Fluke 271 Operating Manual

®

271

Programmable 10 MHz DDS Function Generator

Users Manual

January 2005

© 2005 Fluke Corporation, All rights reserved. Printed in USA
All product names are trademarks of their respective companies.

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Users Manual

LIMITED WARRANTY AND LIMITATION OF LIABILITY

Each Fluke product is warranted to be free from defects in material and workmanship under normal use and
service. The warranty period is one year and begins on the date of shipment. Parts, product repairs, and
services are warranted for 90 days. This warranty extends only to the original buyer or end-user customer of
a Fluke authorized reseller, and does not apply to fuses, disposable batteries, or to any product which, in
Fluke's opinion, has been misused, altered, neglected, contaminated, or damaged by accident or abnormal
conditions of operation or handling. Fluke warrants that software will operate substantially in accordance
with its functional specifications for 90 days and that it has been properly recorded on non-defective media.
Fluke does not warrant that software will be error free or operate without interruption.

Fluke authorized resellers shall extend this warranty on new and unused prod ucts to end-user customers
only but have no authority to extend a greater or different warranty on behalf of Fluke. Warranty support is
available only if product is purchased through a Fluke authorized sales outlet or Buyer has paid the
applicable international price. Fluke reserves the right to invoice Buyer for importation cost s of
repair/replacement parts when product purchased in one country is submitted for repair in another countr y.

Fluke's warranty obligation is limited, at Fluke's option, to refund of the purchase price, free of charge repair,
or replacement of a defective product which is returned to a Fluke authorized service center within the
warranty period.

To obtain warranty service, contact your nearest Fluke authorized service center to obtain return
authorization information, then send the product to that service center, with a description of the difficulty,
postage and insurance prepaid (FOB Destination). Fluke assumes no risk for damage in transit. Following
warranty repair, the product will be returned to Buyer, transportation prepaid (FOB Destination). If Fluke
determines that failure was caused by neglect, misuse, contamination, alteration, accident, or abnormal
condition of operation or handling, including overvoltage failures caused by use outsid e th e product’s
specified rating, or normal wear and tear of mechanical components, Fluke will provide an estimate of repair
costs and obtain authorization before commencing the work. Following repair, the product will be returned to
the Buyer transportation prepaid and the Buyer will be billed for the repair and return transportation charges
(FOB Shipping Point).

THIS WARRANTY IS BUYER'S SOLE AND EXCLUSIVE REMEDY AND IS IN LIEU OF ALL OTHER
WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY
OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. FLUKE SHALL NOT BE LIABLE
FOR ANY SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES OR LOSSES,
INCLUDING LOSS OF DATA, ARISING FROM ANY CAUSE OR THEORY.

Since some countries or states do not allow limitation of the term of an implied warranty, or exclusion or
limitation of incidental or consequential damages, the limitations and exclusions of this warranty may not
apply to every buyer. If any provision of this Warranty is held invalid or unenforceable by a court or other
decision-maker of competent jurisdiction, such holding will not affect the validity or enforceability of any other
provision.

Fluke Corporation
P.O. Box 9090
Everett, WA 98206-9090
U.S.A.

Fluke Europe B.V.
P.O. Box 1186
5602 BD Eindhoven
The Netherlands

11/99
To register your product online, visit register.fluke.com

Safety

This function generator is a Safety Class I instrument according to IEC classification and
has been designed to meet the requirements of EN61010-1 (Safety Requirements for
Electrical Equipment for Measurement, Control and Laboratory Use). It is an Installation
Category II instrument intended for operation from a normal single phase supply.

This instrument has been tested in accordance with EN61010-1 and has been supplied in
a safe condition. This instruction manual contains some information and warnings which
have to be followed by the user to ensure safe operation and to retain the instrument in a
safe condition.

This instrument has been designed for indoor use in a Pollution Degree 2 environment in
the temperature range 5 °C to 40 °C, 20 % - 80 % RH (non-condensing). It may
occasionally be subjected to temperatures between +5 °C and -10 °C without degradation
of its safety. Do not operate the instrument while condensation is present.

Use of this instrument in a manner not specified by these instructions may impair the
safety protection provided. Do not operate the instrument outside its rated supply
voltages or environmental range.

Warning

To avoid the possibility of electric shock:

• This instrument must be earthed.

• Any interruption of the mains earth conductor inside or

outside the instrument will make the instrument
dangerous. Intentional interruption is prohibited. The
protective action must not be negated by the use of an
extension cord without a protective conductor.

• When the instrument is connected to its supply, terminals
may be live and opening the covers or removal of parts
(except those to which access can be gained by hand) is
likely to expose live parts.

• The apparatus shall be disconnected from all voltage
sources before it is opened for any adjustment,
replacement, maintenance or repair.

• Any adjustment, maintenance and repair of the opened
instrument under voltage shall be avoided as far as
possible and, if inevitable, shall be carried out only by a
skilled person who is aware of the hazard involved.

• Make sure that only fuses with the required rated current
and of the specified type are used for replacement. The use
of makeshift fuses and the short-circuiting of fuse holders
is prohibited.

Caution

If the instrument is clearly defective, has been subject to
mechanical damage, excessive moisture or chemical corrosion
the safety protection may be impaired and the apparatus should
be withdrawn from use and returned for checking and repair.

