meter is:
2
4fsń60
ȱ
ȧ
Ȳ
ȳ
ȴ
ȍ (
)
LnRn
ȧ
n+0
C + (sign)
4fsń60
4fsń60
Ǹ
ȱ ȳȱ
ȳ
ȴ
2
2
ȍ ( ) ȍ ( )
Ln
Rn
ȧ ȧȧ
ȧ
n+0
n+0
Ȳ ȴȲ
Where
f = the sampling frequency, in Hz (for example, 48000);
s
L = the value of the nth left-channel sample; and
n
R = the value of the nth right-channel sample
n
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Reference
and
or
4fsń60
ȍ(
n +0
(
)
)
(sign) + ) 1 if
LnRn is u 0
4fsń60
ȍ(
( )
(sign) + –1 if
)
LnRn is t 0
n +0
The actual correlation meter reading is the “rolling average” of the
last i sample blocks:
C1 ) C2 ),..., ) Ci
M +
i
where i is determined by the Correlation Meter Speed setting in the
Phase Display submenu. Table 1 lists i —and the corresponding
averaging interval—for each meter speed selection.
Table 1: Correlation meter speed averaging intervals
Speed
setting
Equivalent
interval (s)
Speed
setting
Equivalent
interval (s)
i
i
1
2
1
0.0167
0.0333
0.0667
0.1333
0.2667
0.5333
1.0
11
12
13
14
15
16
17
18
19
20
180
210
240
270
300
330
360
390
420
450
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
2
3
4
4
8
5
16
32
60
90
120
150
6
7
8
1.5
9
2.0
10
2.5
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Selecting Headphone Channels
By factory default, the headphone output follows the phase display.
That is, you can listen to the audio programs that are currently
driving the Lissajous pattern and Correlation meter (refer to The
Phase Display beginning on page 26). When you change the phase
display channels—either by selecting the other display pair (A or B),
or through the phase display menu—the headphone output will
contain the audio on the newly-selected input channels.
You can also configure the headphone output to listen to any two
input channels you wish, independent of the phase display selections.
Follow these steps to make “manual” headphone selections:
1. Enter the top menu (either by pressing MENU or the TOP MENU
soft button, if already in a submenu).
2. With the multi-function knob, move the menu item highlight to
Headphones. Then press a soft button to enter the submenu.
3. Set the Audio Source to MANUAL.
4. Select the appropriate “Manual Left Channel” and “Manual Right
Channel.”
5. Press CLEAR MENU to exit the on-screen menus and resume
normal operation.
Submenus
The various 764 submenus are summarized below. See the Getting
Started section of this manual, starting on page 1, for an explanation
of general menu techniques.
The Level Meters Submenu
Use this Submenu to configure the appearance and behavior of the
Audio View level meters.
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Table 2: Level Meters submenu
Item
Choices
Factory setting
Display Mode
4 Channels
Ch 1–2 and Sum & Diff
Ch 3–4 and Sum & Diff
4 Channels
Interpolation
Ballistics
OFF; ON
ON
PPM
True Peak
Extended VU
True Peak
Peak Hold Time
0 to 10 seconds
2
Peak Program Level
(dBFS)
0 to –30 dBFS
(cannot be set below
Test level)
–8 dBFS
Test Level (dBFS)
Set 0 dB Mark to
0 to –30 dBFS
(cannot be set above
Peak Program level)
–18 dBFS
DIGITAL FULL SCALE
PEAK PROGRAM
TEST LEVEL
DIGITAL FULL SCALE
Consecutive FS Sam-
ples for CLIP
1 to 100
0 to 100
1 to 30
1
Consecutive “0” Sam-
ples for MUTE
10
2
CLIP/MUTE Hold Time
(sec)
Ignore Validity Bit
NO; YES
NO; YES
NO
NO
Suppress Sync Loss
Flags
Display Mode. Use the Display Mode setting to configure the audio
view to contain four level meters (as shown in Figures 15 and 17 on
pages 19 and 23 respectively) or two level meters plus Sum and
Difference bars. When Sum and Difference bars are selected, the two
left-hand bars show the levels of one input pair (either channels 1–2
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or channels 3–4); the right-hand bars show (L+R)/2 (Sum) and
(L–R)/2 (Diff) data derived from the two left-hand bars. The Sum
and Difference bars use the same scale and ballistics, and all other
settings, as the channel level meters.
Interpolation. When interpolation is OFF, the 764 level meters
measure the digital input data only. When interpolation is ON, the
instrument also measures interpolated data generated by a 4X
oversampling filter. Select OFF to see the levels encountered by the
digital equipment (such as recorders, processors, and transmitters) in
your system. Choose ON to see a more accurate representation of the
levels in the reconstructed analog audio program.
A display message—immediately below the level meters—reminds
you when Interpolation is set to OFF; see Figure 33.
Figure 33: The “interpolation OFF” message
Ballistics. Use the Ballistics item to configure the dynamic response
of the level meters to conform to one of three “standards”:
H PPM (peak program meter), which shows “quasi-peak” levels as
defined in IEEE Std. 152–1991 and IEC 268–10a. When PPM
ballistics are selected, the meters also contain true peak
indicators, and the display designation is “PPM + Peak.”
H True Peak, which shows actual signal peaks regardless of their
duration. Rise and Fall times are essentially instantaneous,
although the in-bar peak indicator will persist at program peaks
for the “peak hold time,” described below.
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H Extended VU, a VU meter as defined in IEEE 152–1991, but
with an extended dB-linear scale. The 764 meter bars will also
contain true peak indicators when Extended VU is selected, and
the display designation of this setting is “vu + Peak.”
Note that this setting only affects meter performance when the input
is “live,” changing audio. A constant 1000 Hz, –10 dBFS tone, for
example, will drive the meters to a constant –10 dBFS reading
regardless of which Ballistics setting is selected.
Peak Hold Time. Peak Hold time is the number of seconds that the true
peak indicator (see Figure 15, item 8 on page 19) remains at the most
recent peak. Set the hold time to 0 to turn the peak indicator Off.
Peak Program Level (dBFS). Peak Program level is the level—relative
to digital full scale—that you choose as the maximum desired level
for monitored programs. The meter bars change to maximum
brightness (on the 764 display) or red (on an external VGA monitor)
above Peak Program level.
Test Level (dBFS). Test level is the level—relative to digital full
scale—that you choose as the test or “line up” level for your system.
The meter bars change to medium brightness (on the 764 display) or
yellow (on an external VGA monitor) between the Test and Peak
Program levels.
Set 0 dB Mark to. Use this item to number the meter scale relative to
Digital Full scale or to one of the two user-adjustable levels. When
the zero mark is set to either Peak Program or Test level, the scale
units are dBr, relative to the 0 dB level; units above the selected 0 dB
mark are positive, while units below it are negative.
Consecutive FS Samples for CLIP. Select the number of successive
full-scale samples that constitute a “Clip.” This setting determines
when a clip flag (see Figure 15, item 9 on page 19) appears above a
level meter, and it also affects the number of clips detected during a
Session and included in a session report (refer to The Session Display
beginning on page 29). The range for this setting is 1 to 100; the
factory default is 1.
Consecutive “0” Samples for MUTE. Use this item to select the number
of successive full-scale samples that constitute a “Mute.” This setting
determines when a MUTE indicator (see Figure 15, item 6 on
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page 19) appears in a level meter, and it also affects the number of
clips detected during a Session and included in a session report (refer
to The Session Display beginning on page 29). The range for this
setting is 0 to 100; a setting of 0 turns mute detection Off, in which
case no mutes will be reported on the session display or in a session
report. The factory default is 10.
CLIP/MUTE Hold Time (sec). CLIP/MUTE hold time is the number of
seconds that the Clip indicator and various In-bar warning messages
will persist after the end of the Clip, Mute, or error condition. For
more information, refer to In-Bar Warning Messages beginning on
page 44.
Ignore Validity Bit. Ignore Validity Bit determines how the instrument
will react to a high (value 1) validity bit in the input data. In
AES3-1992 digital audio, a high validity bit indicates that the sample
word is not suitable for conversion to audio. When this item is set to
the factory default of “No,” the 764 will ignore any sample
accompanied by a high validity bit, display a “V BIT” flag in the
level meter, and report invalid samples on the session display and
report. When set to Yes, invalid sample reporting will be turned Off,
and the instrument will treat all samples as valid.
Suppress Sync Loss Flags. Use this setting to suppress the SYNC ERR
flags and “No Reference Signal” message when no DAR (digital
audio reference) is connected to the REFERENCE input, or to
prevent “nuisance flashing” of the SYNC ERR message when the
input signals have differing sample rates.
