Agilent U2761A
USB Modular
Function/Arbitrary
Waveform Generator
User’s Guide
Agilent Technologies
Safety Symbols
The following symbols on the instrument and in the documentation
indicate precautions which must be taken to maintain safe operation of
the instrument.
Direct current (DC)
Equipment protected throughout by
double insulation or reinforced
insulation
Alternating current (AC)
Off (supply)
Both direct and alternating current
On (supply)
Three-phase alternating current
Earth (ground) terminal
Caution, risk of electric shock
Caution, risk of danger (refer to this
manual for specific Warning or Caution
information)
Protective conductor terminal
Caution, hot surface
Frame or chassis terminal
Equipotentiality
Out position of a bi-stable push control
In position of a bi-stable push control
U2761A User’s Guide
III
General Safety Information
The following general safety precautions must be observed during all
phases of operation of this instrument. Failure to comply with these
precautions or with specific warnings elsewhere in this manual violates
safety standards of design, manufacture and intended use of the
instrument. Agilent Technologies Inc. assumes no liability for the
customer’s failure to comply with these requirements.
• Do not operate the product in an explosive atmosphere or in the
presence of flammable gases or fumes.
• Do not use the equipment if it does not operate properly. Have the
equipment inspected by qualified service personnel(s).
WARNING
CAUTION
• Observe all markings on the instrument before connecting any wiring to
the instrument.
• Use the device with the cables provided.
• Repair or service that is not covered in this manual should only be
performed by qualified personnel(s).
IV
U2761A User’s Guide
Environment Conditions
This instrument is designed for indoor use and in the area with low
condensation. The table below shows the general environmental
requirements for this instrument.
Environment conditions Requirements
Operating temperature
Operating humidity
Storage temperature
Storage humidity
0 °C to 50 °C
20 to 85% RH non-condensing
–20 °C to 70 °C
5 to 90% RH non-condensing
The U2761A USB modular function/arbitrary waveform generator
complies with the following safety and EMC requirements.
CAUTION
•
IEC 61010-1:2001/EN61010-1:2001 (2nd Edition)
Canada: CAN/CSA-C22.2 No. 61010-1-04
USA: ANSI/UL 61010-1:2004
IEC 61326-2002/EN 61326:1997+A1:1998+A2:2001+A3:2003
Canada: ICES-001:2004
•
•
•
•
•
Australia/New Zealand: AS/NZS CISPR11:2004
U2761A User’s Guide
V
Regulatory Markings
The CE mark is a registered trademark
The C-tick mark is a registered
trademark of the Spectrum
of the European Community.This CE
mark shows that the product complies
with all the relevant European Legal
Directives.
Management Agency of Australia.
This signifies compliance with
the Australia EMC Framework
regulations under the terms of the
Radio Communication Act of 1992.
ICES/NMB-001 indicates that this
ISM device complies with Canadian
ICES-001.
Cet appareil ISM est confomre a la
norme NMB-001 du Canada.
This instrument complies with the
WEEE Directive (2002/96/EC)
marking requirement. This affixed
product label indicates that you must
not discard this electrical/electronic
product in domestic household waste.
The CSA mark is a registered
trademark of the Canadian Standards
Association.
VI
U2761A User’s Guide
Waste Electrical and Electronic Equipment (WEEE) Directive
2002/96/EC
This instrument complies with the WEEE Directive (2002/96/EC) marking
requirement. This affixed product label indicates that you must not discard
this electrical/electronic produc
U2761A User’s Guide
VII
St
anda
rd
L
im
it
Declaration of Conformity
DECLARATION OF CONFORMITY
According to EN ISO/IEC 17050-1:2004
Generic example
Manufacturer’s Name:
Manufacturer’s Address:
Agilent Technologies Microwave Products (M) Sdn. Bhd
Bayan Lepas Free Industrial Zone,
11900, Bayan Lepas, Penang, Malaysia
Declares under sole responsibility that the product as originally delivered
Product Name:
Models Number:
Product Options:
Agilent USB Modular Function Generator
U2761A
This declaration covers all options of the above product(s)
complies with the essential requirements of the following applicable European Directives, and
carries the CE marking accordingly:
Low Voltage Directive (2006/95/EC)
EMC Directive (2004/108/EC)
and conforms with the following product standards:
EMC
IEC 61326:2002 / EN 61326:1997+A1:1998+A2:2001+A3:2003
CISPR 11:1990 / EN55011:1990
Class A Group 1
4 kV CD, 8 kV AD
3 V/m, 80-1000 MHz
0.5 kV signal lines, 1 kV power lines
0.5 kV line-line, 1 kV line-ground
3 V, 0.15-80 MHz
IEC 61000-4-2:1995 / EN 61000-4-2:1995
IEC 61000-4-3:1995 / EN 61000-4-3:1996
IEC 61000-4-4:1995 / EN 61000-4-4:1995
IEC 61000-4-5:1995 / EN 61000-4-5:1995
IEC 61000-4-6:1996 / EN 61000-4-6:1996
IEC 61000-4-11:1994 / EN 61000-4-11:1994
1 cycle / 100%
Canada: ICES-001:2004
Australia/New Zealand: AS/NZS CISPR11:2004
The product was tested in a typical configuration with Agilent Technologies test systems.
IEC 61010-1:2001 / EN 61010-1:2001
Canada: CAN/CSA-C22.2 No. 61010-1-04
USA: ANSI/UL 61010-1:2004
Safety
206349
This DoC applies to above-listed products placed on the EU market after:
08-Jan-2008
Date
Tay Eng Su
Quality Manager
For further information, please contact your local Agilent Technologies sales office, agent or distributor,
or Agilent Technologies Deutschland GmbH, Herrenberger Straße 130, 71034 Böblingen, Germany.
Template: A5971-5302-2, Rev. E
U2761A
DoC Revision 1.0
VIII
U2761A User’s Guide
Product Regulations
EMC
Performance Criteria
IEC 61326-1:2002 / EN 61326-1:1997+A1:1998+A2:2001+A3:2003
CISPR 11:1990 / EN 55011:1990 – Group 1 Class A
IEC 61000-4-2:1995 / EN 61000-4-2:1995 (ESD 4kV CD, 8kV AD)
IEC 61000-4-3:1995 / EN 61000-4-3:1996 (3V/m, 80% AM)
IEC 61000-4-4:1995 / EN 61000-4-4:1995 (EFT 0.5kV line-line, 1kV line-earth)
IEC 61000-4-5:1995 / EN 61000-4-5:1995 (Surge 0.5kV line-line, 1kV line-earth)
IEC 61000-4-6:1996 / EN 61000-4-6:1996 (3V, 0.15~80 MHz, 80% AM, power line)
IEC 61000-4-11:1994 / EN 61000-4-11:1994 (Dips 1 cycle, 100%)
Canada: ICES-001:2004
A
A
B
A
A
A
Australia/New Zealand: AS/NZS CISPR11:2004
IEC 61010-1:2001 / EN 61010-1:2001
Safety
Canada: CAN/CSA-C22.2 No. 61010-1-04
USA: ANSI/UL 61010-1:2004
Additional Information:
The product herewith complies with the essential requirements of the Low Voltage Directive 2006/95/EC and the
EMC Directive 2004/108/EC and carries the CE Marking accordingly (European Union).
1Performance Criteria:
A Pass - Normal operation, no effect.
B Pass - Temporary degradation, self recoverable.
C Pass - Temporary degradation, operator intervention required.
D Fail - Not recoverable, component damage.
N/A – Not applicable
Notes:
Regulatory Information for Canada
ICES/NMB-001:2004
This ISM device complies with Canadian ICES-001.
Cet appareil ISM est confomre à la norme NMB-001 du Canada.
Regulatory Information for Australia/New Zealand
This ISM device complies with Australian/New Zealand AS/NZS CISPR11:2004
U2761A User’s Guide
IX
In This Guide…
1
2
3
Getting Started
In this chapter, you prepare your system for installation and configuration
to get started with the U2761A.
Features and Functions
In this chapter, you will learn about the functions and features offered by
the U2761A.
Characteristics and Specifications
In this chapter, you will observe the product characteristics and
specifications.
X
U2761A User’s Guide
Contents
1
Getting Started
Product at a Glance
Standard Purchase Items
5
6
Initial Inspection
E. Connect the Module to Your PC 15
55-Pin Backplane Connector Pin Configuration 23
Chassis Installation 24
2
Features and Functions 25
Output Configuration 26
Introduction 26
Output Function 26
U2761A User's Guide
XI
Output Termination 36
Pulse Waveform 45
Carrier Frequency 51
Carrier Frequency 57
Modulating Waveform Frequency 59
Frequency Deviation 59
Generate FM Using SCPI Commands 60
Phase Modulation (PM) 61
XII
U2761A User's Guide
Carrier Frequency 63
To Select FSK Modulation 66
Carrier Waveform 72
To Select ASK Modulation 76
Frequency Sweep 80
To Select Sweep 80
Start Frequency and Stop Frequency 81
Sweep Mode 82
Sweep Time 82
U2761A User's Guide
XIII
Triggering 85
Manual Triggering 86
Set Triggering Using SCPI Commands 90
Arbitrary Waveforms 91
3
Product Characteristics 96
Product Specifications and Characteristics 97
Index 103
XIV
U2761A User's Guide
List of Figures
Figure 2-25 ASK modulation waveform 76
Figure 2-26 Panel view of ASK 77
Figure 2-27 Frequency sweep 80
Figure 2-28 Panel view of sweep 81
Figure 2-29 Trigger input pulse 88
U2761A User’s Guide
XV
Figure 2-30 Trigger output pulse 88
Figure 2-31 Ramp waveform 91
Figure 2-32 Waveform download in progress 93
XVI
U2761A User’s Guide
List of Tables
Table 2-5 Carrier frequency for PM 63
Table 2-6 Carrier frequency for FSK 68
Table 2-7 “Hop” frequency 69
Table 2-8 Carrier frequency for PSK 73
Table 2-9 Carrier frequency for ASK 78
U2761A User’s Guide
XVII
XVIII
U2761A User’s Guide
Agilent U2761A USB Modular Function/Arbitrary Waveform Generator
User’s Guide
1
Product at a Glance
Product Dimensions
3
5
Standard Purchase Items
7
Inspection and Maintenance
Installation and Configuration
8
9
This chapter provides the introduction of the U2761A that
helps you get acquainted with the product and the product
outlook. This chapter also includes the installation and
configuration procedures that will help you get started with
the U2761A.
Agilent Technologies
1
1
Getting Started
Introduction
The U2761A is a 20 MHz USB modular function generator
with Arbitrary waveform and pulse generation capabilities. It
can operate as a standalone unit or as part of a modular
unit when used with the U2781A USB modular instrument
chassis.
The U2761A adopts the latest direct digital synthesis (DDS)
technology that digitally creates Arbitrary waveforms and
frequencies from a single, fixed source frequency. DDS offers
the precision of a digital control logic; reducing the
complexity of the generator while increasing the stability.
Thus, creating a stable, accurate output signal for clean, low
distortion sine waves with fast rise and fall time up to
20 MHz and linear Ramp waves up to 200 kHz.
Various features of the U2761A
• 20 MHz Sine and Square waveforms
• Hi-Speed 2.0, USBTMC 488.2 standards
• Sine, Square, Ramp, Triangle, Pulse, and DC waveforms
• 14-bit, 50 MSa/s, 64 K-point Arbitrary waveforms
• AM, FM, PM, ASK, FSK, and PSK modulation types
• 40 mVpp to 5 Vpp amplitude range for 50 Ω load, and
80 mVpp to 10 Vpp amplitude range for open circuit
• Pulse generation
2
U2761A User’s Guide
1
Getting Started
Front View
USB indicator
Power indicator
10 MHz reference connector
Trigger in connector
Output connector
Trigger out connector
Rear View
Fan Ventilation
55-pin backplane connector
USB inlet
Fastening hole for USB cable with locking mechanism
Power inlet
4
U2761A User’s Guide
Getting Started
1
Standard Purchase Items
Verify the following items for the standard purchase of the
U2761A. If there are any missing or mechanically damaged
items, contact the nearest Agilent Sales Office.