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Note

This instrument uses a Lithium button cell for non-volatile memory battery
back-up. Typical battery life is 5 years. In the event of replacement
becoming necessary, replace only with a cell of the correct type, a 3 V
Li/Mn0

20 mm button cell type 2032. Do not mix with solid waste stream.

2

Do not cut open, incinerate, expose to temperatures above 60 °C or attempt
to recharge. Used batteries should be disposed of by a qualified recycler or
hazardous materials handler. Contact your authorized Fluke Service
Center for recycling information.

Caution

Do not wet the instrument when cleaning it and in particular use
only a soft dry cloth to clean the LCD window.

The following symbols are used on the instrument and in this manual:

Caution - refer to the accompanying documentation,
incorrect operation may damage the instrument.

Terminal connected to chassis ground.
Mains supply OFF.
Mains supply ON.
Alternating current.

Warning - hazardous voltages may be present.

ii

EMC Compliance

This instrument meets the requirements of the EMC Directive 89/336/EEC.
Compliance was demonstrated by meeting the test limits of the following standards:

Emissions

EN61326 (1998) EMC product standard for Electrical Equipment for Measurement,
Control and Laboratory Use. Test limits used were:

a) Radiated: Class B
b) Conducted: Class B
c) Harmonics:

Immunity

EN61326 (1998) EMC product standard for Electrical Equipment for Measurement,
Control and Laboratory Use. Test methods, limits and performance achieved were:

a) EN61000-4-2 (1995)

b) EN61000-4-3 (1997)

c) EN61000-4-11 (1994)

d) EN61000-4-4 (1995)

e) EN61000-4-5 (1995)

f) EN61000-4-6 (1996)

According to EN61326 the definitions of performance criteria are:

The instrument is Class A by product category.

EN61000-3-2 (2000) Class A

Electrostatic Discharge: 4 kV air, 4 kV contact

Electromagnetic Field: 3 V/m, 80 % AM at 1 kHz

Voltage Interrupt: 1 cycle, 100 %

Fast Transient: 1 kV peak (ac line), 0.5 kV peak (signal lines
and RS232/GPIB ports)

Surge: 0.5 kV (line to line), 1 kV (line to ground)

Conducted RF: 3 V, 80 % AM at 1kHz (ac line only; signal
connections <3 m not tested)

Performance A.

Performance A.

Performance A.

Performance A.

Performance A.

Performance A.

Performance criterion A: ‘During test normal performance within the specification

limits.’

Performance criterion B: ‘During test, temporary degradation, or loss of function or

performance which is self-recovering’.

Performance criterion C: ‘During test, temporary degradation, or loss of function or

performance which requires operator intervention or system
reset occurs.’

To ensure continued compliance with the EMC directive the
following precautions should be observed:

a) connect the generator to other equipment using only high
quality, double-screened cables.

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Cautions

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b) after opening the case for any reason ensure that all signal
and ground connections are remade correctly before replacing
the cover. Always ensure all case screws are correctly refitted
and tightened.

c) In the event of part replacement becoming necessary, only
use components of an identical type. Refer to the Service
Manual.

iv

Table of Contents

Chapter Title Page

Introduction and Specifications .................................................................... 1-1

Introduction........................................................................................................ 1-2

Principal features........................................................................................... 1-2

Specifications..................................................................................................... 1-4

Waveforms .................................................................................................... 1-4

Sine............................................................................................................ 1-4

Square........................................................................................................ 1-4

Triangle..................................................................................................... 1-4

Positive and Negative Ramps.................................................................... 1-4

Positive and Negative Pulses .................................................................... 1-5

Multi-level Square Wave .......................................................................... 1-5

Arbitrary.................................................................................................... 1-5

Hop............................................................................................................ 1-5

Noise ......................................................................................................... 1-5

Modulation Modes......................................................................................... 1-5

Continuous ................................................................................................ 1-5

Trigger and burst....................................................................................... 1-6

Gated......................................................................................................... 1-6

Sweep........................................................................................................ 1-6

Amplitude Modulation.............................................................................. 1-6

Frequency Shift Keying (FSK) ................................................................. 1-6

Start/Stop Phase ........................................................................................ 1-7

Trigger Generator...................................................................................... 1-7

Outputs .......................................................................................................... 1-7

Main Output.............................................................................................. 1-7

Aux Out..................................................................................................... 1-7

Trig/Sweep Out......................................................................................... 1-7

Inputs............................................................................................................. 1-8

Ext Trig..................................................................................................... 1-8

VCA In...................................................................................................... 1-8

Phase locking................................................................................................. 1-8

Clock In/Out.............................................................................................. 1-8

Sync Out.................................................................................................... 1-8

Interfaces ....................................................................................................... 1-8

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General .......................................................................................................... 1-8

2 Installation ........................................................................................... 2-1

Mains Operating Voltage................................................................................... 2-2

Fuse.................................................................................................................... 2-2

Mains Lead ........................................................................................................ 2-2

Mounting............................................................................................................ 2-2

3 Connections......................................................................................... 3-1

Front Panel Connections.................................................................................... 3-2

MAIN OUT................................................................................................... 3-2

AUX OUT..................................................................................................... 3-2

EXT TRIG..................................................................................................... 3-2

Rear Panel Connections..................................................................................... 3-2