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The De-emphasis Submenu
The De-emphasis submenu, shown in Table 3, lets you select the
appropriate de-emphasis for each of the four input channels. Enter
the De-emphasis submenu from the TOP menu level by scrolling the
highlight to the De-emphasis item and pressing a soft button. Then
scroll the highlight to the desired channel. The four submenu items
are identical, except for the affected channel.
Table 3: De-emphasis submenu
Item
Choices
Factory setting
Channel #
NONE
NONE
(Where # = 1, 2, 3, or 4) AUTO
CCITT J.17
50/15
Selecting either CCITT J.17 or 50/15 will force that type of
de-emphasis. When AUTO is selected, the 764 will apply the
appropriate de-emphasis if either CCITT J.17 or 50/15 emphasis is
indicated in the channel status data of the digital input signal.
If you choose de-emphasis, please be aware that—although the 764
will continue to use raw input data when reporting MUTEs and
CLIPs— the level meters and session statistics will measure and
report levels in the de-emphasized signal. Because de-emphasis
attenuates the higher frequencies of a signal, selecting de-emphasis
may result in meter readings and true peak statistics that understate
the actual signal levels.
When any type of de-emphasis has been selected, it is indicated by a
“flag” on the display above the meter pair, as shown in Figure 34. In
the configuration pictured, de-emphasis has been selected for input
channels 1, 2, and 3—but not for channel 4. (If de-emphasis was
also not selected for channel 3, the “De-emp” flag would not appear
above the right-hand meter pair.)
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Figure 34: The De-emphasis flags
The Phase Display Submenu
Use the Phase Displaly submenu (Table 4) to configure the appear-
ance and behavior of the Audio View Phase display.
Table 4: Phase Display submenu
Item
Choices
Factory setting
Format
LISSAJOUS-SOUND-
STAGE
LISSAJOUS-SOUND-
STAGE
LISSAJOUS-X–Y
Correlation Meter Speed 1 to 20
8
1
Pair A Left channel as-
signment
1; 2; 3; 4
1; 2; 3; 4
1; 2; 3; 4
1; 2; 3; 4
Pair A Right channel
assignment
2
3
4
Pair B Left channel as-
signment
Pair B Right channel
assignment
Format. To change the phase display format, scroll to this menu
choice and then press the soft button that corresponds to the desired
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display orientation. Refer to page 26 for details on the phase display
formats.
Correlation Meter Speed. The Correlation Meter Speed setting
determines how quickly the meter reacts to changes in phase
relationship. The meter reading is actually an average of correlation
over time, and this setting determines how many samples are used to
calculate the average. The 764 uses the fewest samples when this
setting is 1, and the meter reacts almost instantaneously. The
instrument uses the most samples when the setting is 20, and the
meter reacts much more slowly. Experiment to find the setting that
best fits your application. For more information about this setting,
refer to Correlation Meter Algorithm on page 46.
Pair A [B] Left [Right] channel assignment. These four choices let you
pair any two of the four input channels on the phase display. By
default, channels 1 and 2 are phase pair A, and channels 3 and 4 are
pair B. You can, however, designate channels 1 and 3 or 1 and 4—or
channels 2 and 3 or 2 and 4—as either pair A or pair B.
Change the channels of the phase pairs using the following steps:
1. Press the MENU button.
2. Turn the multifunction knob until PHASE DISPLAY is
highlighted.
3. Push any of the inner group white soft key buttons to the right of
the display screen to bring up the Phase Display screen.
4. Rotate the multifunction knob to highlight Pair A left or right, or
Pair B left or right..
5. Push the appropriate white soft key buttons to set any channel 1
through 4 to left and right of either Pair A or Pair B.
6. Push CLEAR MENU button to return to the screen that was
displayed before you pushed the MENU button.
Note that if you pair channels from different inputs, the two data
streams must be synchronized. If data slippage is 1/2 frame or
greater, the 764 will not be able to unambiguously identify left-right
sample pairs and the phase display will not be reliable. If that
happens, a warning message appears on the display.
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Headphones Submenu
Use the Headphonse submenu (Table 5) to determine the input
channels to be decoded and output through the headphone jack.
Table 5: Headphones submenu
Item
Choices
Factory setting
Audio Source
AUTO (follows phase);
MANUAL
AUTO (follows phase)
Manual Left Channel
Manual Right Channel
1; 2; 3; 4
1; 2; 3; 4
1
2
Input Submenu
Select the active connectors for the digital audio and reference inputs
through this submenu.
Table 6: Input submenu items (standard instrument)
Item
Choices
Factory setting
CH 1–2 input
XLR-balanced
BNC-unbalanced
XLR-balanced
CH 3–4 input
XLR-balanced
BNC-unbalanced
XLR-balanced
XLR-balanced
Reference input
XLR-balanced
BNC-unbalanced
In instruments equipped with Option 01 (embedded audio input), the
Input submenu is changed to accommodate the additional input
choice; the submenu also changes depending on the chosen input.
Table 7 describes the input submenu in Option 01 instruments when
the audio source selection is digital audio inputs. Table 8 describes
the submenu when digital video input is selected.
Please refer to Appendix C: Options, beginning on page 89, for more
information about Option 01.
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Table 7: Option 01 input submenu, audio inputs selected
Item
Choices
Factory setting
Audio Source
Digital Audio Inputs
Digital Video Input
Digital Audio Inputs
XLR-balanced
XLR-balanced
XLR-balanced
CH 1–2 input
CH 3–4 input
Reference input
XLR-balanced
BNC-unbalanced
XLR-balanced
BNC-unbalanced
XLR-balanced
BNC-unbalanced
Table 8: Option 01 input submenu, video inputs selected
Item
Choices
Factory setting
Audio Source
Digital Audio Inputs
Digital Video Input
(see Table 7)
Channels
1 through 4
5 through 8
9 through 12
13 through 16
1 through 4
Time Code Submenu
Select the time code to be displayed on the Session Display and used
to time-stamp errors on Session reports.
Table 9: Time Code submenu
Item
Choices
Factory setting
Time code in use
SESSION
VITC
SESSION
LTC
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Serial Port Submenu
The Serial Port submenu contains items used for setting the serial
port parameters and controlling the content of the session report. The
items and choices are listed in Table 10 and explained in the
subsequent paragraphs.
Table 10: Serial Port submenu items
Item
Choices
Factory setting
Flow Control
SOFTWARE; HARD-
WARE; BOTH; NONE
SOFTWARE
Baud Rate
Copy
38400; 19200; 9600;
2400
38400
NO REPORT; SHORT
REPORT; LONG RE-
PORT
NO REPORT
Peak Reading Interval
(sec)
0, 1, 2, ..., 300 (seconds) 60
Flow Control. Scroll to the “Flow Control:” menu choice (by turning
the multi-function know) and then press the soft button that
corresponds to the appropriate type of flow control. If you do not
know which flow control is correct for your application, first try
HARDWARE when outputting a report to a printer, and SOFTWARE
when downloading a report to a personal computer.
Baud Rate. Scroll to the “Baud Rate:” menu choice and press the soft
button that corresponds to rate that is used by the receiving printer or
PC. For fastest data transfer when outputting a session report to a PC,
select the highest baud rate available in both the 764 and the PC;
then, if you experience difficulty with flow control between the 764
and the PC, set both to the next lower baud rate available and try
again.
Copy. The Copy submenu item determines the type of report that is
output when you press the Copy soft button (see Figure 23). When
NO REPORT is selected, the “Copy” function is removed from the
third soft button, and you cannot output a Session Report.
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Peak Reading Interval (sec). Use this item to choose the duration of the
peak reading intervals. When a session is running, the 764 stores the
time and value of the highest true peak and meter bar readings
encountered during each interval. The time-stamped peaks are
included in a long report; see Figure 27 (on page 35).
H This setting does not apply to error events (clips, mutes, Invalid
samples, Parity Errors, and Code Violations).
H Program peaks are not stored when the setting is 0 (zero).
H Peaks are time-stamped with the time (Session, VITC, or LTC)
that has been selected through the Time Code submenu.
The length of time you may accumulate session statistics depends on
this setting and the number of error events that occur. Assuming few
clips, mutes, or other errors, the 764 has enough memory for at least
30 minutes of records when the interval is set to 1 second, and over
30 hours when the factory setting (60 seconds) is used. Choose an
interval that is appropriate to your situation; be aware that the 764
can store enough peak data to fill over 70 pages of text.