✔ 12 V, 2 A AC/DC power adapter
✔ Power cord
✔ USB Standard-A to Mini-B interface cable
✔ L-Mount kit (used with modular instrument chassis)
✔ Agilent Automation-Ready CD (contains the IO Libraries
Suite)
✔ Agilent USB Modular Products Quick Start Guide
✔ Agilent USB Modular Products Reference CD-ROM
✔ Agilent Measurement Manager Quick Reference Card
✔ Certificate of Calibration
U2761A User’s Guide
7
1
Getting Started
Inspection and Maintenance
Initial Inspection
When you receive your U2761A, inspect the unit for any
obvious damage such as broken terminals or cracks, dents,
and scratches on the casing that may occur during shipment.
If any damage is found, notify the nearest Agilent Sales
Office immediately. The front of this manual contains the
warranty information.
Keep the original packaging in case the U2761A has to be
returned to Agilent in the future. If you return the U2761A
for service, attach a tag identifying the owner and model
number. Also include a brief description of the problem.
Electrical Check
The U2761A USB Modular Function/Arbitrary Waveform
Generator Service Guide will provide the complete
verification and calibration procedures. The procedures will
verify to a high level of confidence that the U2761A is
operating in accordance with its specifications.
General Maintenance
Any repair that is not covered in your modular product manuals should
only be performed by qualified personnel.
NOTE
1 Power off your module and remove the power cord and
I/O cable from your device.
2 Remove your module from the bumper casing.
3 Shake off any dirt that may have accumulated on the
module.
4 Wipe your module with a dry cloth and install the
bumper back in place.
8
U2761A User’s Guide
Getting Started
1
Installation and Configuration
Installation
Follow the step-by-step instructions shown in the following
flowchart to get started with the preparations and
installations of your U2761A.
with Agilent VEE Pro, LabVIEW, or Microsoft Visual Studio .
NOTE
®
A. Check Your System
F. Verify Your Module Connection
G. Launch Your Agilent Measurement Manager
U2761A User’s Guide
9
1
Getting Started
A. Check Your System
Prior to any installation or configuration, please ensure that
your PC meets the following minimum system requirements.
Processor 1.6 GHz Pentium® IV or higher
Operating system Windows® XP Professional or Home Edition
(Service Pack 1 or later), or Windows® 2000 Professional
(Service Pack 4 or later)
Browser Microsoft® Internet Explorer 5.01 or higher
Available RAM 512 MB or higher recommended
Hard-disk space 1 GB
Video Super VGA 800×600 (1024×768 recommended)
Prerequisites Agilent IO Libraries Suite 14.2 or higher
1
(version 15.0 recommended), Agilent T&M Toolkit Runtime
2
version 2.1 , Agilent T&M Toolkit Redistributable Package 2.1
2
2
patch , Microsoft® .NET Framework version 1.1 and 2.0
1 Available on Agilent Automation-Ready CD.
2 Bundled with Agilent Measurement Manager application software installer.
10
U2761A User’s Guide
Getting Started
1
B. Install the IO Libraries Suite
The IO Libraries Suite 14.2 or higher is available on the
Agilent Automation-Ready CD that comes with the standard
purchase of the U2761A.
•
•
If you do not have the Agilent Automation-Ready CD, obtain the IO
Libraries Suite 14.2 or higher at http://www.agilent.com/find/iolib.
NOTE
Disconnect any USB instruments or connectivity interface from your
PC.
1 Close all other applications on your PC, insert the Agilent
Automation-Ready CD into your CD-ROM drive, and follow
the instructions on your screen.
2 If the IO Libraries Suite installation does not start
automatically, go to Start > Run (on the Windows Start
menu) and type <drive>:\autorun\auto.exe where
<drive>is your CD-ROM drive location.
3 If you obtain the IO Libraries Suite from the web, save
the self-extracting zip file (*.exe) to any location on your
hard disk.
4 Double-click the installation file to launch the installation.
5 Follow the instructions on your screen to proceed with
the installation.
6 After the installation has completed, you will see the IO
Control icon on the Windows taskbar notification area as
shown below.
For detailed installation instructions, refer to the Agilent IO Libraries Suite
Getting Started Guide at http://www.agilent.com/find/iolib.
NOTE
U2761A User’s Guide
11
1
Getting Started
C. Install the Module Driver
installing the driver.
NOTE
1 Verify that your PC meets the minimum system
requirements as stated in “A. Check Your System” on
page 10.
2 Insert the Product Reference CD-ROM into your CD-ROM
drive.
3 The installer will automatically launch the Agilent Modular
Products Installation Menu. Click Hardware Driver to begin the
installation.
4 If the menu does not launch automatically, go to Start >
Run (on the Windows Start menu) and type <drive>:\
Driver\Hardware\setup_Hw.exe where <drive>is
your CD-ROM drive location. Click OK to begin the
installation.
5 Follow the instructions on the screen and click Next to
proceed.
12
U2761A User’s Guide
Getting Started
1
6 Click Install to begin the installation. Follow the
instructions on the screen to proceed with the
installation.
D. Install the Agilent Measurement Manager
1 If you have done “C. Install the Module Driver” on
page 12, proceed to Step 2. If not, close all other
applications on your PC and insert the Product Reference
CD-ROM into your CD-ROM drive.
2 Click Measurement Manager on the U2761A Installation Menu to
begin the installation.
3 If the installation menu does not appear after a few
seconds, go to Start > Run and type <drive>:\
Application\Modular Instruments Measurement
Manager\setup.exe where <drive> is your CD-ROM
drive location.
4 Click OK to begin the installation.
5 If you do not have any of the prerequisites installed, the
InstallShield Wizard software prerequisite will appear.
U2761A User’s Guide
13
1
Getting Started
6 Click OK to begin the installation of the listed missing
prerequisites.
7 Once the above installation has completed, installation of
the Measurement Manager software will proceed as
normal.
8 The Measurement Manager InstallShield Wizard dialog will
appear. Click Next to begin.
9 Read the License Agreement and select I accept the terms in
the License Agreement to proceed. You may click Print to
print a hardcopy of the Agilent License Terms for
reference. Click Next to proceed.
10 Fill in the Customer Information Form accordingly and
click Next.
11 Click Next to install to the specified folder or click Change
to install to a different folder.
12 Click Install to begin the installation of the Measurement
Manager.
13 Click Finish when the installation has completed.
14 A shortcut to this software will be created on your
desktop.
USING THE LICENSED MATERIALS INDICATES YOUR ACCEPTANCE OF
THE LICENSE TERMS. IF YOU DO NOT AGREE TO ALL OF THESE TERMS,
YOU MAY RETURN ANY UNOPENED LICENSED MATERIAL FOR A FULL
REFUND. IF THE LICENSED MATERIALS ARE BUNDLED OR PRELOADED
WITH ANOTHER PRODUCT, YOU MAY RETURN THE ENTIRE UNUSED
PRODUCT FOR A FULL REFUND.
NOTE
using
14
U2761A User’s Guide
Getting Started
1
E. Connect the Module to Your PC
Ensure that the Agilent Measurement Manager is installed before
proceeding.
NOTE
1 After the installations have completed, connect the power
cord to the AC/DC power adapter. The AC/DC power
adapter requirements are 100 to 240 VAC, 50/60 Hz, with
an output voltage of +12 VDC.
2 Insert the DC output plug from the AC/DC power adapter
to the power jack on the rear panel of the U2761A.
3 Connect the U2761A to any USB port on your PC with
the bundled USB cable.
4 Your PC will automatically detect the connected unit and
the Found New Hardware Wizard window will appear. Select
Yes, this time only and click Next to proceed.
U2761A User’s Guide
15
1
Getting Started
5 Select Install the software automatically (Recommended) and
click Next.
6 A warning message will appear on the Hardware Installation
window. Click Continue Anyway to proceed with the
installation of the U2761A.
16
U2761A User’s Guide
Getting Started
1
If you do not wish to receive similar warning messages in the future,
follow the instructions below.
NOTE
•
•
Go to Start > Control Panel and double-click System.
Select the Hardware tab and click Driver Signing on the Drivers panel.
The Driver Signing Options dialog box will appear.
•
Select Ignore to disable the warning message.
7 Click Finish to complete the installation.
U2761A User’s Guide
17
1
Getting Started
8 The Assign USB device alias window will appear. Each time
the U2761A is plugged in, this dialog box will appear. To
disable this dialog, select the Never show this dialog option
in the Show this dialog panel and click OK.
9 For modules other than the U2300A Series, U2500A
Series, U2600A Series, and U2781A, the system will
perform a firmware version check on your connected
module.
a If the module firmware version is the same as the
installed version on the PC, it will not perform any
firmware download and the U2761A is now ready for
use.
b If the module firmware version differs from the
installed version on the PC, the following message box
will appear. Firmware versions (V1.00 and V1.01) in the
figure are for illustration purpose only, it might vary
depending on the device and PC firmware version.
18
U2761A User’s Guide
Getting Started
1
c Click Yes to begin the firmware download. The
following message box will appear indicating the
download in progress.
Ensure that you do not remove the USB and power connection until the
firmware download has completed.
NOTE
d Your U2761A is ready for use once the firmware
download has completed.
F. Verify Your Module Connection
The Agilent Connection Expert is one of the utilities in the
IO Libraries. The Connection Expert configures the
connected instruments and enables communication. It is able
to automatically detect the U2761A devices plugged into the
PC.
1 Go to Start > All Programs > Agilent IO Libraries Suite > Agilent
Connection Expert to launch the Connection Expert.
2 The detected U2761A will be visible on the Instrument I/O
on this PC explorer pane. Right-click on the U2761A
instrument on the explorer pane.
U2761A User’s Guide
19
1
Getting Started
3 A context menu will appear as shown below and select
Send Commands To This Instrument.
4 The Agilent Interactive IO dialog box will appear. Click Send &
Read to send the *IDN? default command. The
instrument’s response should appear in the Instrument
Session History panel.
5 If the Connection Expert can successfully communicate
with the U2761A, this indicates that the instrument is
installed correctly.
20
U2761A User’s Guide
Getting Started
1
G. Launch Your Agilent Measurement Manager
•
•
The IO Control will launch automatically when you start your PC.
NOTE
Launching the Measurement Manager without the IO Control running
will cause failure of the Measurement Manager to detect or establish
any connection with the U2761A connected to your PC.
•
To run the IO Control, go to Start > All Programs > Agilent IO
Libraries Suite > Utilities > IO Control.
1 Double-click the Measurement Manager software icon on
your desktop or go to Start > All Programs > Agilent > Modular
Products > Agilent Measurement Manager to launch the
software.
2 The Measurement Manager welcome screen will appear.
U2761A User’s Guide
21
1
Getting Started
3 The Select USB Device dialog box will appear displaying the
connected U2761A devices. To start the application, select
a U2761A device and click OK to establish the connection.
For more information on how to use the Measurement Manager, refer to
the Agilent Measurement Manager help file.
NOTE
22
U2761A User’s Guide
Getting Started
1
55-Pin Backplane Connector Pin Configuration
The 55-pin backplane connector is used when the U2761A
module is inserted into the U2781A USB modular instrument
chassis. For more details, refer to the Agilent U2781A USB
Modular Instrument Chassis User's Guide.