CLOCK IN/OUT........................................................................................... 3-2

VCA IN ......................................................................................................... 3-3

SYNC OUT................................................................................................... 3-3

TRIG/SWEEP OUT ...................................................................................... 3-3

RS232............................................................................................................ 3-4

GPIB (IEEE-488) .......................................................................................... 3-4

4 General Operation............................................................................... 4-1

Introduction........................................................................................................ 4-2

DDS Principles .................................................................................................. 4-2

Switching On ..................................................................................................... 4-2

Display Contrast............................................................................................ 4-3

Keyboard ....................................................................................................... 4-3

Principles of Editing .......................................................................................... 4-4

5 Main Generator Operation.................................................................. 5-1

Introduction........................................................................................................ 5-2

Main Generator Parameters ............................................................................... 5-2

Frequency...................................................................................................... 5-2

Output Level.................................................................................................. 5-3

Output Impedance ......................................................................................... 5-4

DC Offset ...................................................................................................... 5-4

DC Output ..................................................................................................... 5-5

Symmetry ...................................................................................................... 5-5

Warning and Error Messages............................................................................. 5-6

The Auxiliary Output......................................................................................... 5-7

Auxiliary Output Phase ................................................................................. 5-8

Waveform Generation Options.......................................................................... 5-9

Square Wave Generation............................................................................... 5-9

Filter .............................................................................................................. 5-9

Auxiliary Output............................................................................................ 5-10

Frequency Stop.............................................................................................. 5-10

Trigger/Sweep Output................................................................................... 5-10

6 Sweep Operation................................................................................. 6-1

Introduction........................................................................................................ 6-2

Connections for Sweep Operation..................................................................... 6-2

Setting Sweep Span and Markers ...................................................................... 6-2

vi

Contents (continued)

Setting Sweep Mode, Ramp Time and Source .................................................. 6-3

Frequency Stepping Resolution......................................................................... 6-4

7 Triggered Burst and Gate................................................................... 7-1

Introduction........................................................................................................ 7-2

Internal Trigger Generator............................................................................. 7-2

External Trigger Input................................................................................... 7-2

Triggered Burst.................................................................................................. 7-2

Trigger Source............................................................................................... 7-3

Burst Count.................................................................................................... 7-3

Start/Stop Phase............................................................................................. 7-3

Gated Mode........................................................................................................ 7-4

Gate Source ................................................................................................... 7-4

8 Amplitude Modulation......................................................................... 8-1

Introduction........................................................................................................ 8-2

Amplitude Modulation (Internal)....................................................................... 8-2

Modulation Frequency................................................................................... 8-2

Modulation Depth.......................................................................................... 8-2

Modulation Waveform .................................................................................. 8-3

VCA (External).................................................................................................. 8-3

9 FSK ....................................................................................................... 9-1

Introduction........................................................................................................ 9-2

Frequency Setting.......................................................................................... 9-2

Trigger Source............................................................................................... 9-2

10 Special Waveforms ............................................................................. 10-1

Staircase............................................................................................................. 10-2

Arbitrary............................................................................................................. 10-3

Recalling Arbitrary Waveforms .................................................................... 10-3

Storing Arbitrary Waveforms........................................................................ 10-3

Noise.................................................................................................................. 10-4

11 Hop ....................................................................................................... 11-1

Introduction........................................................................................................ 11-2

Setting each Waveform Step.............................................................................. 11-2

Defining the Sequence and Timing.................................................................... 11-2

Running the Sequence ....................................................................................... 11-3

Timing Considerations....................................................................................... 11-3

Saving Hop Settings........................................................................................... 11-4

12 System Operations.............................................................................. 12-1

Storing and Recalling Set-Ups........................................................................... 12-1

System Settings .................................................................................................. 12-2

Cursor Style................................................................................................... 12-2

Rotary Control............................................................................................... 12-2

Power Up Setting........................................................................................... 12-2

CLOCK IN/OUT Setting............................................................................... 12-2

13 Synchronizing Generators.................................................................. 13-1

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Introduction........................................................................................................ 13-2

Synchronizing Principles................................................................................... 13-2

Connections for Synchronization....................................................................... 13-2

Generator Set-Ups.............................................................................................. 13-2

Synchronizing.................................................................................................... 13-3

14 Calibration............................................................................................ 14-1

Introduction........................................................................................................ 14-2

Equipment Required.......................................................................................... 14-2

Calibration Procedure ........................................................................................ 14-2

Setting the Password...................................................................................... 14-2

Using the Password to Access Calibration or Change the Password ............ 14-3

Calibration Routine ....................................................................................... 14-3

15 Application Examples......................................................................... 15-1

Introduction........................................................................................................ 15-2

Default Settings.................................................................................................. 15-2

Simple Main Generator Operation..................................................................... 15-2

Pulse Trains........................................................................................................ 15-2

Low Duty Cycle Pulse Trains............................................................................ 15-3

Multiple Pulses .................................................................................................. 15-4

Variable Transition Pulse Waveforms............................................................... 15-4

Slew-Limited Transitions.............................................................................. 15-4

Band-Limited Pulses ..................................................................................... 15-5

Pulses With Overshoot.................................................................................. 15-5