NOTE. To prevent unexpected results, change this setting immediately
after a session reset only, and not during a session.
Save Setups Submenu
Save the current instrument configuration through the Save Setups
submenu (Table 11). The current settings will overwrite any
configuration previously saved in the Setup.
Table 11: Save Setups submenu
Item
Choices
Factory setting
Selection
SETUP #1
SETUP #2
SETUP #3
(not applicable)
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Restore Setups Submenu
Restore a previously saved instrument configuration through the
Restore Setups submenu (Table 12). The current instrument settings
will be replaced by those in the saved Setup.
Table 12: Restore Setups submenu
Item
Choices
Factory setting
Selection
SETUP #1
SETUP #2
(not applicable)
SETUP #3
FACTORY SETUP
Screen Saver Submenu
Select a suitable delay in the Screen Saver submenu (Table 13) to
help prevent display “burn in.” Choose an interval long enough to
prevent activation during program monitoring. When the screen
saver is active, press any button to restore the normal display.
Table 13: Screen Saver submenu
Item
Choices
Factory setting
Delay in Hours
OFF, 1, 2, ..., 23 (hours) OFF
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Service Submenu
Use the Service submenu (Table 14) to select patterns for use in
adjusting the display; find the version of software installed in the
instrument and the instrument’s firmware identification number; and
superimpose a numeric readout of signal levels on the Session
display. Refer to the 764 service manual for more information.
Table 14: Service submenu
Item
Choices
Factory setting
Adjustment
MONITOR CROSS-
HATCH
(not applicable)
Information
SOFTWARE VERSION (not applicable)
IDENTIFICATION NUM.
Numeric Level Readout OFF; ON
OFF
Adjustment. Once you choose this item, you can cycle through the
four available test patterns by repeatedly pressing the top soft button.
Patterns are used in adjusting the display during manufacture.
Information. Press the appropriate soft button to access the corre-
sponding information.
Numeric Level Readout. This readout is intended for use in manufac-
ture only; it obscures a large part of the Session display.
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Using the RS-232 Port
The primary use of the 764 RS-232 port is to output session reports.
The reports can be sent directly to any ASCII printer with serial
input, or captured on a PC and saved to disk.
The RS-232 port also supports remote control of 764 Digital Audio
Monitors with serial number B020000 and higher. To control the
instrument from a personal computer or ASCII terminal, connect it
as discussed under Cable Requirements and confirm the connection
by downloading a session report to the computer or terminal. Then
refer to the Remote Control Commands section, which begins on
page 66.
Cable Requirements
The 764 is an RS-232 DCE device. Table 15 lists the pin assignments
of the connector. When communicating with a DTE device that has a
male 9-pin (DB9) connector, use a cable that connects pins 2, 3, 5, 7,
and 8 straight-through (example: Tektronix part number
012-1445-00). To communicate with another DCE device, use a null
modem cable (which swaps the lines between pins 2 and 3 and pins 7
and 8). Figure 35 and Figure 36 illustrate cable wiring for communi-
cating with a device that has a 25-pin serial connector.
Table 15: RS-232 pin assignments
764 DB9 pin
Signal name
Signal direction
1
2
3
4
5
6
7
8
9
(optional)
—
From 764
To 764
—
RXD (Received Data)
TXD (Transmitted Data)
(optional)
Signal Ground
(optional)
—
—
RTS (Request to Send)
CTS (Clear to Send)
(optional)
To 764
From 764
—
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NOTE. RS-232 signals are named from the perspective of the DTE
device. Since the 764 is a DCE device, pin 2 (Received Data) is an
output from the instrument; that is, the data is received by the
connected DTE device.
The 764 supports both hardware (RTS/CTS) and software (Xon/Xoff)
handshaking; choose the appropriate handshaking protocol through
the Serial Port submenu. Set the serial communication parameters of
the connected device to 8 bits, 1 stop bit, and no parity. Be sure that
the same Baud rate is selected at the 764 and the connected device.
Figure 35: Connecting to a DTE device with a DB25 serial port
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Figure 36: Connecting to a DCE device with a DB25 serial port
NOTE. Most Personal Computers are DTE devices; however, printers
may be either DTE or DCE, and the type may not be obvious from
the printer documentation or the gender of the RS-232 connector. If
you have trouble outputting a 764 Session report, first verify that
communication parameter and Baud rate settings are correct, then
try reversing the conductors at pins 2 and 3 and 7and 8 at the cable
end that is connected to the 764.
Communication Examples
The following hardware/software and 764 settings have been verified
effective for either printing a session report to a printer or download-
ing the report to a PC running Microsoft Windows 3.1. You may find
the examples helpful; please note, however, that mention of
third-party software or equipment does not constitute endorsement or
recommendation by Tektronix, Inc. The settings required for your
particular printer, PC, and communications software may vary.
Printing. You can use the hardware and software settings described
below to print a session report.
H Printer/port: QMS-PS 410/serial (DB25)
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H Printer Communications Settings:
ESP (automatic protocol sensing)
9600 (baud)
8 (bits)
1 (stop bit)
DTR/DSR (flow control)
H 764 Serial Port settings:
Flow Control = HARDWARE
Baud Rate = 9600
Communicating with a PC. You can use the software and settings below
to establish communications with a personal computer.
H PC Software: Microsoft Windows 95 Hyperterminal Accessory
application. Many other communications or terminal applications
also work.
H Hyperterminal application File menu, Properties command,
Connect To tab settings:
Connect Using = COMX (depends on computer configuration;
often COM2 when a serial mouse is installed)
Configure...
Baud Rate = 19200 (or 38400)
Bits = 8
Stop Bits = 1
Parity = none
Flow Control = Xon/Xoff
H 764 Serial Port settings:
Flow Control = SOFTWARE
Baud Rate = 19200 (or 38400)
Be sure to set compatible baud rates before attempting to establish
communications. At power-on of the 764, a command prompt (764>)
and product identification message will be displayed on the PC or
terminal screen when connected.
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Outputting a Session Report
You can test your RS-232 connection by outputting a short session
report.
1. Confirm that the Copy selection of the 764 Serial Port submenu is
set to either SHORT REPORT or LONG REPORT.
2. Clear the on-screen menu and display the Audio Session view.
3. Run a session.
4. Stop the session, but do not reset it.
5. Press the on-screen Copy soft button (feature ➄ in Figure 23 on
page 29). The 764 will send the report to the printer or PC. As it
sends the report, the monitor indicates the number of remaining
lines on the bottom of the display. Press the soft button a second
time to cancel the report.
Remote Control Commands
Once you have established communications between the 764 and a
personal computer or ASCII terminal, you may use the remote
control commands to operate the audio monitor from the computer or
terminal.
Command Syntax. Use the colon (:) as the command argument
separator as in the following examples:
PRESS:SKEY4 (the command to press soft key number 4)
MENU:DISMODE:1 (the command to display the sum and
difference of Channel 1 and Channel 2)
You can string the remote commands together on a single command
line. Use a semicolon (;) to separate commands on the line as in the
following example:
PRESS:APH;GET:CURTP:2;GET:SHIGH:2;…
The commands are not case-sensitive although this section shows
them in all uppercase for clarity. You can also abbreviate the
commands. Only enough letters to make the command unique need
be used in a command as shown in the following example:
G:T;G:SA:1;P:AU
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The example command gets the time, gets the sample rate from the
Channel 3 – Channel 4 input, and presses the View Audio button.
When you abbreviate a command, you cannot leave out letters in the
middle of a command argument. If the complete argument is needed
to make a command unique, all the argument alphanumerics must all
be used. For example:
PRESS:SKEY5can be abbreviated as p:skey5, but the complete
argument is necessary. The unique letter or number is the last one
of the argument.
If you send an abbreviated argument that is not unique, the first
command in the list that is recognized is done. If you send a
command with unrecognized syntax, an error message is displayed
showing the incorrect command. If you are in doubt about an
abbreviation, use the entire argument.
General Commands. Table 16 lists and explains the general or
miscellaneous 764 remote control commands.
Table 16: General remote control commands
Command
HELP
Effect
Displays the list of remote commands
KNOB:UP:<1–10>
Scrolls up a menu or data list by the specified
number of positions or turns the knob one incre-
ment “up.”
KNOB:DOWN:<1–10>
Scrolls down a menu or data list by the specified
number of positions or turns the knob one incre-
ment “down.”
KNOB:?
Displays the syntax for the KNOB command
Turns command echo on; echo on is the default.
ECHO:ON
ECHO:OFF
Turns command echo off; your command entry will
not appear on the computer or terminal display.