GND
NC
GND
NC
GND
NC
GND
NC
GND GND
NC NC
GND
NC
GND GND
NC VBUS
GND
GND
GND
GND
USB_D–
USB_D+
GND
F
E
GND TRIG3
TRIG4 GND
GND
TRIG5
TRIG2
GND
GND TRIG1 GND TRIG0 GND
D
C
B
A
TRIG6 GND TRIG7 GND +12 V +12 V
nBPUB CLK10M GND STAR_TRIG GA2
GA1
NC
6
GA0
NC
5
NC +12 V +12 V
NC +12 V +12 V
+12 V
+12 V
1
NC
NC
NC
NC
NC
11
10
9
8
7
4
3
2
Figure 1-1 55-pin backplane connector pin configuration
Table 1-1 Synchronous Simultaneous Interface (SSI) connector pin
description
SSI timing signal
GND
Functionality
Ground
NC
Not connected
VBUS
USB bus power sensing input
USB differential pair
Trigger bus
USB_D+, USB_D–
TRIG0~TRIG7
+12 V
+12 V power with 4 A current
USB backplane input detect
10 MHz clock source
Star trigger
nBPUB
CLK10M
STAR_TRIG
GA0,GA1,GA2
Geographical address pin
U2761A User’s Guide
23
1
Getting Started
Chassis Installation
The L-mount kit is to be installed to your U2761A module.
The following instructions describe the simple procedure of
installing the L-mount kit and your module in the U2781A
chassis.
1 Unpack the L-mount kit from its packaging.
2 Remove your U2761A module from the bumper casing.
3 Using a Phillips screwdriver, fasten the L-Mount kit to
your U2761A module.
4 Insert your U2761A module into the U2781A chassis with
the 55-pin backplane connector positioned at the bottom
of the module.
5 Once you have slotted the module into the chassis, tighten
the screws of the L-mount kit to secure the connection.
24
U2761A User’s Guide
Agilent U2761A USB Modular Function/Arbitrary Waveform Generator
User’s Guide
2
Phase-Shift Keying (PSK) Modulation 71
Amplitude-Shift Keying (ASK) Modulation 76
Frequency Sweep 80
Triggering 85
Arbitrary Waveforms 91
In this chapter, you will learn about the functions and
features offered by the U2761A.
Agilent Technologies
25
2
Features and Functions
Output Configuration
Introduction
This section contains the information to help you configure
the U2761A for outputting waveforms. You may not need to
change some of the parameters discussed here, but they are
provided so that you will have accessibility when needed.
Output Function
The U2761A can output five standard waveforms (Sine,
Square, Ramp, Triangle, and Pulse), and DC. You can select
one of the three built-in Arbitrary waveforms or create your
own custom waveforms. In addition, you can internally
modulate Sine, Square, Ramp, Triangle, and Arbitrary
waveforms using AM, FM, PM, FSK, PSK, or ASK. The linear
or logarithmic frequency sweeping is available for Sine,
Square, Ramp, Triangle, and Arbitrary waveforms.
The table below shows which output functions are allowed
with modulation and sweep. Each “V” indicates a valid
combination. If you change to a function that is not
applicable for modulation, or sweep; then the modulation or
mode will be disabled.
Table 2-1 Output functions
Sine
V
Square
Ramp
Triangle
Pulse
DC
Arbitrary
AM, FM, PM, FSK, PSK, ASK Carrier
AM, FM, PM Internal Modulation
FSK, PSK, ASK Internal Modulation
Sweep Mode
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
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Function Limitation
If you change to a function where the maximum frequency is
less than the current function, the frequency will be
adjusted to the maximum value for the new function.
For example, if you are currently outputting a 20 MHz sine
wave and then change to the Ramp function, the U2761A
will automatically adjusts the output frequency to 200 kHz
(the upper limit for Ramp).
Amplitude Limitation
If you change to a function where the maximum amplitude
is less than the current function, the amplitude will
automatically be adjusted to the maximum value for the new
function. This may occur when the output units are Vrms or
dBm due to the differences in crest factor for the various
output functions.
For example, if you output a 2.5 Vrms Square wave (into
50 Ω) and then change to the Sine wave function, the
U2761A will automatically be adjusted the output amplitude
to 1.768 Vrms (the upper limit for Sine wave in Vrms).
U2761A User’s Guide
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Features and Functions
2
To select a function, click any of the functions on the top
panel as shown below. When a function is selected, the
button will be illuminated.
Figure 2-2 Top panel view of the U2761A
Click Arb
to output the Arbitrary waveform. Select
other Arbitrary waveform choices from the drop down list
.
Remote Interface Operation
FUNCtion {SINusoid|SQUare|RAMP|PULSe|DC|USER}
You can also use the APPLy command to select the function,
frequency, amplitude, and offset.
Output Frequency
As shown below, the output frequency range depends on the
function currently selected. The default frequency is 1 kHz for
all functions.
Table 2-2 Output frequency range
Function
Sine
Minimum frequency
1 μHz
Maximum frequency
20 MHz
Square
Ramp, Triangle
Pulse
1 μHz
20 MHz
1 μHz
200 kHz
500 μHz
5 MHz
DC
Not applicable
1 μHz
Not applicable
200 kHz
Arbitrary
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2
Features and Functions
Function Limitations
If you change to a function where the maximum frequency is
less than the current function, the frequency will be
adjusted to the maximum value for the new function.
For example, if you are currently outputting a 20 MHz sine
wave and then change to the Ramp function, the U2761A
will automatically adjusts the output frequency to 200 kHz
(the upper limit for Ramp).
Duty Cycle Limitations
For Square waveforms, the U2761A may not be able to use
the full range of duty cycle values at higher frequencies as
shown below.
• 20% to 80% (frequency ≤ 10 MHz)
• 40% to 60% (frequency > 10 MHz)
If you change to a frequency that cannot produce the
current duty cycle, the duty cycle is automatically adjusted
to the maximum value for the new frequency.
For example, if you currently have the duty cycle set to 70%
automatically adjusts the duty cycle to 60% (the upper limit
for this frequency).
Soft Front Panel Operation
On the Frequency panel as shown in Figure 2-3, input the
desired frequency value and select the unit from the drop
down list. To set the waveform period instead, select Period
.
Figure 2-3 Panel view of the frequency section
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Remote Interface Operation
FREQuency <frequency>
You can also use the APPLy command to select the function,
frequency, amplitude, and offset.
Output Amplitude
The default amplitude is 1 Vpp (into 50 Ω) for all functions.
Offset Voltage Limitations
The relation between the output amplitude and offset voltage
is shown below. Vmax is the maximum peak voltage for the
selected output termination (5 V for a 50 Ω load or 10 V for
a high-impedance load).
V
≤ 2 × (V
– V
offset
)
pp
max
Limits Due to Output Termination
If you change the output termination setting, the value of
the output amplitude will be adjusted (and no error will be
generated).
For example, if you set the amplitude to 5 Vpp and then
change the output termination from 50 Ω to “high
impedance”, the amplitude value will double to 10 Vpp. If
you change from “high impedance” to 50 Ω, the displayed
amplitude value will drop to half. For more information, see
“Output Termination” on page 36.
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2
Features and Functions
Limits Due to Units Selection
In some cases, the amplitude limits are determined by the
output units selected. This may occur when the units are
Vrms or dBm due to the differences in crest factor for the
various output functions.
For example, if you output a 2.5 Vrms Square wave (into
50 Ω) and then change to the Sine wave function, the
U2761A will automatically adjusts the output amplitude to
1.768 Vrms (the upper limit for Sine wave in Vrms).
You can set the output amplitude in Vpp, Vrms, or dBm. For
You cannot specify the output amplitude in dBm if the
output termination is set to “high impedance”.
Soft Front Panel Operation
On the Amplitude panel as shown in Figure 2-4, input the
desired amplitude value and select the unit from the drop
down list.
Figure 2-4 Panel view of the amplitude section
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Remote Interface Operation
VOLTage <amplitude>
Or, you can set the amplitude by specifying a high level and
low level using the following commands.
VOLTage:HIGH <voltage>
VOLTage:LOW <voltage>
You can also use the APPLy command to select the function,
frequency, amplitude, and offset.
DC Offset Voltage
The default offset is 0 V for all functions.
Limits Due to Amplitude
The relation between the offset voltage and output amplitude
is shown below. Vmax is the maximum peak voltage for the
selected output termination (5 V for a 50 Ω load or 10 V for
a high-impedance load).
V
pp
--------
V
≤ V
–
offset
max
2
If the specified offset voltage is not valid, the U2761A will
automatically adjusts it to the maximum DC voltage allowed
with the specified amplitude.
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2
Features and Functions
Soft Front Panel Operation
On the Offset panel as shown in Figure 2-5, input the
desired offset value and select the unit from the drop down
list.
Figure 2-5 Panel view of the DC offset section
Remote Interface Operation
VOLTage:OFFSet <offset>
Or, you can set the offset by specifying a high level and low
level using the following commands.
VOLTage:HIGH <voltage>
VOLTage:LOW <voltage>
You can also use the APPLy command to select the function,
frequency, amplitude, and offset.
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Output Units
This configuration applies to output amplitude only. At
power-on, the units for output amplitude are volts
peak-to-peak.
• The output units consist of Vpp, Vrms, or dBm. The
default unit is Vpp.
• The unit setting is stored in volatile memory. The units
are set to “Vpp” upon power-off or after a remote
interface reset.
• The output units for amplitude cannot be set to dBm if
the output termination is currently set to
“high impedance”. The units are automatically converted
to Vpp.
Soft Front Panel Operation
On the Amplitude panel as shown in Figure 2-4, input the
desired amplitude value and select the unit from the drop
down list.
Remote Interface Operation
VOLTage:UNIT {VPP|VRMS|DBM}
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2
Features and Functions
Output Termination
This configuration applies to output amplitude and offset
voltage only. The U2761A has a fixed series output
impedance of 50 Ω to the device output connector. If the
actual load impedance is different from the specified value,
the amplitude and offset levels will be incorrect.
• The range of the output termination is 1 Ω to 10 kΩ, or
Infinite. The default value is 50 Ω.
• The output termination setting is stored in volatile
memory and upon power-off or after a remote interface
reset, the setting will return to a default value.
• If you specify a 50 Ω termination but are actually
terminating into an open circuit, the actual output will be
twice the value specified.
For example, if you set the offset to 100 mVDC (and
specify a 50 Ω load) but are terminating the output into
an open circuit, the actual offset will be 200 mVDC.
• If you change the output termination setting, the output
amplitude and offset levels are automatically adjusted (no
error will be generated).
For example, if you set the amplitude to 5 Vpp and then
change the output termination from 50 Ω to “high
impedance”, the amplitude value will double to 10 Vpp. If
you change from “high impedance” to 50 Ω, the displayed
amplitude value will drop to half.
• You cannot specify the output amplitude in dBm if the
output termination is currently set to “high impedance”.
The units are automatically converted to Vpp.
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Soft Front Panel Operation
Click Tools and select Waveform Gen as shown in the following.
Figure 2-6 Panel view of the Tools menu
Then, select the Output Setup tab, input the desired load
impedance value on the Impedance Load panel and select
the unit from the drop down list, or select High Z
for
high impedance load.
Remote Interface Operation
OUTPut:LOAD {<ohms>|INFinity}
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2
Features and Functions
Duty Cycle (Square Waves)
The duty cycle of a Square wave represents the amount of
time per cycle that the Square wave is at a high level
(assuming that the waveform is not inverted).
20% Duty Cycle
80% Duty Cycle
Figure 2-7 Square wave duty cycles
Refer to “Pulse Waveform” on page 45 for the information on
the duty cycle for Pulse waveforms.