16 Remote Operation ............................................................................... 16-1

Remote Operation.............................................................................................. 16-2

Address and Baud Rate Selection.................................................................. 16-2

Remote/Local Operation ............................................................................... 16-2

RS232 Interface............................................................................................. 16-3

Single Instrument RS232 Connections ..................................................... 16-3

Addressable RS232 Connections.............................................................. 16-3

RS232 Character Set................................................................................. 16-4

Addressable RS232 Interface Control Codes............................................ 16-4

Full List of Addressable RS232 Interface Control Codes......................... 16-6

GPIB Interface............................................................................................... 16-6

GPIB Subsets ............................................................................................ 16-6

GPIB IEEE Std. 488.2 Error Handling ..................................................... 16-6

GPIB Parallel Poll..................................................................................... 16-7

Status Reporting........................................................................................ 16-7

Standard Event Status and Standard Event Status Enable Registers......... 16-8

Status Byte Register and Service Request Enable Register ...................... 16-8

Status Model.................................................................................................. 16-9

Power on Settings...................................................................................... 16-9

Remote Commands............................................................................................ 16-10

RS232 Remote Command Formats............................................................... 16-10

GPIB Remote Command Formats................................................................. 16-10

Command List............................................................................................... 16-11

Function Selection......................................................................................... 16-12

Main Generator Parameters........................................................................... 16-12

Sweep Parameters.......................................................................................... 16-12

Trigger and Gate ............................................................................................ 16-13

viii

Contents (continued)

AM Parameters.............................................................................................. 16-13

FSK Parameters............................................................................................. 16-13

Staircase and Arbitrary Waveforms .............................................................. 16-14

Waveform Generation Options...................................................................... 16-14

Hop Commands............................................................................................. 16-14

System Commands........................................................................................ 16-15

Status Commands.......................................................................................... 16-15

Miscellaneous Commands............................................................................. 16-16

Phase Locking Commands ............................................................................ 16-16

Remote Command Summary............................................................................. 16-17

Appendices

A AC Supply Voltage Settings........................................................................ A-1

B DDS Operation and Further Waveform Considerations ............................. B-1

C Application Information Notes.................................................................... C-1

D Warning and Error Messages ...................................................................... D-1

E Factory System Defaults ............................................................................. E-1

F Waveform Manager Plus............................................................................. F-1

G Front and Rear Panels.................................................................................. G-1

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x

Chapter 1

Introduction and Specifications

Title Page

Introduction........................................................................................................ 1-2

Principal features ........................................................................................... 1-2

Specifications..................................................................................................... 1-4

Waveforms .................................................................................................... 1-4

Sine............................................................................................................ 1-4

Square........................................................................................................ 1-4

Triangle ..................................................................................................... 1-4

Positive and Negative Ramps.................................................................... 1-4

Positive and Negative Pulses .................................................................... 1-5

Multi-level Square Wave .......................................................................... 1-5

Arbitrary.................................................................................................... 1-5

Hop............................................................................................................ 1-5

Noise ......................................................................................................... 1-5

Modulation Modes......................................................................................... 1-5

Continuous ................................................................................................ 1-5

Trigger and burst ....................................................................................... 1-6

Gated ......................................................................................................... 1-6

Sweep ........................................................................................................ 1-6

Amplitude Modulation.............................................................................. 1-6

Frequency Shift Keying (FSK) ................................................................. 1-6

Start/Stop Phase ........................................................................................ 1-7

Trigger Generator...................................................................................... 1-7

Outputs .......................................................................................................... 1-7

Main Output .............................................................................................. 1-7

Aux Out..................................................................................................... 1-7

Trig/Sweep Out ......................................................................................... 1-7

Inputs ............................................................................................................. 1-8

Ext Trig ..................................................................................................... 1-8

VCA In...................................................................................................... 1-8

Phase locking................................................................................................. 1-8

Clock In/Out.............................................................................................. 1-8

Sync Out.................................................................................................... 1-8

Interfaces ....................................................................................................... 1-8

General .......................................................................................................... 1-8

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Introduction

This Programmable Function Generator uses direct digital synthesis to provide high
performance and extensive facilities at a breakthrough price. It can generate a variety of
waveforms between 0.1 mHz and 10 MHz with a resolution of 7 digits and an accuracy
better than 10 ppm.

Principal features

Direct digital synthesis for accuracy & stability

Direct digital synthesis (DDS) is a technique for generating waveforms digitally using a
phase accumulator, a look-up table and a DAC. The accuracy and stability of the
resulting waveforms are related to that of the crystal master clock.

In addition the DDS generator offers high spectral purity, low phase noise and excellent
frequency agility.

A wide range of waveforms

High quality sine, square and pulse waveforms can be generated over the full frequency
range of 0.1 mHz to 10 MHz.

Triangle ramp and multi-level square waveforms also be generated over limited
frequency ranges.

Variable symmetry or duty-cycle is available for all standard waveforms.

Arbitrary waveform capability

Arbitrary waveforms can be loaded via the digital interfaces and then used in a similar
way to the standard waveforms.

Up to five arbitrary waveforms of 1024 10-bit words can be stored in non-volatile
memory. The maximum waveform clock frequency is 27.48 MHz.