ECHO
Displays the current state of ECHO, on or off.
ECHO:?
Displays the syntax of the ECHO:ON/OFF
command
RESET
Resets the instrument to a power-up state.
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Table 16: General remote control commands (Cont.)
Command
Effect
MSGON:<text>
Displays a temporary message up to 58 charac-
ters on the top line of the 764 display. Excess text
does not wrap; it is truncated.
MSGOFF
Removes the temporary message.
Returns the last command error.
SYSTEM:ERROR
SYSTEM:ERROR:CLEAR Clears the last command error.
GET Commands. GET commands retrieve information from the 764;
Table 17 lists and explains the GET commands.
SYNTAX:
GET:mnemonic:<number> (no number or
invalid number returns all selections for the mnemonic).
Table 17: Remote control GET commands
Command
GET:?
Value = selection Retrieves
none
none
Lists all the GET commands
GET:mnemonic
All the values for the command
mnemonic
GET:TIME
none
Current (Session, LTC, or
VITC) time
GET:FRAME:<0–1>
GET:SAMPR:<0–1>
GET:RAWSR:<0–1>
0=Ch 1–2 input
1=Ch 3–4 input
Frame Sync Errors
0=Ch 1–2 input
1=Ch 3–4 input
Sample rate
0=Ch 1–2 input
1=Ch 3–4 input
Raw sample rate
Error flags
GET:ERRFLAG:<0–1> 0=Ch 1–2 input
1=Ch 3–4 input
GET:BARFLAG:<0–3> 0=Meter bar #1
1=Meter bar #2
Bar flags
2=Meter bar #3
3=Meter bar #4
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Reference
Table 17: Remote control GET commands (Cont.)
Command Value = selection Retrieves
GET:WARFLAG:<0–3> 0=Meter bar #1
1=Meter bar #2
Warning flags
2=Meter bar #3
3=Meter bar #4
GET:CURTP:<0–3>
GET:SPEAK:<0–3>
GET:RAWTP:<0–3>
GET:CURHP:<0–3>
GET:SHIGH:<0–3>
GET:RAWHP:<0–3>
0=Meter bar #1
1=Meter bar #2
2=Meter bar #3
3=Meter bar #4
Current true peak
Session true peak
Raw true peak
0=Meter bar #1
1=Meter bar #2
2=Meter bar #3
3=Meter bar #4
0=Meter bar #1
1=Meter bar #2
2=Meter bar #3
3=Meter bar #4
0=Meter bar #1
1=Meter bar #2
2=Meter bar #3
3=Meter bar #4
Current high peak
Session high peak
Raw high peak
0=Meter bar #1
1=Meter bar #2
2=Meter bar #3
3=Meter bar #4
0=Meter bar #1
1=Meter bar #2
2=Meter bar #3
3=Meter bar #4
GET:FILESPACE
GET:LREPORT
GET:SREPORT
none
none
none
File space free
Long session report
Short session report
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Reference
PRESS Commands. Each front-panel button (except the power switch)
has an equivalent PRESS:<button> command. Send the command to
perform the same action as pressing the button.
Table 18: Remote control PRESS commands
Command
Equivalent button
Lists all the PRESS commands
PHASE DISPLAY:A
VIEW:AUDIO
PRESS:?
PRESS:APH
PRESS:AUDIO
PRESS:BPH
PHASE DISPLAY:B
VIEW:CH STATUS
CLEAR MENU
PRESS:CHSTAT
PRESS:CLEAR
PRESS:CUSTOM
PRESS:EXPAND
PRESS:NORMAL
PRESS:MENU
PRESS:OFFSET
PRESS:OTHER
PRESS:SESSION
PRESS:SKEY1
PRESS:SKEY2
PRESS:SKEY3
PRESS:SKEY4
PRESS:SKEY5
PRESS:USER
METER SCALE:CUSTOM
METER SCALE:EXPAND
METER SCALE:NORMAL
MENU
METER SCALE:OFFSET
VIEW:OTHER
PHASE DISPLAY: SESSION
Soft Button #1 (top)
Soft Button #2
Soft Button #3
Soft Button #4
Soft Button #5 (bottom)
VIEW:USER DATA
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Reference
MENU Commands. Use the MENU commands listed in Table 19 to
make selections from the 764 on-screen menus. The menus need not
be visible on the display to change a setting with a MENU command.
SYNTAX: MENU:mnemonic:<number> (unrecognized
number returns "Out Of Range Error")
Table 19: Remote control MENU commands
Command
Value = setting
Submenu, item
MENU:?
Lists the Menu commands
MENU:mnemonic:?
Lists the command syntax for the
queried mnemonic and gives the
current setting
MENU:DISMODE:<0–2>
0=4 Channels
1=Ch 1–2 + Sum & Diff
2=Ch 3–4 + Sum & Diff
Level Meters, Display Mode
MENU:INTERP:<0–1>
0=ON
1=OFF
Level Meters, Interpolation
Level Meters, Ballistics
MENU:BALLIST:<0–2>
0=True Peak
1=PPM
2=Extended VU
MENU:PHTIME:<0–10>
0 to 10 seconds
Level Meters, Peak Hold Time
MENU:PPGMLVL:<–30–0> –30 to 0 dBFS
Level Meters,
Peak Program Level
MENU:TESTLVL:<–30–0> –30 to 0 dBFS
Level Meters, Test Level
MENU:ZERODB:<0–2>
0=Dgt. Full Scale (dBFS) Level Meters, Set 0 dB Mark to
1=Peak Program (dBr)
2=Test Level (dBr)
MENU:CLIP:<1–100>
MENU:MUTE:<0–100>
MENU:CMTIME:<1–30>
MENU:IGVBIT:<0–1>
1 to 100 samples
0 to 100 samples
1 to 30 seconds
Level Meters, Consecutive FS
Samples for CLIP
Level Meters, Consecutive “0”
Samples for MUTE
Level Meters,
CLIP/MUTE Hold Time(sec)
0=NO
1=YES
Level Meters, Ignore Validity Bit
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Table 19: Remote control MENU commands (Cont.)
Command
Value = setting
Submenu, item
MENU:SYNCF:<0–1>
0=NO
1=YES
Level Meters,
Suppress Sync Loss Flags
MENU:DEEMP1:<0–3>
MENU:DEEMP2:<0–3>
MENU:DEEMP3:<0–3>
MENU:DEEMP4:<0–3>
0=None
1=Auto
2=CCITT J.17
3=50/15
De-emphasis, Channel 1
De-emphasis, Channel 2
De-emphasis, Channel 3
De-emphasis, Channel 4
0=None
1=Auto
2=CCITT J.17
3=50/15
0=None
1=Auto
2=CCITT J.17
3=50/15
0=None
1=Auto
2=CCITT J.17
3=50/15
MENU:PDISP:<0–1>
MENU:CORR:<1–20>
MENU:PALEFT:<0–3>
0=Lissajous–Soundstage Phase Display, Format
1=Lissajous–XY
1 to 20 (see page 46)
Phase Display,
Correlation Meter Speed
0=channel #1
1=channel #2
2=channel #3
3=channel #4
Phase Display,
Pair A: Left Channel Assignment
MENU:PARIGHT:<0–3>
0=channel #1
1=channel #2
2=channel #3
3=channel #4
Phase Display, Pair A: Right
Channel Assignment
MENU:PBLEFT:<0–3>
0=channel #1
1=channel #2
2=channel #3
3=channel #4
Phase Display,
Pair B: Left Channel Assignment
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Reference
Table 19: Remote control MENU commands (Cont.)
Command
Value = setting
Submenu, item
MENU:PBRIGHT:<0–3>
0=channel #1
1=channel #2
2=channel #3
3=channel #4
Phase Display, Pair B: Right
Channel Assignment
MENU:AUDSRC:<0–1>
0=Manual
1=Auto (follows phase)
Headphones, Audio Source
(also applies to Option 02)
MENU:MLEFT:<0–3>
0=channel #1
1=channel #2
2=channel #3
3=channel #4
Headphones,
Manual Left Channel
(also applies to Option 02)
MENU:MRIGHT:<0–3>
0=channel #1
1=channel #2
2=channel #3
3=channel #4
Headphones,
Manual Right Channel
(also applies to Option 02)
MENU:SOURCE:<0–1>
(Option 01 only)
0=Digital Audio Inputs
1=Digital Video Input
Input, Audio source
Input, CH 1–2 Input
Input, CH 3–4 Input
Input, Reference Input
Input, Channels
MENU:CH1–2IN:<0–1>
MENU:CH3–4IN:<0–1>
MENU:REFINP:<0–1>
0=XLR–balanced
1=BNC–unbalanced
0=XLR–balanced
1=BNC–unbalanced
0=XLR–balanced
1=BNC–unbalanced
MENU:SD_GROUP:<0–3> 0=1 through 4
(Option 01 only)
1=5 through 8
2=9 through 12
3=13 through 16
MENU:TIME:<0–2>
MENU:FLOW:<0–3>
0=SESSION
1=VITC
2=LTC
Time Code, in use
0=Software
1=Hardware
2=Both
Serial Port, Flow Control
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Reference
Table 19: Remote control MENU commands (Cont.)