Duty Cycle
• 20% to 80% (frequency ≤ 10 MHz)
• 40% to 60% (frequency > 10 MHz)
The duty cycle is stored in volatile memory where the duty
cycle is set to default 50% upon power-off or after a remote
interface reset.
The duty cycle setting is stored when you change from
Square wave to another function. Thus, when you return to
the Square function, the previous duty cycle is used.
Limits Due to Frequency
If the Square wave function is selected and you change to a
frequency that cannot produce the current duty cycle, the
duty cycle is automatically adjusted to the maximum value
for the new frequency.
For example, if you currently have the duty cycle set to 70%
and then change the frequency to 12 MHz, the U2761A will
automatically adjusts the duty cycle to 60% (the upper limit
for this frequency).
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The duty cycle setting does not apply to a Square waveform
used as the modulating waveform for AM, FM, or PM. A 50%
duty cycle is always used for a modulating Square waveform.
carrier.
Soft Front Panel Operation
After selecting Square
at the top panel as shown in
Figure 2-2, on the Duty Cycle panel below, input the desired
duty cycle value.
Figure 2-8 Panel view of the duty cycle section
Remote Interface Operation
FUNCtion:SQUare:DCYCle <percent>
The APPLy command automatically sets the duty cycle to
50%.
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2
Features and Functions
Symmetry (Ramp Wave)
This configuration applies to Ramp wave only. Symmetry
represents the amount of time per cycle that the Ramp wave
is rising (assuming that the waveform is not inverted).
0% Symmetry
100% Symmetry
Figure 2-9 Ramp wave duty cycles
• The symmetry percentage is stored in volatile memory
where the symmetry is set to default 100% upon power-off
or after a remote interface reset.
• The symmetry setting is stored when you change from
Ramp wave to another function. Thus, when you return to
the Ramp function, the previous symmetry is used.
• If you select a Ramp waveform as the modulating
not apply.
Soft Front Panel Operation
After selecting Ramp
at the top panel as shown in
Figure 2-2, on the Symmetry panel below, input the desired
symmetry value.
Figure 2-10 Panel view of the symmetry section
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Remote Interface Operation
FUNCtion:RAMP:SYMMetry <percent>
The APPLy command automatically sets the symmetry to
100%.
Output Control
You can disable or enable the soft front panel output
control. By default, the output is disabled at power-on. When
enabled, the Output button is illuminated.
If an excessive external voltage is applied to the device
output connector, the output will be disabled. To re-enable
and click Output
to enable the output.
Soft Front Panel Operation
Click Output
to enable or disable the output as shown
in Figure 2-11.
Figure 2-11 Panel view of the output section
U2761A User’s Guide
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2
Features and Functions
Remote Interface Operation
OUTPut {0|OFF|1|ON}
The APPLy command overrides the current setting and
automatically enables the output control.
Set Output Using SCPI Commands
The following SCPI commands show a sample procedure of
generating output.
Example 1, To output a DC voltage
-> *CLS; *RST
//To reset the U2761A to default
power-on state, this command
can be ignored if this operation
is not required.
-> FUNC DC
//Sets the output to DC.
-> VOLT:OFFS 1
//Sets the output DC offset voltage
to 1 VDC.
-> OUTP:LOAD INF
-> OUTP ON
//Changes the output termination
to infinity.
//Turns on output.
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Example 2, To output a Sine wave
-> *CLS; *RST
//To reset the U2761A to default
power-on state, this command can
be ignored if this operation is not
required.
-> FUNC SIN
-> VOLT 5 VPP
-> FREQ 1000
-> VOLT:OFFS 0
-> OUTP ON
//Sets the output to Sine wave.
//Sets the output amplitude to 5 Vpp.
//Sets the output frequency to 1 kHz.
//Sets the output offset to 0.
//Turns on output.
Example 3, To output a Square wave
-> *CLS; *RST
//To reset the U2761A to
default power-on state,
this command can be
ignored if this operation
is not required.
-> APPL:SQU 2000,5 VPP,0 //Sets the output to Square
wave, frequency 2 kHz,
amplitude
5 Vpp, offset 0.
-> FUNC:SQU:DCYC 30
-> OUTP ON
//Changes the duty cycle to
30%.
//Turns on output.
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2
Features and Functions
Example 4, To output a Ramp wave
-> *CLS; *RST
//To reset the U2761A to default
power-on state, this command
can be ignored if this operation
is not required.
-> FUNC RAMP
-> VOLT 5 VPP
//Sets the output to Ramp wave.
//Sets the output amplitude to
5 Vpp.
-> FREQ 10000
-> VOLT:OFFS 0
//Sets the output frequency to
10 kHz.
//Sets the output offset to 0.
-> FUNC:RAMP:SYMM 50 //Changes the symmetry to 50%.
-> OUTP ON //Turns on output.
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Pulse Waveform
As shown below, a Pulse waveform consists of a period, a
pulse width, a rising edge, and a falling edge.
90%
90%
50%
50%
Pulse width
Period
10%
Rise time
10%
Fall time
Figure 2-12 Pulse waveform
Pulse Period
The range of the pulse period is from 200 ns to 2000 s. The
width as necessary to accommodate the specified period.
Soft Front Panel Operation
After selecting Pulse
Figure 2-2, on the Frequency panel as shown in Figure 2-3,
select Period , input the desired pulse period value,
at the top panel as shown in
and then select the unit from the drop down list.
Remote Interface Operation
PULSe:PERiod <seconds>
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2
Features and Functions
Pulse Width
The pulse width represents the time from the 50% threshold
of the pulse’s rising edge to the 50% threshold of the next
falling edge.
• The range of the pulse width is 40 ns to <2000 s (see
restrictions below). The default pulse width is 500 μs.
• The minimum pulse width (Wmin) is affected by the
period.
Wmin = 40 ns for period ≤ 10 s
Wmin = 200 ns for period > 10 s, but ≤ 100 s
Wmin = 2 μs for period > 100 s, but ≤ 1000 s
Wmin = 20 μs for period > 1000 s
• The specified pulse width must also be less than the
difference between the period and the minimum pulse
width as shown in the equation below. The U2761A will
adjusts the pulse width as necessary to accommodate the
specified period.
Pulse Width ≤ Period – Wmin
Soft Front Panel Operation
After selecting Pulse
at the top panel as shown in
Figure 2-2, on the Width panel below, input the desired
pulse width value and select the unit from the drop down
list.
Figure 2-13 Panel view of the pulse width section
Remote Interface Operation
FUNCtion:PULSe:WIDTh <seconds>
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Pulse Duty Cycle
The pulse duty cycle is defined as:
Duty Cycle = 100 × Pulse Width / Period
where the pulse width represents the time from the 50%
threshold of the rising edge of the pulse to the 50%
threshold of the next falling edge.
• Pulse duty cycle: >0% to <100% (see restrictions below).
The default is 50%.
• The specified pulse duty cycle must conform to the
following restrictions determined by the minimum pulse
width (Wmin). The U2761A will adjust the pulse duty
cycle as needed to accommodate the specified period.
Duty Cycle ≥ 100 × Wmin / Period
and
Duty Cycle ≤ 100 × (1 – Wmin / Period)
where:
Wmin = 40 ns for period ≤ 10 s.
Wmin = 200 ns for period > 10 s, but ≤ 100 s.
Soft Front Panel Operation
After selecting Pulse
Figure 2-2, select Duty Cycle
at the top panel as shown in
as shown in
Figure 2-13 and input the desired pulse duty cycle value on
the Duty Cycle panel.
Remote Interface Operation
FUNCtion:PULSe:DCYCle <percent>
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2
Features and Functions
Generate Pulse Waveform Using SCPI Commands
Example 1
-> *CLS; *RST
//To reset the U2761A to default
power-on state, this command
can be ignored if this operation
is not required.
-> FUNC PULS
-> VOLT 5 VPP
//Sets the output to Pulse wave.
//Sets the output amplitude to
5 Vpp.
-> VOLT:OFFS 0
-> PULS:PER 1
//Sets the output offset to 0.
//Sets the pulse period to 1 s.
-> FUNC:PULS:DCYC 50 //Set the pulse duty cycle to 50%.
-> OUTP ON //Turns on output.
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Amplitude Modulation (AM)
A modulated waveform consists of a carrier waveform and a
modulating waveform. An example of the AM waveform is
shown in Figure 2-14. In AM, the amplitude of the carrier is
varied by the instantaneous voltage of the modulating
waveform. The amount of amplitude modulation is called the
modulation depth which refers to the portion of the
amplitude range that will be used by the modulation.
Modulating frequency
AM depth
Figure 2-14 AM waveform
To Select AM
The U2761A allows only one modulation mode at a time. The
U2761A does not allow modulation when sweep is enabled.
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2
Features and Functions
Soft Front Panel Operation
Click Mod
and then select AM
as shown in
Figure 2-15. To output the AM waveform, configure the
settings for the carrier frequency, modulating frequency,
depth, output amplitude, offset voltage, and the desired
waveform.
Figure 2-15 Panel view of AM
Remote Interface Operation
AM:STATe {0|OFF|1|ON}
Carrier Waveform
The AM carrier waveform consists of Sine, Square, Ramp,
Triangle, or Arbitrary waveform. The default waveform is
waveform.
Soft Front Panel Operation
For Arbitrary waveform, select Arb
at the top panel
as shown in Figure 2-2 and then select the desired
waveform from the drop down list
Figure 2-16.
as shown in
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Figure 2-16 Panel view of the Arbitrary waveform
Remote Interface Operation
FUNCtion {SINusoid|SQUare|RAMP|USER}
You can also use the APPLy command to select the function,
frequency, amplitude, and offset.
Carrier Frequency
The maximum carrier frequency depends on the selected
function as shown below. The default frequency is 1 kHz for
all functions.
Table 2-3 Carrier frequency for AM
Function
Sine
Minimum frequency
Maximum frequency
20 MHz
1 μHz
1 μHz
1 μHz
1 μHz
Square
20 MHz
Ramp, Triangle
Arbitrary
200 kHz
200 kHz
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2
Features and Functions
Soft Front Panel Operation
On the Frequency panel as shown in Figure 2-3, input the
desired frequency value and select the unit from the drop
down list.
Remote Interface Operation
FREQuency <frequency>
You can also use the APPLy command to select the function,
frequency, amplitude, and offset.
Modulating Waveform
The modulating waveform consists of Sine, Square, Ramp,
Negative Ramp (Nramp), Triangle, or Arbitrary waveform.
The default modulating waveform is Sine wave.
• Square has 50% duty cycle
• Ramp has 100% symmetry
• Triangle has 50% symmetry
• Negative Ramp has 0% symmetry
Soft Front Panel Operation
Select the desired modulating waveform from the drop down
list
as shown in Figure 2-15.
Remote Interface Operation
AM:INTernal:FUNCtion
{SINusoid|SQUare|RAMP|NRAMp|TRIangle|USER}
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Modulating Waveform Frequency
The range of the modulating waveform frequency is 2 mHz
to 20 kHz. The default modulating waveform frequency is
100 Hz.
Soft Front Panel Operation
On the Mod Frequency panel as shown in Figure 2-15, input
the desired modulating frequency value and select the unit
from the drop down list.
Remote Interface Operation
AM:INTernal:FREQuency <frequency>
Modulation Depth
The modulation depth is expressed in percentage and
represents the extent of the amplitude variation. At 0%
depth, the output amplitude is half of the selected value. At
100% depth, the output amplitude equals the selected value.
The range of the modulation depth is 0% to 100%. The
default modulation depth is 100%.
peak (into a 50 Ω load).
NOTE
Soft Front Panel Operation
On the Depth panel as shown in Figure 2-15, select the
desired modulating depth value from the drop down list.