This facility considerably expands the versatility of the instrument, making it suitable for
the generation of highly complex waveform patterns.

In addition, numerous complex waveforms are pre-defined in ROM, including commonly
used wave shapes such as sin(x)/x, exponentially decaying sine wave, etc. Further wave
shapes will be added to the library in response to customer requests.

Sweep

All waveforms can be swept over their full frequency range at a rate variable between
10 milliseconds and 15 minutes. Sweeps are fully phase continuous.

Sweeps can be linear or logarithmic, single or continuous. Single sweeps can be triggered
from the front panel, the trigger input or the digital interfaces. Two sweep markers are
provided.

1-2

Amplitude modulation

AM is available for all waveforms and is variable in 1 % steps up to 100 %. An internal
AM source is incorporated. Modulation may also be controlled by an external generator.

Frequency shift keying

FSK provides phase coherent switching between two selected frequencies at a rate
defined by the switching signal source.

Introduction and Specifications

Introduction 1

The rate can be set from dc to 50 kHz internally, or dc to 1 MHz externally.

Triggered burst and gated modes

All waveforms are available as a triggered burst whereby each positive edge of the trigger
signal will produce one burst of the carrier, starting and stopping at the phase angle
specified by the start-stop phase setting.

The number of cycles in the burst can be set between 0.5 and 1023. The gated mode turns
the output signal on when the gating signal is high and off when it is low.

Both triggered and gated modes can be operated from the internal trigger generator
(0.005 Hz to 50 kHz) or from an external source (dc to 1 MHz).

Waveform hop and noise

The generator can be set up to hop between a number of different waveform settings,
either at a predetermined rate or in response to a manual trigger.

Up to 16 different hop waveforms can be defined in terms of frequency, amplitude,
function, offset and duration. Duration is variable in 1 ms steps up to 60 s. The generator

can also be set to simulate random noise within the bandwidth 0.03 Hz to 700 kHz with

adjustable amplitude and offset.

Multiple phase-locked generators

The signals from the reap panel

CLOCK IN/OUT socket and SYNC OUT sockets can

be used to phase lock two or more generators.

Phase locked generators can be used to generate multi-phase waveforms or locked
waveforms of different frequencies.

Easy and convenient to use

All of the main generator parameters are clearly displayed together on a backlit liquid
crystal display (LCD) with 4 rows of 20 characters. Sub-menus are used for the
modulation modes and other complex functions.

All parameters can be entered directly from the numeric keypad. Alternatively most
parameters can be incremented or decremented using the rotary encoder.

This system combines quick and easy numeric data entry with quasi-analogue adjustment
when required.

Fully programmable via addressable RS232 and GPIB interfaces

The generator has RS-232 and GPIB (IEEE-488) interfaces which can be used for remote
control of all of the instrument functions and for downloading arbitrary waveforms.

As well as operating in conventional RS-232 mode the serial interface can be used in
addressable mode whereby up to 32 instruments can be linked to a single PC serial port.

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Specifications

Specifications apply at 18- 28 °C after one hour warm-up, at maximum output into 50 Ω.

Waveforms

Standard waveforms include sine, square, triangle, dc, positive ramp, negative ramp,
positive pulse, negative pulse and multi-level square wave. In addition the instrument
provides arbitrary waveforms (arb) and pseudo-random noise.

Sine

Range: 0·1 mHz to 10 MHz
Resolution: 0·1 mHz or 7 digits
Symmetry control: 1 to 99 % (0.1 % resolution) from 0.1 mHz to 10 MHz.
Accuracy: 10 ppm for 1 year
Temperature stability: Typically <1 ppm/ºC outside 18 to 28 °C
Output Level:
Harmonic distortion: <0.3 % THD to 100 kHz;

Non−harmonic spurious:

2.5 mV to 10 V p−p into 50 Ω

<–50 dBc to 300 kHz
<–35dBc to 10 MHz

<–65 dBc to 1 MHz,
<–65 dBc +6 dB/octave 1 MHz to 10 MHz

Square

Range: 0.1 mHz to 10 MHz
Resolution: 0.1 mHz or 7 digits
Symmetry control: 1 to 99 % (0.1 % resolution) from 0.1 mHz to 30 kHz

Accuracy: 10 ppm for 1 year
Output level:
Rise and fall times: <22 ns
Aberrations: <5 % +2 mV

Triangle

Range: 0.1 mHz to 100 kHz
Resolution: 0.1 mHz or 7 digits
Symmetry control: 1 to 99 % (0.1 % resolution) from 0.1 mHz to 100 kHz
Accuracy: 10 ppm for 1 year
Output level:
Linearity error: <0.5 % to 30 kHz

Positive and Negative Ramps

Range: 0.1 mHz to 100 kHz
Resolution: 0.1 mHz (7 digits)
Symmetry Control: 1 to 99 % (0.1 % resolution) from 0.1 mHz to 100 kHz
Accuracy: 10 ppm for 1 year
Output Level:
Linearity Error: <0.5 % to 30 kHz

20 % to 80 % (0.1 % resolution) from 30 kHz to 10 MHz

2.5 mV to 10 V p−p into 50 Ω

2.5 mV to 10 V p−p into 50 Ω

2.5 mV to 10 V p−p into 50 Ω

1-4

Introduction and Specifications

Specifications 1

Positive and Negative Pulses

Range: 0.1 mHz to 10 MHz
Resolution: 0.1 mHz or 7 digits
Symmetry control: 1 to 99 % (0.1 % resolution) from 0.1 mHz to 30 kHz

20 to 80 % (0.1 % resolution) from 30 kHz to 10 MHz
Accuracy: 10 ppm for 1 year
Output level: 2.5 mV to 10 V p-p into 50 Ω
Rise and fall times: <22 ns
Aberrations: <5 % +2 mV

Multi-level Square Wave

Maximum of 16 steps of discrete amplitude (10 bit resolution) and duration (1 to 1024
samples). Allows generation of three-level square wave, staircase, multiplexed LCD
driver signals, etc.