Command
Value = setting
Submenu, item
MENU:BAUD:<0–3>
0=38400
1=19200
2=9600
3=2400
Serial Port, Baud Rate
(Changing the Baud rate
interrupts the remote connection)
MENU:COPY:<0–2>
0=No Report
1=Short Report
2=Long Report
Serial Port, Copy
MENU:PR–INT:<0–300>
0 to 300 seconds
Serial Port,
Peak Reading Interval
MENU:SAVE:<0–2>
0=Setup #1
1=Setup #2
2=Setup #3
Save Setups, Last Saved
(saves the current setup as
setup #n)
MENU:RESTORE:<0–3>
0=Setup #1
1=Setup #2
Save Setups, Last Restored
(restores setup #n)
2=Setup #3
3=Factory Setup
MENU:SCRSVR:<0–23>
Screen Saver, Delay in Hours
Service, Information
MENU:INFO:<0–1>
0=Software Version
1=Identification Num.
MENU:NUMERIC:<0–1>
0=OFF
1=ON
Service, Numeric Level Readout
MENU:HOME
Selects (highlights) the first item
of the current menu or submenu
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Appendix A: Specifications
Table 20: Digital audio inputs
Characteristic
Performance require-
ments
Supplemental information
Impedance
Balanced inputs (XLR)
Term switched in
Term switched out
110 Ω 5%
Return loss >30dB
0.1 MHz to 6 MHz
0.1 MHz to 6 MHz. Relative to
110 Ω load at loop-through
connector.
Unbalanced inputs
Return loss > 30dB
Relative to 75Ω load at
loop-through connector.
Input level
Balanced inputs
Unbalanced inputs
Reference input
Balanced input
Connector type
0.2 to 10 V
p–p
50 mV to 2 V
p–p
p–p
XLR, terminated, no loop-
through
Input impedance
Input level
110 Ω 10%
0.1 to 6 MHz
0.6 to 10 V
p–p
Unbalanced input
Connector type
BNC, terminated, no loop-
through
Input impedance
Input level
75Ω 10%
0.2 V to 2 V
0.1 to 6 MHz
p–p
p–p
Sample rate locking range, 27 kHz to 52 kHz
all audio inputs
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Appendix A: Specifications
Table 21: Level Meters and Phase Display
Characteristic
Performance require-
ments
Supplemental information
Attack and Decay
Characteristics:
Ballistics only: normal scale
does not comply with standards.
True Peak
PPM
PPM decay characteristics No attack delay
per IEC 268-10A and
IEEE std. 152-1991
VU
per IEEE std. 152-1991
Level Meter accuracy
0.05 dB
Steady 1 kHz tone, Full Scale to
–20 dBFS, no de-emphasis.
AGC Control Range
0 dBFS to –40 dBFS
Lissajous pattern
Table 22: SMPTE Time Code inputs
Characteristic
Information
VITC (Vertical Interval
Time Code)
Reads NTSC and PAL VITC conforming to IEC publication
461; indicates time as Hours:Minutes:Seconds.
Input connector
Input signal
BNC, 75Ω termination, no loop-through
Video with VITC, 1 volt nominal
LTC (Longitudinal Time
Code)
LTC conforming to IEC publication 461; indicates time as
Hours:Minutes:Seconds.
Input connector
Input signal
XLR balanced, 600Ω termination, no loop-through
Range: 250 mV to 10 V .
p-p
p-p
Table 23: Interface parameter measurements
Characteristic
Performance require-
ments
Supplemental information
Sample rate
Range
27 kHz to 52 kHz
0.01 kHz
Resolution
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Appendix A: Specifications
Table 23: Interface parameter measurements (Cont.)
Characteristic
Performance require-
ments
Supplemental information
Accuracy
Within .01 kHz
Synchronization
Range
40% of dig. audio frame
2% of digital audio frame
Accuracy
Indication
“Frame Sync Err” (session view)
Table 24: Headphone output
Characteristic
Performance require-
ments
Supplemental information
Output voltage
Frequency response
Balance
into 150 Ω load, 0 dBFS input
u10 V
p-p
20 Hz to 20 kHz 2 dB
0.5 dB
Distortion
20 kHz measurement bandwidth
THD+N t0.05%
Table 25: VGA output
Characteristic
Resolution
Information
640 X 480 VGA
Signal Level Voltage
White
Black
0.7 V
0 V
Blanking
Horizontal Sync
Vertical Sync
0 V
TTL, low true
TTL, low true
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Appendix A: Specifications
Table 25: VGA output (Cont.)
Characteristic
Information
Load Impedance
Red
Green
75 ohms
75 ohms
Blue
Horizontal Sync
Vertical Sync
75 ohms
TTL compatible
TTL compatible
Timing/Frequency
Dot Clock
Horizontal Rate
Vertical Rate
25.175 MHz
31.469 kHz
59.940 Hz
Pin Assignments
pin:
1
2
Red
Green
3
4
Blue
NC
5
6
7
8
Ground
Red Ground
Green Ground
Blue Ground
NC
9
10
11
12
13
14
15
Ground
NC
NC
Horizontal Sync
Vertical Sync
NC
Table 26: Physical characteristics
Characteristic
Height
Information
1
5 / inches (13.3 cm)
4
1
Width
8 / inches (21.6 cm)
2
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Appendix A: Specifications
Table 26: Physical characteristics (Cont.)
Characteristic
Information
Depth
17 inches (43.2 cm)
Weight
Net
10 lbs (4.54 kg)
17 lbs 5 oz (7.85 kg)
Shipping
Table 27: Power requirements
Characteristic
Input voltage
Information
90–250 VAC
Input frequency
Current rating
50 or 60 Hz
1.5 A Maximum
56 Watts typical
Power consumption
Table 28: Environmental characteristics
Characteristic
Information
Temperature
Operating
Storage
[NOTE: Safety certification compliance to +40 °C]
0 °C to +50 °C (32 to 122 °F)
–55 °C to +75 °C (–67 to +167 °F)
Humidity
Will operate at 93% relative humidity for up to five days
Meets requirements of the five-day humidity cycling test
described in Tektronix standard 062-2847-00
Altitude
[NOTE: Safety certification compliance to 2000 m]
to 15,000 feet (4572 m)
to 50,000 feet (15420 m)
Operating
Storage
Vibration (Operating)
15 minutes each axis at 0.013 inch, frequency varied from 7 to
55 to 7 Hz in five-minute cycles with the instrument attached
to a vibration platform
Dwell for 10 minutes each axis at any resonant frequency, or
33 Hz if no resonant frequency is found (Tektronix std.
062-2858-00).
1
Shock (non-operating)c
30 Gs, / sine, 11 ms duration; 3 shocks per surface
2
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Appendix A: Specifications
Table 28: Environmental characteristics (Cont.)
Characteristic
Information
Transportation
Meets the requirements of NTSB Test Procedure 1A, category
II (24 inch drop)
Equipment Type
Equipment Class
Measurement
Class I (grounded product)
(As defined in IEC 1010-1, Annex H.)
Installation Category
Pollution Degree
Emissions
Installation Category II
(as defined in IEC 1010-1, Annex J)
Pollution Degree 2
(as defined in IEC 1010-1; indoor use only)
47 CFR, Part 15, Subpart B,Class A
Table 29: Certifications and compliances
EC Declaration of
Conformity – EMC
Meets intent of Directive 89/336/EEC for Electromagnetic
Compatibility. Compliance was demonstrated to the following
specifications as listed in the Official Journal of the European
Communities:
EN 50081-1 Emissions:
EN 55022Class B Radiated and Conducted Emissions
EN 50082-1 Immunity:
IEC 801-2Electrostatic Discharge Immunity
IEC 801-3RF Electromagnetic Field Immunity
IEC 801-4Electrical Fast Transient/Burst Immunity
EMC Compliance
FCC Compliance
Meets the intent of Directive 89/336/EEC for Electromagnetic
Compatibility when it is used with the product(s) stated in the
specifications table. Refer to the EMC specification published for
the stated products. May not meet the intent of the Directive if used
with other products.