Remote Interface Operation
AM:DEPTh <depth in percent>
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2
Features and Functions
Generate AM Using SCPI Commands
Example 1
-> *CLS; *RST
//To reset the U2761A to default
power-on state, this command
can be ignored if this operation
is not required.
-> AM:STAT ON
-> FUNC SQU
//Enables AM.
//Sets the carrier waveform to
Square wave.
-> FREQ 2000
-> VOLT 5 VPP
//Sets the carrier frequency to
2 kHz.
//Sets the output amplitude to
5 Vpp.
-> VOLT:OFFS 0
//Sets the output offset to 0.
-> AM:INT:FUNC SIN
//Changes the modulating
waveform shape to Sine wave.
-> AM:INT:FREQ 500
-> AM:DEPT 50
-> OUTP ON
//Changes the modulating
frequency to 500 Hz.
//Changes the modulation depth
to 50%.
//Turns on output.
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Features and Functions
2
Frequency Modulation (FM)
A modulated waveform consists of a carrier waveform and a
modulating waveform. Below shows an example of the FM
waveform. In FM, the frequency of the carrier is varied by
the instantaneous voltage of the modulating waveform. The
variation in frequency of the modulated waveform from the
carrier frequency is called the frequency deviation.
Modulating frequency
FM deviation
Figure 2-17 FM waveform
To Select FM
The U2761A allows only one modulation mode to be enabled
at a time. The U2761A does not allow FM to be enabled at
the same time that sweep is enabled.
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2
Features and Functions
Soft Front Panel Operation
Click Mod
and then select FM
as shown in
Figure 2-18. To output the FM waveform, configure the
settings for the carrier frequency, output amplitude, offset
voltage, modulating frequency, deviation, and the desired
waveform.
Figure 2-18 Panel view of FM
Remote Interface Operation
FM:STATe {0|OFF|1|ON}
Carrier Waveform
The FM carrier waveform consists of Sine, Square, Ramp,
Triangle, or Arbitrary waveform. The default waveform is
waveform.
Soft Front Panel Operation
For Arbitrary waveforms, select Arb
at the top panel
as shown in Figure 2-2 and select the desired waveform
from the drop down list
Figure 2-16.
as shown in
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Remote Interface Operation
FUNCtion {SINusoid|SQUare|RAMP|USER}
You can also use the APPLy command to select the function,
frequency, amplitude, and offset.
Carrier Frequency
The maximum carrier frequency depends on the selected
function as shown below. The default is 1 kHz for all
functions.
Table 2-4 Carrier frequency for FM
Function
Sine
Minimum frequency
Maximum frequency
20 MHz
1 μHz
1 μHz
1 μHz
1 μHz
Square
20 MHz
Ramp, Triangle
Arbitrary
200 kHz
200 kHz
The carrier frequency must always be greater than or equal
to the frequency deviation plus 1 μHz. If you attempt to set
the deviation to a value plus 1 μHz greater than the carrier
frequency (with FM enabled), the U2761A will automatically
adjusts the deviation to the maximum value allowed with the
present carrier frequency.
The sum of the carrier frequency and deviation must be less
than or equal to the maximum frequency for the selected
function (20 MHz for Sine and Square, 200 kHz for Ramp
and Arbitrary waveforms). If you attempt to set the
deviation to a value that is not valid, the U2761A will
automatically adjusts it to the maximum value allowed with
the present carrier frequency.
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Features and Functions
Soft Front Panel Operation
On the Frequency panel as shown in Figure 2-3, input the
desired frequency value and select the unit from the drop
down list.
Remote Interface Operation
FREQuency <frequency>
You can also use the APPLy command to select the function,
frequency, amplitude, and offset.
Modulating Waveform
The modulating waveform consists of Sine, Square, Ramp,
Negative Ramp (Nramp), Triangle, Noise, or Arbitrary
waveform. The default modulating waveform is Sine wave.
• Square has 50% duty cycle
• Ramp has 100% symmetry
• Triangle has 50% symmetry
• Negative Ramp has 0% symmetry
Soft Front Panel Operation
Select the desired modulating waveform from the drop down
list
as shown in Figure 2-18.
Remote Interface Operation
FM:INTernal:FUNCtion
{SINusoid|SQUare|RAMP|NRAMp|TRIangle|USER}
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Modulating Waveform Frequency
The range of the modulating waveform frequency is 2 mHz
to 20 kHz. The default modulating waveform frequency is
100 Hz.
Soft Front Panel Operation
On the Mod Frequency panel as shown in Figure 2-18, input
the desired modulating frequency value and select the unit
from the drop down list.
Remote Interface Operation
FM:INTernal:FREQuency <frequency>
Frequency Deviation
The frequency deviation setting represents the peak variation
in frequency of the modulated waveform from the carrier
frequency.
The range of the frequency deviation is 1 Hz to 500 kHz
(limited to 100 kHz minus 1 μHz for Ramp and Arbitrary
waveforms). The default frequency deviation is 100 Hz.
The carrier frequency must always be greater than or equal
to the frequency deviation plus 1 μHz. If you attempt to set
the deviation to a value plus 1 μHz greater than the carrier
frequency (with FM enabled), the U2761A will automatically
adjusts the deviation to the maximum value allowed with the
present carrier frequency.
The sum of the carrier frequency and deviation must be less
than or equal to the maximum frequency for the selected
function (20 MHz for Sine and Square, and 200 kHz for
Ramp and Arbitrary waveforms). If you attempt to set the
deviation to a value that is not valid, the U2761A will
automatically adjusts it to the maximum value allowed with
the present carrier frequency.
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Features and Functions
Soft Front Panel Operation
On the Deviation panel as shown in Figure 2-18, input the
desired frequency deviation value and select the unit from
the drop down list.
Remote Interface Operation
FM:DEViation <peak deviation in Hz>
Generate FM Using SCPI Commands
Example 1
-> *CLS; *RST
//To reset the U2761A to default
power-on state, this command
can be ignored if this operation
is not required.
-> FM:STAT ON
-> FUNC SIN
//Enables FM.
//Sets the carrier waveform to
Sine wave.
-> FREQ 1000
-> VOLT 5 VPP
//Sets the carrier frequency to
1 kHz.
//Sets the output amplitude to
5 Vpp.
-> VOLT:OFFS 0
//Sets the output offset to 0.
-> FM:INT:FUNC SIN
//Changes the modulating
waveform shape to Sine wave.
-> FM:INT:FREQ 500
-> FM:DEV 100
-> OUTP ON
//Changes the modulating
frequency to 500 Hz.
//Changes the frequency
deviation to 100 Hz.
//Turns on output.
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Phase Modulation (PM)
A modulated waveform consists of a carrier waveform and a
modulating waveform. The following figure shows an example
of a PM waveform. PM is very similar to FM, but in PM, the
phase of the modulated waveform is varied by the
instantaneous voltage of the modulating waveform. The
variation in phase of the modulated waveform from the
carrier waveform is called the phase deviation.
Modulating frequency
Phase deviation
Figure 2-19 PM waveform
To Select PM
The U2761A allows only one modulation mode to be enabled
at a time. The U2761A does not allow PM to be enabled at
the same time that sweep is enabled.
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Features and Functions
Soft Front Panel Operation
Click Mod
and then select PM
as shown in
Figure 2-20. To output the PM waveform, configure the
settings for the carrier frequency, output amplitude, offset
voltage, modulating frequency, phase deviation, and the
desired waveform.
Figure 2-20 Panel view of PM
Remote Interface Operation
PM:STATe {0|OFF|1|ON}
Carrier Waveform
The PM carrier waveform consists of Sine, Square, Ramp,
Triangle, or Arbitrary waveform. The default waveform is
waveform.
Soft Front Panel Operation
For Arbitrary waveforms, click Arb
at the top panel
as shown in Figure 2-2 and select the desired waveform
from the drop down list
as shown in Figure 2-16.
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Remote Interface Operation
FUNCtion {SINusoid|SQUare|RAMP|USER}
You can also use the APPLy command to select the function,
frequency, amplitude, and offset.
Carrier Frequency
The maximum carrier frequency depends on the function
selected as shown below. The default carrier frequency is
1 kHz for all functions.
Table 2-5 Carrier frequency for PM
Function
Sine
Minimum frequency
Maximum frequency
20 MHz
1 μHz
1 μHz
1 μHz
1 μHz
Square
20 MHz
Ramp, Triangle
Arbitrary
200 kHz
Soft Front Panel Operation
On the Frequency panel as shown in Figure 2-3, input the
desired frequency value and select the unit from the drop
down list.
Remote Interface Operation
FREQuency <frequency>
You can also use the APPLy command to select the function,
frequency, amplitude, and offset.
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Features and Functions
Modulating Waveform
The modulating waveform consists of Sine, Square, Ramp,
Negative Ramp (Nramp), Triangle, or Arbitrary waveform.
The default waveform is Sine wave.
• Square has 50% duty cycle
• Ramp has 100% symmetry
• Triangle has 50% symmetry
• Negative Ramp has 0% symmetry
Soft Front Panel Operation
Select the desired modulating waveform from the drop down
list
as shown in Figure 2-20.
Remote Interface Operation
PM:INTernal:FUNCtion
{SINusoid|SQUare|RAMP|NRAMp|TRIangle|USER}
Modulating Waveform Frequency
The range of the modulating waveform frequency is 2 mHz
to 20 kHz. The default modulating waveform frequency is
10 Hz.
Soft Front Panel Operation
On the Mod Frequency panel as shown in Figure 2-20, input
the desired modulating frequency value and select the unit
from the drop down list.
Remote Interface Operation
PM:INTernal:FREQuency <frequency>
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Phase Deviation
The phase deviation setting represents the peak variation in
phase of the modulated waveform from the carrier
waveform. The phase deviation setting can be set from
0 to 360°. The default phase deviation setting is 180°.
Soft Front Panel Operation
On the Phase Deviation panel as shown in Figure 2-20,
input the desired phase deviation value.
Remote Interface Operation
PM:DEViation <deviation in degrees>
Generate PM Using SCPI Commands
Example 1
-> *CLS; *RST
//To reset the U2761A to default
power-on state, this command
can be ignored if this operation
is not required.
-> PM:STAT ON
-> FUNC SIN
//Enables PM.
//Sets the carrier waveform to
Sine wave.
-> FREQ 1000
-> VOLT 5 VPP
//Sets the carrier frequency to
1 kHz.
//Sets the output amplitude to
5 Vpp.
-> VOLT:OFFS 0
-> PM:INT:FUNC SIN
//Sets the output offset to 0.
//Changes the modulating
waveform shape to Sine wave.
//Changes the modulating
frequency to 500 Hz.
//Changes the phase deviation to
180°.
-> PM:INT:FREQ 500
-> PM:DEV 180
-> OUTP ON
//Turns on output.
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Features and Functions
Frequency-Shift Keying (FSK) Modulation
FSK is similar to FM except that the frequency alternates
between two preset values. You can configure the U2761A to
“shift” its output frequency between two preset values using
FSK modulation. An example of the FSK modulation
waveform is shown below. The rate at which the output
shifts between the two frequencies (called the “carrier
frequency” and the “hop frequency”) is determined by the
internal rate generator.
FSK rate
Hop frequency
Figure 2-21 FSK modulation waveform
To Select FSK Modulation
The U2761A allows only one modulation mode to be enabled
at a time. The U2761A does not allow FSK to be enabled at
the same time that sweep is enabled.
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Soft Front Panel Operation
Click Mod
and select FSK
as shown in
Figure 2-22. To output the FSK waveform, configure the
settings for the carrier frequency, output amplitude, offset
voltage, “hop frequency”, and FSK rate.