Range: All waveform points are continuously output up to

approximately 27 kHz, above which sampling will introduce

an uncertainty of 1 clock edge (1 clock = 36 ns).

Output level: 5 mV to 20 V p-p into an open circuit.
Rise and fall times: <22 ns

Arbitrary

A number of frequently required waveforms are pre-programmed in the internal read­only memory (ROM). Waveforms may also be downloaded via the RS232 or GPIB
interfaces and stored in the internal non-volatile random-access memory (RAM).

Frequency range: 0.1 mHz to 10 MHz

Output level: 5 mV to 20 V p-p into an open circuit.
Sampling frequency: 27.48 MHz
Number of samples: 1024
Sample levels: 1024 (10 bits)

Hop

Up to 16 different waveforms can be output in sequence at a rate determined by either the
internal timer, an external trigger a remote command, or from the keyboard. Each
waveform can be set to any wave shape (except noise), frequency, amplitude and offset.
Frequency-only changes are phase-continuous.

Noise

White noise output with a typical -3 dB bandwidth of 0.03 Hz to 700 kHz. Amplitude and
offset are adjustable. Noise can only be used with gated and AM modes.

Waveform points are continuously output up to

approximately 27 kHz, above which they are sampled.

Modulation Modes

Continuous

Continuous cycles of the selected waveform are output at the programmed frequency.

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Trigger and burst

Phase-coherent signal keying: each positive edge of the trigger signal will produce one
burst of the carrier, starting and stopping at the phase angle specified by the start/stop
phase setting.

Carrier frequency: 0.1 mHz to >1 MHz
Carrier waveforms: All
Number of cycles: 1 to 1023 (resolution 1 cycle)

or 0.5 to 511.5 (resolution 0.5 cycle).

Trigger repetition rate: dc to 50 kHz internal, dc to 1 MHz external.
Source: Manual (front panel key), internal trigger generator, external

signal or remote interface.

Gated

Non-phase coherent signal keying: the output carrier wave is on while the gate signal is
high and off while it is low.

Carrier frequency: From 0.1 mHz to 10 MHz.
Carrier waveforms: All
Trigger repetition rate: dc to 50 kHz internal, dc to 1 MHz external.
Gate signal source: Manual (front panel key), internal trigger generator, external

signal or remote interface.

Sweep

Carrier waveforms: All
Sweep modes: Linear or logarithmic, single or continuous.
Sweep width: From 0.1 mHz to 10 MHz in one range. Phase continuous.

Sweep time: 10 ms to 999 s with 3 digit resolution.
Markers: Two, variable during sweep, available at the rear panel

Sweep trigger source: The sweep may be free run or triggered manually (front

Amplitude Modulation

Carrier frequency: From 0.1 mHz to 10 MHz.
Carrier waveforms: All.
Depth: Variable 0 to 100% typical, resolution 1 %.
Internal source: 1 kHz fixed sine wave or 0.005 Hz to 50 kHz square wave.

External: See VCA In below.

Frequency Shift Keying (FSK)

Phase coherent switching between two selected frequencies at a rate defined by the
switching signal source.

Carrier frequency: From 0.1 mHz to 10 MHz.
Carrier waveforms: All.
Switch repetition rate: dc to 50 kHz internal, dc to 1 MHz external.
Switching signal source: Manual (front panel key), internal trigger generator, external

Start and stop frequency may be set independently.

socket.

panel key), by an external signal or through a remote

interface.

signal or remote interface.

1-6

Introduction and Specifications

Specifications 1

Start/Stop Phase

The phase relationship between the

MAIN OUT and AUX OUT sockets is determined by

the start/stop phase setting.

Carrier frequency: 0.1 mHz to >1 MHz.
Carrier waveforms: All.
Range: -360 to +360 degrees.
Resolution: 1 degree.
Accuracy: Typically 1 degree to 30 kHz.

Trigger Generator

Internal source 0.005 Hz to 50 kHz square wave, adjustable in 20 µs steps with 3 digit
resolution. Available for external use from a rear panel socket.

Outputs

Main Output

Output Impedance: 50 Ω or 600 Ω
Amplitude: 5 mV to 20 V p-p into an open circuit,

2.5 mV to 10V p-p into 50 Ω/600 Ω.

Output can be specified as VhiZ (open circuit value) or V

(voltage into characteristic impedance) in p-p, r.m.s. or dBm.