Emissions comply with FCC Code of Federal Regulations 47, Part
15, Subpart B, Class A Limits
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Appendix A: Specifications
Table 29: Certifications and compliances (Cont.)
Australia/New Complies with EMC provision of Radiocommunications Act per
Zealand Declaration the following standard(s):
of Conformity –
EMC
AN/NZS 2064.1/2
Industrial, Scientific, and
Medical Equipment: 1992
EC Declaration of
Conformity – Low
Voltage
Compliance was demonstrated to the following specification as
listed in the Official Journal of the European Communities:
Low Voltage Directive 73/23/EEC, Amended by 93/68/EEC:
EN 61010-1:1993
Safety requirements for electrical equipment for
measurement, control, and laboratory use
Approvals
UL3111-1 – Standard for electrical measuring and test equipment
CAN/CSA C22.2 No. 1010.1 – Safety requirements for electrical
equipment for measurement, control and laboratory use
Installation Category Terminals on this product may have different installation category
Descriptions
designations. The installation categories are:
CAT III Distribution-level mains (usually permanently
connected). Equipment at this level is typically in a fixed
industrial location
CAT II
Local-level mains (wall sockets). Equipment at this level
includes appliances, portable tools, and similar products.
Equipment is usually cord-connected
CAT I
Secondary (signal level) or battery operated circuits of
electronic equipment
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Appendix A: Specifications
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Appendix B: Error/Warning Messages
This appendix lists and explains the various error and warning
messages that can appear on the 764 display. Figure 32 on page 45
shows the In-bar message location.
Channels not synchronized
Location: Audio View, phase display.
The left and right samples are not synchronized well enough to be
reliably paired. Only possible when left and right channels are
chosen from different inputs (for example, channel 1 paired with
channel 4).
CLIP
Location: Audio View, above the meter bar of the affected channel.
The CLIP indicator flashes when the digital audio data on the input
channel remains at full scale for n or more consecutive samples. The
factory default value of n is one (1); it may be changed through the
Level Meters submenu. “Full scale” means maximum coding level,
either positive or negative. Maximum coding level is determined by
the number of active bits detected in the digital input signal.
This indicator persists for the “CLIP/MUTE Hold Time,” also set
through the Level Meters submenu. When a Session is running, the
instrument counts CLIPs and displays the current total on the
Session display.
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Appendix B: Error/Warning Messages
CODE ERR
Location: In-bar.
(Code error.) A bi-phase coding violation has occurred in the digital
data stream. All affected data samples are unreliable, and are
therefore ignored. The instrument treats affected samples as “zero
samples” for use by the meter bars and phase display.
The CODE ERRor indicator persists for the “CLIP/MUTE Hold
Time,” set through the Level Meters submenu. During a Session, the
instrument counts code violations and displays the current total on
the Session display.
CRC Error
Location: Channel Status View (lower-left corner).
The Cyclic Redundancy Code calculated by the 764 does not agree
with that calculated by the originating equipment and transmitted in
Channel Status byte 23 of the digital input signal. This discrepancy
usually results from errors in digital signal transmission.
De-emp
Location: Audio View, above meter bar of affected channel.
De-emphasis is in effect on the indicated channel. Will appear above
the affected meter bar when CCITT J.17 or 50/15 ms de-emphasis is
selected through the De-emphasis submenu, or when AUTO is
selected and pre-emphasis is indicated in the channel status bits of
the input signal.
This message persists as long as the instrument is applying
de-emphasis to the input channel.
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Appendix B: Error/Warning Messages
INPUT UNLOCKED
Location: In-bar.
The 764 is not locked to an incoming signal on the indicated input
channel. Data cannot be decoded; all data and all other errors are
ignored. Likely causes of this message include: missing input signal;
incorrect setting(s) in the Inputs submenu; or inadequate or
defective input signal(s).
The INPUT UNLOCKED indicator persists for the “CLIP/MUTE
Hold Time,” set through the Level Meters submenu.
Interpolation OFF
Location: Audio View, below meter bars (may be obscured by other
error messages).
Interpolation has been turned OFF through the Level Meters
submenu. This message will persist until Interpolation is returned to
the factory default setting of ON.
LOW CONF
Location: In-bar.
(Low Confidence.) This warning message Indicates a marginal
signal on the serial digital interface. Problems that can trigger this
message—such as significant jitter or low signal amplitude—will
usually result in a poor “eye” pattern when the serial digital signal is
displayed on appropriate equipment.
The LOW CONFidence indicator persists for the “CLIP/MUTE
Hold Time,” set through the Level Meters submenu.
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Appendix B: Error/Warning Messages
MUTE
Location: In-bar.
The MUTE indicator flashes when the digital audio data on the
input channel remains at zero-value for n or more consecutive
samples. The factory default value of n is ten (10); it may be
changed through the Level Meters submenu. A setting of zero (0)
disables this indicator.
The MUTE indicator persists for the “CLIP/MUTE Hold Time,” set
through the Level Meters submenu. When a Session is running, the
instrument counts MUTEs and displays the current total on the
Session display.
No Reference Signal
Location: Audio View, below the Session or Phase display.
The 764 is not locked to an incoming signal on the REFERENCE
input. Likely causes of this message include: missing reference
signal; incorrect “Reference Input” setting in the Inputs submenu; or
an inadequate or defective DAR signal.
The flag will persist until a valid reference signal is detected, or
until “Suppress Sync Loss Flags” is selected through the Level
Meters submenu.
No Video Input (Option 01 only)
Location: Audio View, below the Session or Phase display.
Video input is selected, but there is no video signal present at the
input. The in-bar INPUT UNLOCKED flag also appears in all four
level meter bars whenever this message is displayed.
The flag persists until a valid digital video signal is detected at the
SER. VIDEO IN connector, or until another input is selected.
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Appendix B: Error/Warning Messages
NOT PRESENT (Option 01 only)
Location: In-bar.
The NOT PRESENT flag indicates that, although video input is
detected, there is no active audio on the corresponding channel (no
channel ID is detected).
PARITY
Location: In-bar.
The incoming subframe does not have even parity as specified by
the applicable digital audio standards. The data sample is unreliable
and is ignored. The meter bars and phase pattern treat the sample as
a zero sample.
The PARITY indicator persists for the “CLIP/MUTE Hold Time,”
set through the Level Meters submenu. When a Session is running,
the instrument counts parity errors and displays the current total on
the Session display.
SYNC ERR
Location: Audio View, below the affected meter pair (1–2 or 3–4).
Either the input is out of synchronization with the REFERENCE
input signal by at least 25% of the digital audio sample frame, or the
input-to-reference timing is constantly changing due to mismatched
sampling frequencies.
When the 764 is not locked to an incoming signal on the REF-
ERENCE input, the presence of this flag below the channel 3–4
meter bars indicates that the two inputs (CH 1–2 and CH 3–4) are
out of sync with each other. Again, the signals can be mistimed by a
quarter-frame or more, or be “sliding” relative to one another due to
a sample frequency mismatch.
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Appendix B: Error/Warning Messages
To determine the exact cause of a SYNC ERR flag, select the 764
Session display and check the Sample Rate and Frame Sync Err
fields in the SESSION STATISTICS panel. See The Session Display
on page 29 for more information. The flag will persist until
synchronization is achieved, or until “Suppress Sync Loss Flags” is
set in the Level Meters submenu.
V BIT
Location: In-bar.
Indicates that the Validity bit is set high for one or more data
samples. In the AES/EBU standard, a set validity bit indicates that
the sample is not suitable for conversion to audio. By default, The
meter bars and phase display treat the affected samples as a zero
samples. When Session is running, the instrument counts “invalid
samples” and displays the current total on the Session display.
You can suppress the V BIT message by setting the “Ignore Validity
Bit” item in the Level Meters submenu to YES. If you do so, the
764 will treat all samples as valid, and the word “off” will appear in
the Invalid samples fields of the Session display. (This feature is
included because the use of the Validity bit varies despite its official
meaning as specified in the AES/EBU standard, and you may find it
desirable to monitor audio from “invalid” samples.)
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Appendix C: Options
This section describes the following options available with the 764
Digital Audio Monitor:
H Option 01, Embedded Audio Input
H Option 02, Analog Line Output (see page 93)
H Power cord options (see page 99)
Embedded Audio Input (Option 01)
Option 01 provides the ability to monitor AES/EBU digital audio
that is embedded in serial digital video.