Figure 2-22 Panel view of FSK
Remote Interface Operation
FSKey:STATe {0|OFF|1|ON}
Carrier Waveform
The FSK carrier waveform consists of Sine, Square, Ramp,
Triangle, or Arbitrary waveform. The default carrier
carrier waveform.
Soft Front Panel Operation
For Arbitrary waveforms, click Arb
at the top panel
as shown in Figure 2-2 and select the desired waveform
from the drop down list
Figure 2-16.
as shown in
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Features and Functions
Remote Interface Operation
FUNCtion {SINusoid|SQUare|RAMP|USER}
You can also use the APPLy command to select the function,
frequency, amplitude, and offset.
FSK Carrier Frequency
The maximum carrier frequency depends on the function
selected as shown below. The default carrier frequency is
1 kHz for all functions.
Table 2-6 Carrier frequency for FSK
Function
Sine
Minimum frequency
Maximum frequency
20 MHz
1 μHz
1 μHz
1 μHz
1 μHz
Square
20 MHz
Ramp, Triangle
Arbitrary
200 kHz
Soft Front Panel Operation
On the Frequency panel as shown in Figure 2-3, input the
desired frequency value and select the unit from the drop
down list.
Remote Interface Operation
FREQuency <frequency>
You can also use the APPLy command to select the function,
frequency, amplitude, and offset.
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FSK “Hop” Frequency
The maximum alternate (or “hop”) frequency depends on the
function selected as shown below. The default “hop”
frequency is 100 Hz for all functions.
Table 2-7 “Hop” frequency
Function
Sine
Minimum frequency
Maximum frequency
20 MHz
1 μHz
1 μHz
1 μHz
1 μHz
Square
20 MHz
Ramp, Triangle
Arbitrary
200 kHz
200 kHz
Only Square wave with a 50% duty cycle is available for the
Internal FSK modulating waveform.
Soft Front Panel Operation
On the Hop Frequency panel as shown in Figure 2-22, input
the desired hop frequency value and select the unit from the
drop down list.
Remote Interface Operation
FSKey:FREQuency <frequency>
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Features and Functions
FSK Rate
The FSK rate is the rate at which the output frequency
“shifts” between the carrier frequency and the hop
frequency.
• The range of the FSK rate is 2 mHz to 100 kHz. The
default FSK rate value is 10 Hz.
Soft Front Panel Operation
On the FSK Rate panel as shown in Figure 2-22, input the
desired FSK rate value and select the unit from the drop
down list.
Remote Interface Operation
FSKey:INTernal:RATE <rate in Hz>
Generate FSK Modulation Using SCPI Commands
Example 1
-> *CLS; *RST
//To reset the U2761A to default
power-on state, this command
can be ignored if this operation
is not required.
-> FSK:STAT ON
-> FUNC SIN
//Enables FSK modulation.
//Sets the carrier waveform to
Sine wave.
-> FREQ 1000
-> VOLT 5 VPP
//Sets the carrier frequency to
1 kHz.
//Sets the output amplitude to
5 Vpp.
-> VOLT:OFFS 0
-> FSK:FREQ 100
//Sets the output offset to 0.
//Sets the "hop" frequency to
100 Hz.
-> FSK:INT:RATE 10
-> OUTP ON
//Sets the FSK rate to 10 Hz.
//Turns on output.
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Phase-Shift Keying (PSK) Modulation
Phase-shift keying (PSK) is a form of digital modulation in
which the phase of the carrier signal is discretely varied.
You can configure the U2761A to “shift” its output phase
between two preset phases using PSK. The rate at which the
output shifts between the two phases is determined by the
internal rate generator on the signal level. The following
figure shows an example of the PSK modulation waveform.
PSK rate
PSK deviation
Figure 2-23 PSK modulation waveform
To Select PSK Modulation
The U2761A allows only one modulation mode to be enabled
at a time. The U2761A does not allow PSK to be enabled at
the same time that sweep is enabled.
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Features and Functions
Soft Front Panel Operation
Click Mod
and then select PSK
as shown in
Figure 2-24. To output the PSK waveform, configure the
settings for the carrier frequency, output amplitude, offset
voltage, deviation, and PSK rate.
Figure 2-24 Panel view of PSK
Remote Interface Operation
PSKey:STATe {0|OFF|1|ON}
Carrier Waveform
The PSK carrier waveform consists of Sine, Square, Ramp,
Triangle, or Arbitrary waveform. The default waveform is
waveform.
Soft Front Panel Operation
For Arbitrary waveforms, select Arb
at the top panel
as shown in Figure 2-2 and select the desired waveform
from the drop down list
Figure 2-16.
as shown in
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Remote Interface Operation
FUNCtion {SINusoid|SQUare|RAMP|USER}
You can also use the APPLy command to select the function,
frequency, amplitude, and offset.
PSK Carrier Frequency
The maximum carrier frequency depends on the function
selected as shown below. The default is 1 kHz for all functions.
Table 2-8 Carrier frequency for PSK
Function
Sine
Minimum frequency
Maximum frequency
20 MHz
1 μHz
1 μHz
1 μHz
1 μHz
Square
20 MHz
Ramp, Triangle
Arbitrary
200 kHz
200 kHz
Only Square wave with a 50% duty cycle is available for the
Internal PSK modulating waveform.
Soft Front Panel Operation
On the Frequency panel shown in Figure 2-3, input the
desired frequency value and select the unit from the drop
down list.
Remote Interface Operation
FREQuency <frequency>
You can also use the APPLy command to select the function,
frequency, amplitude, and offset.
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Features and Functions
PSK Rate
between two preset phases. The range of the PSK rate is 2
mHz to 100 kHz. The default PSK rate value is 10 Hz.
Soft Front Panel Operation
On the PSK Rate panel as shown in Figure 2-24, input the
desired PSK rate value and select the unit from the drop
down list.
Remote Interface Operation
PSKey:INTernal:RATE <rate in Hz>
PSK Deviation
The deviation setting represents the phase variation of the
shifted waveform from the carrier waveform. The deviation
can be set from 0 to 360°. The default deviation setting is
180°.
Soft Front Panel Operation
On the Deviation panel as shown in Figure 2-24, input the
desired deviation value.
Remote Interface Operation
PSKey:DEViation <deviation in degrees>
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Generate PSK Modulation Using SCPI Commands
Example 1
-> *CLS; *RST
//To reset the U2761A to
default power-on state, this
command can be ignored if
this operation is not
required.
-> PSK:STAT ON
-> FUNC SIN
//Enables PSK modulation.
//Sets the carrier waveform to
Sine wave.
-> FREQ 1000
-> VOLT 5 VPP
//Sets the carrier frequency to
1 kHz.
//Sets the output amplitude to
5 Vpp.
-> VOLT:OFFS 0
//Sets the output offset to 0.
-> PSK:INT:RATE 10
//Sets the PSK rate to
10 Hz.
-> PSK:DEV 180
-> OUTP ON
//Sets the PSK deviation to
180°.
//Turns on output.
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Features and Functions
Amplitude-Shift Keying (ASK) Modulation
ASK is a form of digital modulation in which the modulating
signal apply variations in the amplitude of a carrier signal.
The amplitude of the carrier signal varies simultaneously
with the modulating signal while phase and frequency
remain constant. In other words, the carrier signal can be
assumed as an on and off switch. You can configure the
U2761A to “shift” its output amplitude between two preset
amplitudes using ASK. The rate at which the output shifts
between the two amplitudes is determined by the internal
rate generator. An example of the ASK modulation waveform
is shown in the following.
ASK rate
Figure 2-25 ASK modulation waveform
To Select ASK Modulation
The U2761A allows only one modulation mode to be enabled
at a time. The U2761A does not allow ASK to be enabled at
the same time that sweep is enabled.
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Soft Front Panel Operation
Click Mod
and then select ASK
as shown in
Figure 2-26. To output the ASK waveform, configure the
settings for the carrier frequency, output amplitude, offset
voltage, and ASK rate.
Figure 2-26 Panel view of ASK
Remote Interface Operation
ASKey:STATe {0|OFF|1|ON}
Carrier Waveform
The ASK carrier waveform consists of Sine, Square, Ramp,
Triangle, or Arbitrary waveform. The default waveform is
waveform.
Soft Front Panel Operation
For Arbitrary waveforms, select Arb
at the top panel
as shown in Figure 2-2 and select the desired waveform
from the drop down list
Figure 2-16.
as shown in
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Features and Functions
Remote Interface Operation
FUNCtion {SINusoid|SQUare|RAMP|USER}
You can also use the APPLy command to select the function,
frequency, amplitude, and offset.
Carrier Frequency
The maximum carrier frequency depends on the function
selected as shown below. The default is 1 kHz for all functions.
Table 2-9 Carrier frequency for ASK
Function
Sine
Minimum frequency
Maximum frequency
20 MHz
1 μHz
1 μHz
1 μHz
1 μHz
Square
20 MHz
Ramp, Triangle
Arbitrary
200 kHz
200 kHz
Only Square wave with a 50% duty cycle is available for the
Internal ASK modulating waveform.
Soft Front Panel Operation
On the Frequency panel as shown in Figure 2-3, input the
desired frequency value and select the unit from the drop
down list.
Remote Interface Operation
FREQuency <frequency>
You can also use the APPLy command to select the function,
frequency, amplitude, and offset.
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ASK Rate
The ASK rate is the rate at which the output amplitude
“shifts” between two preset amplitudes. The range of the
ASK rate is 2 mHz to 100 kHz. The default ASK rate value is
10 Hz.
Soft Front Panel Operation
On the ASK Rate panel as shown in Figure 2-26, input the
desired ASK rate value and select the unit from the drop
down list.
Remote Interface Operation
ASKey:INTernal:RATE <rate in Hz>
Generate ASK Modulation Using SCPI Commands
Example 1
-> *CLS; *RST
//To reset the U2761A to
default power-on state, this
command can be ignored if
this operation is not
required.
-> ASK:STAT ON
-> FUNC SIN
//Enables ASK modulation.
//Sets the carrier waveform to
Sine wave.
-> FREQ 1000
-> VOLT 5 VPP
//Sets the carrier frequency to
1 kHz.
//Sets the output amplitude to
5 Vpp.
-> VOLT:OFFS 0
//Sets the output offset to 0.
-> ASK:INT:RATE 10
//Sets the ASK rate to
10 Hz.
-> OUTP ON
//Turns on output.
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Features and Functions
Frequency Sweep
In the frequency sweep mode, the U2761A “steps” from the
start frequency to the stop frequency at a sweep rate which
you specify. You can sweep up or down in frequency, and
with either linear or logarithmic spacing. You can also
configure the U2761A to output a single sweep (one pass
from start frequency to stop frequency) by applying an
External or Manual (software) trigger. The U2761A can
produce a frequency sweep for Sine, Square, Ramp, Triangle,
or Arbitrary’s waveform (Pulse and DC are not allowed). The
figure below shows an example of the frequency sweep.
Frequency
Linear type
Start frequency
Stop frequency
Figure 2-27 Frequency sweep
To Select Sweep
The U2761A does not allow the sweep mode to be enabled at
the same time that any modulation mode is enabled.
Soft Front Panel Operation
Click Sweep
as shown in Figure 2-28. To output
sweep, configure the settings for frequencies, output
amplitude, offset, sweep type and time, and trigger setup.
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Figure 2-28 Panel view of sweep
Remote Interface Operation
SWEep:STATe {0|OFF|1|ON}
Start Frequency and Stop Frequency
The start frequency and stop frequency sets the upper and
lower frequency bounds for the sweep. The U2761A begins at
the start frequency, sweeps to the stop frequency, and then
resets back to the start frequency.