Amplitude accuracy: ±3 % ±1 mV at 1 kHz into 50 Ω/600 Ω.
Amplitude flatness: ±0.2 dB to 500 kHz; ±1 dB to 10 MHz.
DC offset range: ±10 V. The dc offset plus signal peak is limited to ±10 V

from 50 Ω/600 Ω.

DC offset accuracy: typically ±3 % ±10 mV, unattenuated.
Resolution: 3 digits for both amplitude and dc offset.
Pulse aberrations: <5 % + 2 mV.

Aux Out

CMOS/TTL levels with symmetry and frequency of main output. The phase relationship
between

Trig/Sweep Out

The function of this output is automatically determined by the generator operating mode.
Except in sweep and hop modes the output is that of the internal trigger generator, a fixed
amplitude square wave, the frequency of which is set in the
The rising edge of the trigger generator initiates trigger, gate and burst modes.

In sweep mode the output is a 3-level waveform, changing from high (4 V) to low (0 V)
at the start of the sweep, with narrow 1 V pulses at marker points.

In hop mode the output goes low on entry to each waveform step and high after the new
frequency and wave shape of that step have been set.

Output impedance is 1 kΩ.

MAIN OUT and AUX OUT is determined by the start/stop phase setting.

trig or gate menu.

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Inputs

Ext Trig

Frequency range: dc to 1 MHz.
Signal range: Threshold nominally TTL level; maximum input ±10 V.
Minimum pulse width: 50 ns for trigger, gate and FSK modes;

1 ms for sweep and hop modes.

Input impedance: 10 kΩ

VCA In

Frequency range: DC - 100 kHz.

Signal range: 2.5 V for 100% level change at maximum output.

Input impedance: typically 6 kΩ.

Phase locking

The signals from these sockets are used to phase lock two or more generators.

Clock In/Out

TTL/CMOS threshold level as an input.
Output logic levels nominally 1 V and 4 V from typically 50 Ω as an output.

Sync Out

TTL/CMOS logic levels from typically 50 Ω.

Interfaces

Full remote control facilities are available through the RS232 or GPIB interfaces.

RS232: Variable Baud rate, 9600 Baud maximum. 9-pin D-

GPIB (IEEE-488): Conforms with IEEE488.1 and IEEE488.2

General

Display: 20 character x 4 row alphanumeric LCD.
Data Entry: Keyboard selection of mode, waveform etc.

Stored Settings: Up to 9 complete instrument set-ups may be stored and

Size: 3U (130mm) high;

Weight: 4.1 kg (9 lb)
Power: 100 V ac, 110-120 V ac or 220-240 V ac ±10 %,

Temperature range: operating: +5 to 40 °C, 20-80 % RH.

Environmental: Indoor use at altitudes up to 2000 m,

connector.

As well as operating in a conventional RS232 mode the

interface can be operated in addressable mode whereby up to

32 instruments can be addressed from one RS232 port.

Value entry direct by numeric keys or by rotary control.

recalled from battery-backed memory.

half-rack (212mm) wide;

330mm deep.

50/60 Hz, adjustable internally;

40 VA max.

Installation category II.

storage: -20 to +60 °C

1-8

Introduction and Specifications

Specifications 1

Pollution degree 2.

Options: 19 inch rack mounting kit.
Safety: Complies with EN61010-1.
EMC: Complies with EN61326.

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1-10

Chapter 2

Installation

Title Page

Mains Operating Voltage................................................................................... 2-2

Fuse.................................................................................................................... 2-2

Mains Lead ........................................................................................................ 2-2

Mounting............................................................................................................ 2-2

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Mains Operating Voltage

Check that the instrument operating voltage marked on the rear panel is correct for the
local supply. If it is necessary to change the operating voltage, follow the procedure
described in the appendix.

Fuse

Ensure that the correct mains fuse is fitted for the set operating voltage. The correct
mains fuse types are listed in Appendix A.

Mains Lead

Warning

To avoid the possibility of electric shock, this instrument must
be earthed. Any interruption of the mains earth conductor
inside or outside the instrument will make the instrument
dangerous. Intentional interruption is prohibited. The protective
action must not be negated by the use of an extension cord
without a protective conductor.

When a three core mains lead with bare ends is provided it should be connected as
follows:-

Mounting

This instrument is suitable both for bench use and rack mounting. It is delivered with feet
for bench mounting. The front feet include a tilt mechanism for optimal panel angle.

A rack kit for mounting in a 19 inch rack is available from the manufacturers.

Brown Mains Live
Blue Mains Neutral
Green / Yellow Mains Earth

2-2

Chapter 3

Connections

Title Page

Front Panel Connections.................................................................................... 3-2

MAIN OUT ................................................................................................... 3-2

AUX OUT ..................................................................................................... 3-2

EXT TRIG..................................................................................................... 3-2

Rear Panel Connections ..................................................................................... 3-2

CLOCK IN/OUT ........................................................................................... 3-2

VCA IN ......................................................................................................... 3-3

SYNC OUT ................................................................................................... 3-3

TRIG/SWEEP OUT ...................................................................................... 3-3

RS232 ............................................................................................................ 3-4

GPIB (IEEE-488) .......................................................................................... 3-4

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Front Panel Connections

MAIN OUT

MAIN OUT is the 50 Ω / 600 Ω output from the main generator. It will provide up to 20

V p-p into a high-impedance load or 10 V p-p into a matched 50 Ω / 600 Ω load. It can
tolerate a short circuit for 60 seconds.