The option, available both factory-installed and as a field-upgrade
kit, may be installed in any instrument with serial number B020000
and above. It consists of an active digital video loop-through and the
circuitry required to extract digital audio from (625- and 525-line)
Component and NTSC Composite serial digital video.
Option 01 instruments retain all features of the standard 764 Digital
Audio Monitor. Table 30 lists and describes important Option 01
characteristics.
Table 30: Option 01 characteristics
Characteristic
Description
Input video formats
270 Mbit/s component (625- and 525-line) complying
with SMPTE 259M and CCIR 656-1
143 Mbit/s NTSC composite complying with
SMPTE 259M
Audio format
Input level
SMPTE 272M level B:
20-bit; 48 kHz sampling rate; synchronized with video
800 mV "10%
p-p
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Appendix C: Options
Table 30: Option 01 characteristics (Cont.)
Characteristic
Description
Equalization range
Proper operation with up to 19.0 dB loss at 135 MHz
using coaxial cable having 1/f loss characteristics
1/2
with a launch amplitude of 800 mV
Return loss
(input and output)
w15 dB relative to 75 ohms, 1–270 MHz, power on
Output level
800 mV "10%
p-p
Operating Information
The following paragraphs explain how to monitor embedded audio
with a 764 Digital Audio Monitor equipped with Option 01. Most
procedures are the same as those used for monitoring digital audio
with a standard instrument; this section emphasizes the few
differences from standard operation as discussed in the rest of this
manual.
Connect the Instrument. Connect the 764 to the digital video signal
path with appropriate 75 W coaxial cable, such as Belden 8281.
Notice that the SER. VIDEO IN and SER. VIDEO OUT connectors
make up an active loop-through, in which the output is an equalized
and regenerated copy of the input. A termination is not required on
the serial video output when the instrument is installed at the end of
the signal path.
Select the Digital Video Input and Audio Channel Group. Configure the
764 to monitor the serial video input with the following steps:
1. Switch instrument power on.
2. Press the MENU button to enter the on-screen menu hierarchy.
3. Turn the multi-function knob to highlight the Input menu
selection; then press the SUBMENU soft button (or any white
button) to enter the Input submenu.
4. Press the soft button that corresponds to the Digital Video Input
choice. Notice that the Input submenu changes to include only
Audio Source and Channels selections.
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Appendix C: Options
5. Turn the multi-function knob to highlight the Channels menu
item; then press the soft button that corresponds to the channel
group (channels 1–4; 5–8; 9–12; or 13–16) that you want to
monitor. If you do not know which audio channels are active on
the input video, ignore the channel setting and proceed to the
next step.
6. Press the CLEAR MENU button to exit the menu hierarchy; then
press VIEW:AUDIO, if necessary, to select the audio Phase or
Session display. Notice that sixteen diamonds, arranged in four
groups of four, now occupy the top of the display as shown in
Figure 37. The diamonds represent the four groups of four audio
channels defined in SMPTE 272M. Bright diamonds indicate
active channels; a white underline indicates the channel group
that you have selected through the Input submenu. The numbers
of the selected channels appear under the meter bars.
Figure 37: The Audio view with digital video input selected
7. If there is no audio on one or more of the channels in the selected
group, the message NOT PRESENT now occupies the meter bars
of the inactive channels. If necessary, repeat steps 2, 3, and 5
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Appendix C: Options
above to select a group with active audio channels; then press
CLEAR MENU to return to the audio view.
Configure the Meters. Once you have selected the correct channel
group, you can configure the level meter scale and offset by
following the instructions under Configuring the Level Meters on
page 22. You can also select appropriate meter response characteris-
tics (ballistics) and alignment levels; refer to Level Meters, on
page 43, for more information.
Configure the Phase Display. The phase display can show the phase
relationship of any two channels in the selected channel group. By
default, phase pair A is the first two channels in the group and phase
pair B is the last two channels. For example, when the second
channel group (channels 5 through 8) is selected, phase pair A is
channel 5 left and channel 6 right, and phase pair B is channel 7 left
and channel 8 right. You can specify any pairing of the four channels
through the Phase Display submenu.
Refer to The Phase Display Submenu beginning on page 54 for
information about specifying phase pairings, setting the phase
display orientation, and setting the correlation meter speed.
Changes to the Session Statistics Display
Because Parity errors, code violations, and frame sync errors have no
meaning in embedded audio, the corresponding fields of the Session
display always contain “n/a” to signify that the parameters are not
applicable.
Additional Error/Warning Messages
There are two on-screen error/warning messages unique to
Option 01. For more information about other error and warning
messages, refer to Appendix B: Error/Warning Messages.
No Video Input. A “No Video Input” message is displayed at the
bottom of the Audio view if Video Input is selected but there is no
video signal present. The in-bar INPUT UNLOCKED flag also
appears in all four meter bars whenever the No Video Input message
is displayed.
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Appendix C: Options
NOT PRESENT. The in-bar NOT PRESENT flag indicates that,
although video input is detected, there is no active audio on the
corresponding channel (no channel ID is detected).
Analog Line Output (Option 02)
Option 02 replaces the balanced XLR digital audio outputs with
analog audio line outputs; it is available only as a factory option to
the 764 and cannot be installed in existing instruments. Option 02
has the following features and characteristics:
H The option provides two channels (typically, left and right) of
balanced analog output.
H The audio channels present on the left and right analog line
outputs are those selected by the user for headphone monitoring.
Figure 38: Option 02 connectors
H The analog output can be configured one of three ways: fixed at
+24 dBm into a balanced 600 ohm load; variable up to +24 dBm,
also for a balanced 600 ohm load; or variable up to 2.0 V
into
RMS
an unbalanced, 10 kW (or greater) load. When the instrument is
set for variable output, the front-panel VOLUME knob controls
output gain.
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Appendix C: Options
Option 02 instruments are set during manufacture for fixed
output; refer to Configuring the Output on page 95 for
information about changing the setting.
When outputting to an unbalanced load (0 to 2.0 V
variable
RMS
output only), you must connect one of the lines to ground; refer to
Connecting the Instrument on page 97 for more information.
H The analog outputs supercede the digital XLR loop-throughs;
always leave the TERM switches of Option 02 instruments set to
110 W for proper XLR input termination.
Table 31 lists and describes important Option 02 characteristics.
Table 31: Option 02 characteristics
Characteristic
Output Level
Fixed gain
Description
With 0 dBFS 1 kHz sine wave applied to the input
+24 dBm +1.6/–0.0 dBm into 600 W balanced
Variable gain,
high output
+24 dBm (volume control fully clockwise) into
600 W balanced
Variable gain,
low output
2.0 V
≥10 kW
(volume control fully clockwise) into
RMS
Output impedance, typical
Frequency Response
Distortion, THD+N
50 W
2 dB, 20 Hz to 20 kHz
<0.05% (22 kHz THD+N bandwidth)
Distortion, typical, THD+N, <0.005% at 1 kHz (control fully clockwise, load
variable gain, high output
≥10 kW, 22 kHz THD+N bandwidth)
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Appendix C: Options
Configuring the Output
Qualified service personnel can change the output configuration with
the following procedure:
CAUTION. The 764 contains static-sensitive components. The
following procedure should be performed by qualified technicians
only.
1. Disconnect power and all other connections from the 764 rear
panel and then remove the instrument from its enclosure. The
Analog Line Output circuit board assembly is mounted
horizontally above the audio XLR connectors at the rear of the
chassis. The configuration jumper pins are readily accessible on
the top surface of the board.
2. Identify the jumper configuration in Table 32 that corresponds to
the desired output; add and remove jumpers to/from the jumper
pin pairs to achieve that configuration. Pin pairs J20, J21, J22,
and J23 are provided as a convenient place to “park” unused
jumpers. If you need additional jumpers for the new configura-
tion, take them from J20–J23; if you have extra jumpers after
reconfiguration, put them onto J20–J23.
Table 32: Output configuration jumper locations
Output
Jumper configuration
AES connector*
Fixed, +24 dBm
J914
Variable, to +24 dBm
J913
J913
Variable, to 2.0V
RMS
* See configuration procedure step 3.
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Appendix C: Options
3. Locate J913 and J914, the two rows of six connector pins on the
AES circuit board assembly. The AES board is on the right side
of the 764 when you view the instrument from the rear panel;
J913 and J914 are near the end of the AES board that is closest to
the front of the instrument. The AES–XLR cable must be
connected to either J913 or J914; use J914 for fixed analog audio
output and use J913 for variable output.