• The range of the start and stop frequencies is 1 μHz to
20 MHz (limited to 200 kHz for Ramp and Arbitrary
waveforms). The sweep is phase-continuous over the full
frequency range. The default start frequency is 100 Hz. The
default stop frequency is 1 kHz.
• To sweep up in frequency, set the start frequency < stop
frequency > stop frequency.
Soft Front Panel Operation
On the Start Frequency and Stop Frequency panels as
shown in Figure 2-28, input the desired start frequency and
stop frequency values and select the respective units from
the drop down lists.
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Features and Functions
Remote Interface Operation
FREQuency:STARt <frequency>
FREQuency:STOP <frequency>
Sweep Mode
You can sweep with either linear or logarithmic spacing. For
a linear sweep, the U2761A varies the output frequency in a
linear fashion during the sweep. For a logarithmic sweep,
the U2761A varies the output frequency in a logarithmic
fashion.
The sweep mode consists of Linear or Logarithmic. The
default sweep mode is Linear.
Soft Front Panel Operation
On the Sweep Type panel as shown in Figure 2-28, select
the Linear
or Log
mode.
Remote Interface Operation
SWEep:SPACing {LINear|LOGarithmic}
Sweep Time
The sweep time specifies the number of seconds required to
sweep from the start frequency to the stop frequency. The
number of discrete frequency points in the sweep is
automatically calculated by the U2761A and is based on the
sweep time you have selected. The range of the sweep time
is 1 ms to 500 s. The default sweep time is 1 s.
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Soft Front Panel Operation
On the Sweep Time panel as shown in Figure 2-28, input
the desired sweep time and select the unit from the drop
down list.
Remote Interface Operation
SWEep:TIME <seconds>
Sweep Trigger Source
In the sweep mode, the U2761A outputs a single sweep
when a trigger signal is received. After one sweep from the
start frequency to the stop frequency, the U2761A will
continuously output the preset waveform at the start
frequency while waiting for the next trigger.
• The sweep trigger source consists of Internal (immediate),
External, or Manual (software). The default trigger source
is Internal.
• When the Internal source is selected, the U2761A outputs
a continuous sweep at a rate determined by the specified
sweep time.
• When the External source is selected, the U2761A accepts
a hardware trigger applied to the device Trig In
connector. The U2761A initiates one sweep each time
Trig In receives a TTL pulse with the specified polarity.
one sweep each time the soft front panel Trigger
is
clicked.
Soft Front Panel Operation
On the Trigger Setup panel as shown in Figure 2-28, select
the desired sweep trigger source from the drop down list
at the Source panel.
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Features and Functions
To specify whether the U2761A is triggered on the rising or
falling edge of the signal from the Trig In connector, select
Positive
for rising edge triggering and Negative
for falling edge triggering.
Remote Interface Operation
TRIGger:SOURce {IMMediate|EXTernal|BUS}
Use the following command to specify whether the U2761A
is triggered on the rising or falling edge of the signal from
the Trig In connector.
TRIGger:SLOPe {POSitive|NEGative}
Set Frequency Sweep Using SCPI Commands
Example 1
-> *CLS; *RST
//To reset the U2761A to default
power-on state, this command
can be ignored if this operation
is not required.
-> FUNC SIN
//Sets the carrier waveform to
Sine wave.
-> VOLT 5 VPP
//Sets the output amplitude to
5 Vpp.
-> VOLT:OFFS 0
-> SWE:STAT ON
-> FREQ:STAR 500
//Sets the output offset to 0.
//Enables frequency sweep.
//Changes the start frequency to
500 Hz.
-> FREQ:STOP 10000
-> SWE:SPAC LIN
//Changes the stop frequency to
10 kHz.
//Changes the sweep mode to
Linear.
-> SWE:TIME 2
//Changes the sweep time to 2 s.
-> TRIG:SOUR EXT
//Changes the sweep trigger
source to External.
-> TRIG:SLOP POS
-> OUTP ON
//Changes the U2761A to be
triggered on the rising edge.
//Turns on output.
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Triggering
Applies to sweep only. You can issue triggers for sweeps
using Internal (immediate) triggering, External triggering, or
Manual (software) triggering.
• Internal triggering is enabled when you turn on the
U2761A. In this mode, the U2761A outputs continuously
when the sweep mode is selected.
• External triggering uses the device Trig In connector to
control the sweep. The U2761A initiates one sweep each
time Trig In receives a TTL pulse. You can select whether
the U2761A is triggered on the rising or falling edge of
the External trigger signal.
• Manual triggering initiates one sweep each time you click
Trigger
on the soft front panel.
Trigger Source Choices
You must specify the source from which the U2761A accepts
a trigger.
• The sweep trigger source consists of Internal, External, or
Manual. The default trigger source is Internal.
• The U2761A accepts a Manual trigger, a hardware trigger
from the device Trig In connector, or continuously output
sweeps using an Internal trigger. At power-on, Internal
trigger is selected.
where the source is set to Internal (immediate) trigger
upon power-off or after a remote interface reset.
Soft Front Panel Operation
On the Trigger Setup panel as shown in Figure 2-28, select
the desired trigger source from the drop down list
at the Source panel.
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Features and Functions
Remote Interface Operation
TRIGger:SOURce {IMMediate|EXTernal|BUS}
Internal Triggering
In the Internal trigger mode, the U2761A continuously
performs frequency sweep (as specified by the sweep time).
This is the default trigger source for both soft front panel
and remote interface use.
Soft Front Panel Operation
On the Trigger Setup panel as shown in Figure 2-28, select
Internal from the drop down list
at the Source
panel.
Remote Interface Operation
TRIGger:SOURce IMMediate
Manual Triggering
In the Manual (software) triggering mode, you can manually
trigger the U2761A by clicking Trigger . The U2761A
initiates one sweep each time you click the button. The
Trigger button is illuminated while the U2761A waits
for a Manual trigger.
Soft Front Panel Operation
On the Trigger Setup panel as shown in Figure 2-28, select
Manual from the drop down list
at the Source
panel.
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Remote Interface Operation
TRIGger:SOURce BUS
When the BUS source is selected, send the TRIG or *TRG
command to trigger the U2761A.
External Triggering
In the External trigger mode, the U2761A accepts a
hardware trigger applied to the device Trig In connector. The
U2761A initiates one sweep each time Trig In receives a TTL
pulse with the specified edge.
Also refer to “Trigger Input Signal” on page 88.
Soft Front Panel Operation
On the Trigger Setup panel as shown in Figure 2-28, select
External from the drop down list
at the Source
panel.
To specify whether the U2761A is triggered on the rising or
falling edge, select Positive
rising edge and Negative
edge.
for triggering on the
for triggering on the falling
Remote Interface Operation
TRIGger:SOURce EXTernal
Use the following command to specify whether the U2761A
is triggered on the rising or falling edge.
TRIGger:SLOPe {POSitive|NEGative}
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Features and Functions
Trigger Input Signal
Trigger in
Rising edge shown
The device connector is used for Triggered Sweep Mode,
refer to “Sweep Trigger Source” on page 83. When the rising
or falling edge of the TTL pulse is received on the Trig In
connector, the U2761A outputs a single sweep, refer to
“External Triggering” on page 87.
Trigger Output Signal
A “trigger out” signal is provided on the device Trig Out
connector (used with sweep only). When enabled, a
TTL-compatible Square waveform with either a rising
(default) or falling edge is output to the device Trig Out
connector at the beginning of the sweep.
Trigger out
> 500 μs
Rising edge shown
Figure 2-30 Trigger output pulse
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When the Internal (immediate) trigger source is selected, the
U2761A outputs a Square waveform with a 50% duty cycle to
the Trig Out connector at the beginning of the sweep. The
period of the Square waveform is equal to the specified
sweep time.
When the Manual (software) trigger source is selected, the
U2761A outputs a pulse to the Trig Out connector at the
beginning of each sweep.
Soft Front Panel Operation
After enabling sweep, to specify whether the U2761A outputs
a TTL-compatible Square waveform with either a rising or
falling edge, select Positive
for rising edge and
Negative
for falling edge.
Remote Interface Operation
OUTPut:TRIGger {0|OFF|1|ON}
OUTPut:TRIGger:SLOPe {POSitive|NEGative}
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Features and Functions
Set Triggering Using SCPI Commands
Example 1
-> *CLS; *RST
//To reset the U2761A to
default power-on state,
this command can be
ignored if this operation
is not required.
-> FUNC SIN
//Sets the carrier waveform
to Sine wave.
-> VOLT 5 VPP
-> VOLT:OFFS 0
//Sets the output amplitude
to 5 Vpp.
//Sets the output offset to
0.
-> SWE:STAT ON
//Enables frequency sweep.
-> FREQ:STAR 500
//Changes the start
frequency to 500 Hz.
-> FREQ:STOP 10000
-> SWE:SPAC LIN
-> SWE:TIME 2
//Changes the stop
frequency to 10 kHz.
//Changes the sweep mode
to Linear.
//Changes the sweep time
to 2 s.
-> TRIG:SOUR IMM
-> OUTP:TRIG ON
-> OUTP:TRIG:SLOP POS
-> OUTP ON
//Changes the sweep trigger
source to Internal.
//Turns on the trigger
output.
//Outputs the trigger on a
rising edge.
//Turns on output.
90
U2761A User’s Guide
Features and Functions
2
Arbitrary Waveforms
There are three built-in Arbitrary waveforms offered. The
U2761A supports the Arbitrary waveform up to 65536 (64K)
data points. You can create an Arbitrary waveform using the
soft front panel as described in the following. For further
information, please refer to the Agilent Measurement
Manager help file.
To Create and Store an Arbitrary Waveform
This section provides you an example on the procedure to
create and store an Arbitrary waveform using the soft front
panel. To create an Arbitrary waveform remotely, refer to
the Agilent U2761A USB Modular Function/Waveform
Generator Programmer’s Reference. You will create and store
the Ramp waveform shown below as an example.
Amplitude = 2 Vpp, Period = 10 ms
Figure 2-31 Ramp waveform
U2761A User’s Guide
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2
Features and Functions
1 Select the Arbitrary waveform function.
Click Arb to select the Arbitrary function.
2 Set the waveform period.
Select Period
numeric drop down
waveform.
and use the numeric keypad or
to set the period for the
For example, set the period of the waveform to 10 ms.
3 Set the waveform voltage limits.
Select HiLevel
and Lolevel
to set the
high and low voltage levels that can be reached while
editing the waveform. The upper limit must be greater
than the lower limit.
For example, set the upper limit to 2.0 V and the lower
limit to 0 V.
4 Start the Arbitrary waveform editor.
Select Non Built-in Waveform from the Arbitrary’s drop down
list
and click
to start the Arbitrary
waveform editor.
5 Select the interpolation method.
Click to enable or disable linear interpolation between
the user-defined points. With interpolation enabled
(default), the waveform editor makes a straight-line
connection between the points. With interpolation
disabled, the waveform editor maintains a constant
voltage level between the points and creates a “step-like’
waveform.
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U2761A User’s Guide
Features and Functions
2
6 Start waveform editing process.
Click
to begin the freehand draw mode or
to
enable line draw mode. To enable or disable the grid
reference, click . Then, start drawing the desired
waveform. To edit the waveform, click either to add
line/point(s), to edit point(s), to delete point(s),
or to clear current Arbitrary graph.
7 Sending waveform to the U2761A.
To send the waveform to the U2761A, click
.
Once the Send waveform in progress has completed, the Send
waveform has completed message is displayed.
The downloading of an Arbitrary waveform may take up to several
minutes. The status bar at the bottom of the Arbitrary waveform editor
window shows the progress of the download. Please wait for the Send
waveform has completed message to be displayed before proceeding
with the next step.