If you move the AES–XLR cable, be sure to connect pin one of
the cable connector to pin one on J913 or J914. Pin one is
indicated by a triangular symbol on the circuit board and a
triangular symbol and white dot on the cable connector.
4. Reinstall the 764 in its enclosure and reconnect it to your system.
The appropriate analog audio cable connections depend on the
analog output configuration. Refer to Connecting the Instrument
on page 97 for analog audio cable requirements.
5. The audio input channels routed through the left and right analog
line outputs are the same as on the front-panel headphone output.
During manufacture, the headphone output is set to follow the
phase display. You may manually select the headphone and
analog line output channels through the Headphones submenu;
refer to Selecting Headphone Channels on page 48 for more
information.
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Appendix C: Options
Connecting the Instrument
The appropriate method of connecting the Option 02 analog outputs
to your system depends on the configured output level and the
requirements of your particular installation.
High-level, Balanced Output. When using high-level fixed or variable
balanced output, connect the 764 to your system with standard
shielded XLR cables. The analog line output polarity matches Figure
39 when the instrument is configured for variable high-level output.
If you are using fixed output, and output phase must match input
phase, reverse the connections to pins 2 and 3.
Male XLR
Pin 1 (shield)
Pin 2 (+)
Pin 3 (–)
Figure 39: Standard balanced-output pin assignments
Low-level, Unbalanced Output. When using low-level output to drive an
unbalanced load such as a consumer amplifier, you must use cables
that short either pin 2 or pin 3 to pin 1, the shield/ground. The output
will not meet the distortion specification if you do not ground one of
the output lines.
Connecting an unbalanced load as shown in either the top or bottom
of Figure 40 ensures that the phase of the signal at the unbalanced
input matches the phase of the 764 input.
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Appendix C: Options
Analog line output XLR
Receiving equipment
unbalanced input
Pin 3 (–)
Pin 1 (shield)
Pin 2 (+)
Gnd
(+)
OR
Pin 2 (+)
(+)
Pin 3 (–)
Gnd
Pin 1 (shield)
Figure 40: Connecting to an unbalanced input
NOTE. Connecting a line to ground as shown in Figure 40 forces the
analog outputs into unbalanced mode. The outputs will clip above
approximately +20 dBu in unbalanced mode. Do not use unbalanced
mode when you have configured the instrument for either fixed high
level output or variable high level output.
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Appendix C: Options
Power Cords
Table 33 lists and describes the available power cord options. Please
contact your Tektronix representative if the power cord supplied with
your instrument is not correct for the local power supply.
Table 33: Power cord identification
Plug configuration Normal usage
Option number
North America
125V/15A Plug
NEMA 5-15P
Standard
Europe
230 V
A1
A2
United Kingdom
230 V
Australia
230 V
A3
North America
230 V
A4
A5
Switzerland
230 V
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Appendix C: Options
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Glossary
CLIP
One or more consecutive positive or negative full scale samples.
The actual number of consecutive samples that constitute a
CLIP may be adjusted through the Level Meters submenu; the
factory setting is one (1).
Copy
Output a session report via the rear-panel RS-232 port.
Frame Sync Err
Frame synchronization error between the input pair and the
reference, as a percentage of the digital audio frame.
MUTE
One or more consecutive “zero” samples. The actual number of
consecutive samples that constitute a MUTE may be adjusted
through the Level Meters submenu; the factory setting is ten (10).
nil
The measured signal level is lower than –90 dBFS
Session
A mode of instrument operation during which the digital audio
input signals are monitored, and signal data are collected.
Session Time
The time elapsed since the beginning of the current Session.
True Peak
The actual highest positive or negative audio sample value. True
Peaks will often be greater than the highest meter reading when
Extended VU or PPM ballistics are used.
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Glossary
Test Level
Also called “alignment” or “reference” level. Usually, the signal
level used for system alignment. In the 764, this setting
determines the placement of level meter markers and a meter
bar intensity/color threshold.
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Index
OFFSET, 17
A
multi-function knob, 17
PHASE DISPLAY buttons, 16
SESSION button, 16
TERM switches, 3
VIEW buttons, 16
VOLUME knob, 7, 18
Copy soft button, 30
correlation meter, 27
speed, 55
accessories, standard, 1
AGC, 28
alignment level, 43
See also test level
Audio view, 13
B
ballistics (meter), 43, 50
PPM, 43, 50
True Peak, 44, 50
VU, 44, 51
D
De-emphasis, submenu, 53
defaults, restoring, 40
digital audio inputs, 3
configuring, 10
C
display mode, 49
cable, serial communications, 62
CCIR 645, 43
Channel Status view, 15, 37
CLEAR MENU button, 18
using, 12
CLIP flag, 22
CLIPs
E
EBU R68-1992, 43
error messages. See warning
messages
flag persistence, 52
samples required, 51
Command
EXPAND button, 17
F
abbreviation, 66
syntax, 66
factory default settings, restoring,
Contacting Tektronix, xii
controls, 16
40
flow control, 58
BRIGHTNESS knob, 18
CLEAR MENU button, 18
MENU button, 10, 18
METER SCALE buttons, 17
EXPAND, 17
G
General commands, 67
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Index
Get commands, 68
interpolation (oversampling), 50
peak hold time, 51
scale, 19, 20, 22
true peak indicator, 21
Lissajous pattern, 27
H
headphones, 7
selecting channels, 48
Headphones submenu, 48, 56
M
MENU button, 10, 18
Menu commands, 70
Menu HELP messages, 10
Menus, general techniques, 10
METER SCALE buttons, 17
MUTE indicator, 21
MUTEs
message persistence, 52
samples required, 51
I
IEEE 152-1991, 44
Ignore Validity Bit, 52
Inputs
digital audio, 3
configuring, 10
LTC, 5
reference, 5
RS-232, 6
SER. VIDEO (Option 01), 89
submenu, 56
N
VITC, 5
interpolation (oversampling), 50
No Reference Signal (message),
illustrated, 32
O
K
OFFSET button, 17
Option 01, 7, 56, 89
Option 02, 4, 93
outputs
analog audio (Option 02), 93
RS-232, 6
knob icon, 10
knobs
BRIGHTNESS, 18
multi-function, 17
VOLUME, 18
VGA video, 5
L
Level Meters, submenu, 48
level meters, 18
0 dB mark, 51
ballistics, 19, 50
CLIP flag, 22
P
peak program level, 20, 51
phase display
algorithm, 46
buttons, 16
display mode, 49
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Index
channel pairing, 16
format, 26, 54
submenu, 54
PPM (meter ballistics), 43
Press commands, 70
Product Support, xii
session display, running/stopped
indicator, 30
session time, 29
Setups (saving and restoring), 40
SMPTE RP 155-90, 44
soft buttons, 11
Specifications, 75
Standby mode, 8
submenus
De-emphasis, 53
Headphones, 48, 56
Inputs, 56
Level Meters, 48
phase display, 54
Restore Setups, 40, 60
Save Setups, 40, 59
Screen Saver, 60
Serial Port, 58
R
reference inputs, 5
reference level, 44
See also test level
Remote
command abbreviation, 66
command syntax, 66
control, 6, 62, 66
RESET Session soft button, 30
Restore Setups submenu, 40, 60
RS-232 communications port, 6, 62
Service, 61
Time Code, 57
sum and difference bars, 18, 20, 25
Support
product, xii
S
service, xii
SYNC ERR Flag
illustrated, 32
Save Setups submenu, 40, 59
Screen Saver submenu, 60
Serial Port, submenu, 58
Serial video loop–through, 7
Service submenu, 61
Service Support, xii
session
Copy soft button, 30
display, 29
maximum duration, 59
reports, 34
suppress, 52
T
TERM switches, 3
test level, 20, 43, 51
Time Code
inputs, 5
submenu, 57
RESET soft button, 30
statistics, 30
time, 29
true peak indicator, turn Off, 51
SESSION button, 16
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Index
U
W
User Data view, 15, 39
warning messages
CODE ERR, 45, 84
Interpolation OFF, 50
LOW CONF, 45, 85
MUTE, 21
NO INPUT, 44, 85, 86
No Video Input, 92
NOT PRESENT, 93
PARITY, 45, 87
V
Validity Bit, ignore, 52
VGA video output, 5
VIEW buttons, 16
Views
Audio, 13
Channel Status, 15
User Data, 15
SYNC ERR, 32, 52
V BIT, 46, 88
VOLUME knob, 18
VU (meter ballistics), 44
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