NOTE
Figure 2-32 Waveform download in progress
U2761A User’s Guide
93
2
Features and Functions
8 Saving the waveform.
To save the waveform for future use, click
. Then,
select Compatible With Intuilink and click
. Input the
desired file name and click
to save the file.
9 Exiting the waveform editor.
To exit the waveform editor, click
.
94
U2761A User’s Guide
Agilent U2761A USB Modular Function/Arbitrary Waveform Generator
User’s Guide
3
Characteristics and Specifications
Product Characteristics 96
Product Specifications and Characteristics 97
This chapter specifies the characteristics, environmental
conditions, and specifications of the U2761A.
Agilent Technologies
95
3
Characteristics and Specifications
Product Characteristics
REMOTE INTERFACE
•
•
Hi-Speed USB 2.0
USBTMC 488.2 Class device
POWER CONSUMPTION
•
•
+12 VDC, 2 A
Isolated ELV power source
OPERATING ENVIRONMENT
•
•
•
•
•
Operating temperature from 0 °C to 50 °C
Operating humidity at 20% to 85% RH (non-condensing)
Altitude up to 2000 meters
Pollution Degree 2
For indoor use only
STORAGE COMPLIANCE
•
•
Storage temperature from –20 °C to 70 °C
Storage humidity at 5% to 90% RH (non-condensing)
SAFETY COMPLIANCE
Certified with:
•
•
•
IEC 61010-1:2001/EN61010-1:2001 (2nd Edition)
Canada: CAN/CSA-C22.2 No. 61010-1-04
USA: ANSI/UL 61010-1:2004
EMC COMPLIANCE
•
•
•
IEC 61326-2002/EN 61326:1997+A1:1998+A2:2001+A3:2003
Canada: ICES-001:2004
Australia/New Zealand: AS/NZS CISPR11:2004
SHOCK & VIBRATION
Tested to IEC/EN 60068-2
IO CONNECTOR
BNC connector
DIMENSION (W×D×H)
•
117.00 mm × 180.00 mm × 41.00 mm (with bumpers)
•
105.00 mm × 175.00 mm × 25.00 mm (without bumpers)
WEIGHT
•
•
528g (with bumpers)
476 g (without bumpers)
WARRANTY
One year
96
U2761A User’s Guide
Characteristics and Specifications
3
Product Specifications and Characteristics
WAVEFORMS
Standard
Sine, Square, Ramp, Triangle, Pulse, DC
Built-in arbitrary
Exponential Rise, Exponential Fall, Negative Ramp
WAVEFORM CHARACTERISTICS
Sine
Frequency range
1 μHz to 20 MHz (1 μHz resolution)
1
Amplitude flatness
<100 kHz
0.2 dB
(relative to 1 kHz)
100 kHz to 1 MHz
1 MHz to 20 MHz
Frequency range
DC to 20 kHz
0.35 dB
0.7 dB
2
Harmonic distortion
<1 Vpp
–70 dBc
–65 dBc
–50 dBc
–40 dBc
0.10%
≥1 Vpp
–60 dBc
–60 dBc
–45 dBc
–35 dBc
20 kHz to 100 kHz
100 kHz to 1 MHz
1 MHz to 20 MHz
DC to 20 kHz
2
Total harmonic distortion
3
Spurious (Non-harmonic) output
DC to 1 MHz
–65 dBc
1 MHz to 20 MHz
–115 dBc/Hz (Typical)
–65 dBc + 6 dB/octave
Phase noise (10 kHz offset)
Square
Frequency range
Rise/fall time
1 μHz to 20 MHz (1 μHz resolution)
<18 ns, 10 to 90% terminated load (50 Ω)
<2%
Overshoot
Variable duty cycle
20% to 80% (up to 10 MHz)
40% to 60% (up to 20 MHz)
Asymmetry (@ 50% duty)
Jitter (RMS)
1% of period + 5 ns
> 50 kHz = 1 ns + 100 ppm of period
≤ 50 kHz = 10 ns + 100 ppm of period
U2761A User’s Guide
97
3
Characteristics and Specifications
Ramp, Triangle
Frequency range
Linearity
1 μHz to 200 kHz (1 μHz resolution)
<0.2% of peak output
0% to 100%
Programmable symmetry
Pulse
Frequency range
Pulse width (period ≤ 10 s)
Overshoot
500 μHz to 5 MHz (1 μHz resolution)
40 ns minimum, 10 ns resolution
<3%
Jitter (RMS)
300 ps + 0.1 ppm of period
Arbitrary
Frequency range
Memory depth
Amplitude resolution
Sampling rate
1 μHz to 200 kHz (1 μHz resolution)
64 kSa
14 bits/sample (including sign)
50 MSa/s
Minimum rise/fall time
Linearity
36 ns, typical
<0.2% of peak output
<250 ns to 0.5% of final value
10 ns + 30 ppm
Settling time
Jitter (RMS)
98
U2761A User’s Guide
Characteristics and Specifications
3
COMMON CHARACTERISTICS
Amplitude
Range
40 mVpp to 5 Vpp (Into 50 Ω load)
80 mVpp to 10 Vpp (Into open circuit)
1% of settling 5 mV (±10 mV @ Hi-Z)
Vpp, Vrms, dBm
1
Accuracy (across 50 Ω load at 1 kHz)
Units
Resolution
4 digits
DC offset
Range (peak AC + DC)
2.5 V (Into 50 Ω load)
5 V (Into open circuit)
1
Accuracy (across 50 Ω load)
2% of offset setting 1% of amplitude setting 5 mV
( 10 mV @ Hi-Z)
Amplitude limit
Amplitude + Offset limit to within 2.5 V range across 50 Ω load or
5 V across open circuit
Main output
Impedance
50 Ω load (Typical)
Isolation
At least 42 Vpk to earth
Protection
Short-circuit protected, overload automatically disables main output
Internal frequency reference
4
Accuracy
8 ppm in 1 year
External frequency reference
Input lock range
Input amplitude level
Impedance
10 MHz 170 Hz
500 mVpp to 5 Vpp
50 Ω AC coupled
<2 s
Lock time
Output frequency
Output amplitude level
Impedance
10 MHz
632 mVpp, typical
Return loss 10 dB typical at 10 MHz
Phase offset
Range
+360° to –360°
0.01°
Resolution
Accuracy
20 ns
U2761A User’s Guide
99
3
Characteristics and Specifications
MODULATION
AM
Carrier waveforms
Source
Sine, Square, Ramp, Arbitrary
Internal
Internal modulation
Depth
Sine, Square, Ramp, Arbitrary (2 mHz to 20 kHz)
0.0% to 100.0%
FM
Carrier waveforms
Source
Sine, Square, Ramp, Arbitrary
Internal
Internal modulation
Deviation
Sine, Square, Ramp, Arbitrary (2 mHz to 20 kHz)
1 Hz to 500 kHz
PM
Carrier waveforms
Source
Sine, Square, Ramp, Arbitrary
Internal
Internal modulation
Deviation
Sine, Square, Ramp, Arbitrary (2 mHz to 20 kHz)
0.0 to 360.0°
FSK
Carrier waveforms
Source
Sine, Square, Ramp, Arbitrary
Internal
Internal modulation
50% duty cycle square (2 mHz to 100 kHz)
PSK
Carrier waveforms
Source
Sine, Square, Ramp, Arbitrary
Internal
Internal modulation
Deviation
50% duty cycle square (2 mHz to 100 kHz)
0.0 to 360.0°
ASK
Carrier waveforms
Source
Sine, Square, Ramp, Arbitrary
Internal
Internal modulation
50% duty cycle square (2 mHz to 100 kHz)
100
U2761A User’s Guide
Characteristics and Specifications
3
SWEEP CHARACTERISTICS
Waveforms
Type
Sine, Square, Ramp, Arbitrary
Linear or Logarithmic
Up or Down
Direction
Sweep time
Trigger
1 ms to 500 s
Single, External, or Internal
TRIGGER CHARACTERISTICS
Trigger input
Input level
TTL compatible
Rising or Falling, Selectable
>100 ns
Slope
Pulse width
Input impedance
Latency
>10 kΩ, DC coupled
<500 ns
Jitter (RMS)
Trigger output
Input level
6 ns (3.5 ns for Pulse)
TTL compatible into ≥1 kΩ
Pulse width
Output impedance
Fanout
>400 ns
50 Ω, typical
4 TTL
Rise time
≤20 ns
th
1 Add 1/10 of output amplitude and offset specification per °C for
operation outside the range of 18 °C to 28 °C.
2 DC offset set to 0 V.
3 Tyical spurious output at low amplitude is –70 dBm.
4 Add 1 ppm/°C (average) for operation outside the range of 18 °C to
28 °C.
U2761A User’s Guide
101
3
Characteristics and Specifications
102
U2761A User’s Guide
Index
Index
A
bus trigger 89
Accuracy 99
firmware 18, 19
Agilent
Connection Expert 19
IO Libraries Suite 14.2 10
91
Sales Office 7, 8
VEE Pro 9
SCPI commands 60
sweep 101
AM 2, 26, 40, 49, 50, 52, 54, 100
Carrier frequency 51
carrier waveform 67, 100
rate 70
trigger 101
Carrier waveform 50, 100
depth 100
compliance
Modulation Depth 53
safety 96
H
storage 96
humidity
52, 57, 58, 63
pin 23
operating 96
storage 96
ASK 2, 26, 76, 79, 100
carrier frequency 78
carrier waveform 77, 100
rate 79
Agilent
deviation
chassis 24
phase 61, 65, 100
PSK 74, 75, 100
module driver 12
Isolation 99
SCPI commands 79
soft front panel operation 77
Asymmetry 97
dimensions 5, 6, 96
duty cycle 30, 38, 39, 40, 43, 47, 48,
J
B
52, 58, 64, 89, 97, 100
jitter 97, 98
browser 10
U2761A User’s Guide
103
Index
L
limits
Sweep 80
sweep
outlook 3
mode 82
amplitude 27, 33
duty cycle 30
frequency 38
protection 99
PSK
function 27, 30
offset voltage 31
output termination 31
units selection 32
L-Mount kit 7, 24
carrier frequency 73
rate 74
triggering
External 85, 87
input signal 88, 101
Internal 85, 86, 89
O
output
duty cycle 47
control 41
waveform 45
function 26
SCPI commands 42
sweep 80, 83
termination 36
units 35
warranty 96
weight 96
resolution 99
P
phase noise 97
PM
carrier frequency 63
modulating waveform 64
modulating waveform frequency 64
phase deviation 65, 100
SCPI commands 65
sampling rate 98
settling time 98
shock 96
spurious 97, 101
start frequency 81
stop frequency 81
storage humidity 96
storage temperature 96
prerequisites 10
104
U2761A User’s Guide
www.agilent.com
Contact us
To obtain service, warranty or technical
support assistance, contact us at the fol-
lowing phone numbers:
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(tel) 800 829 4444
Canada:
(tel) 877 894 4414
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(tel) 800 810 0189
Europe:
(fax) 800 829 4433
(fax) 800 746 4866
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(tel) 31 20 547 2111
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(tel) (81) 426 56 7832 (fax) (81) 426 56
7840
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(tel) (080) 769 0800
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(tel) (305) 269 7500
Taiwan:
(fax) (080) 769 0900
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Other Asia Pacific Countries:
(tel) (65) 6375 8100
(fax) (65) 6755 0042
Or visit Agilent worldwide web at:
www.agilent.com/find/assist
Product specifications and descriptions in
this document are subject to change with-
out notice. Always refer to Agilent web site
for latest revision.
© Agilent Technologies, Inc., 2008-2009
Third Edition, January 31, 2009
U2761-90000
Agilent Technologies
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