To avoid risk of damage to the instrument, do not apply
external voltages to this output.

AUX OUT

AUX OUT is a TTL/CMOS level output synchronous with MAIN OUT. Symmetry is the

same as that set for the main output but the phase relationship between

AUX OUT
AUX OUT logic levels are nominally 0 V and 5 V from typically 50 Ω. AUX OUT will

withstand a short-circuit.

is determined by the PHASE setting specified on the TRIGger menu.

Caution

MAIN OUT and

To avoid risk of damage to the instrument, do not apply
external voltages to this output.

EXT TRIG

EXT TRIG is the external trigger input for trigger, gate, sweep, FSK and hop operating

modes. It is also the input used to synchronize the generator as a slave to an external
master generator.

To avoid risk of damage to the instrument, do not apply
external voltages exceeding ±10 V to this input.

Rear Panel Connections

CLOCK IN/OUT

The function of the

INPUT
OUTPUT

PHASE LOCK

As an output the logic levels are nominally 1 V and 4 V from typically 50 Ω.

CLOCK IN/OUT socket is set from the SYStem menu as follows:

The socket becomes an input for an external clock.
This is the default setting. The internal clock is made
available at the socket. When two or more generators are
synchronized the master is set to
used to drive the
When two or more generators are synchronized the slaves
are set to

PHASE LOCK.

Caution

Caution

OUTPUT and the signal is

CLOCK IN inputs of the slaves.

3-2

CLOCK IN/OUT will withstand a short-circuit.

When used as an input the threshold is TTL/CMOS compatible.

Connections

Rear Panel Connections 3

Caution

To avoid risk of damage to the instrument, do not apply
external voltages exceeding +7.5 V or -2.5 V to this input.

VCA IN

VCA IN is the input socket for external voltage controlled amplitude (VCA). The input
impedance is nominally 6 kΩ. Apply 2.5 V for 100% level change at maximum output.

Caution

To avoid risk of damage to the instrument, do not apply
external voltages exceeding ±10 V to this input.

SYNC OUT

When two or more generators are synchronized the
generator is connected to the

EXT TRIG inputs of slave generators.

SYNC OUT socket on the master

SYNC OUT logic levels are nominally 0 V and 5 V from typically 50 Ω. SYNC OUT

will withstand a short-circuit.

To avoid risk of damage to the instrument, do not apply
external voltages to this output.

TRIG/SWEEP OUT

The function of this output is automatically determined by the generator's operating
mode.

Except in sweep and hop modes the output is that of the internal trigger generator, a fixed
amplitude square wave whose frequency is set on the
rising edge of the trigger generator initiates trigger, burst, gate, etc.

In sweep mode the output is a 3-level waveform, changing from high (4 V) to low (0 V)
at start of sweep, with narrow 1 V pulses at each marker point.

In hop mode the output goes low on entry to each waveform step and high after the new
frequency and wave shape of that step have been set.

Output levels are nominally 0 V and 4 V from 1 kΩ.
a short-circuit.

To avoid risk of damage to the instrument, do not apply
external voltages to this output.

Caution

TRIG or GATE menus. The

TRIG/SWEEP OUT will withstand

Caution

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RS232

The rear panel carries a 9-pin D-connector compatible with addressable RS232 use. The
pin connections are shown below:

Pin Name Description

1 - No internal Connection
2 TXD Transmitted data from instrument
3 RXD Received data to instrument
4 - No internal connection
5 GND Signal ground
6 - No internal connection
7 RXD2 Secondary received data
8 TXD2 Secondary transmitted data
9 GND Signal ground

Pin 2, 3 and 5 may be used as a conventional RS232 interface with XON/XOFF
handshaking. Pins 7, 8 and 9 are additionally used when the instrument is used in
addressable RS232 mode. Signal grounds are connected to instrument ground. The
RS232 address is set from the front panel using the

REMOTE menu.

GPIB (IEEE-488)

The GPIB interface is an option. It is not isolated; the GPIB signal grounds are connected
to the instrument ground.

The implemented subsets are:

The GPIB address is set from the front panel using the

SH1 AH1 T6 TE0 L4 LE0 SR1 RL1 PP1 DC1 DT1 C0 E2

REMOTE menu.

3-4

Chapter 4

General Operation

Title Page

Introduction........................................................................................................ 4-2

DDS Principles .................................................................................................. 4-2

Switching On ..................................................................................................... 4-2

Display Contrast............................................................................................ 4-3

Keyboard ....................................................................................................... 4-3

Principles of Editing .......................................................................................... 4-4

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Introduction

This section is a general introduction to the features and organization of the function
generator, and is intended to be read before using the instrument for the first time.
Detailed operation is covered in later sections starting with chapter 5, Main Generator
Operation.

DDS Principles

Waveforms are generated by direct digital synthesis (DDS). One complete cycle of the
waveform is stored in RAM as 1024 10-bit amplitude values. As the RAM address is
incremented, the waveform values are output to a digital-to-analogue converter (DAC)
which reconstructs the waveform.

Sine waves and triangles are subsequently filtered to smooth the steps in the DAC output.
The frequency of the waveform is determined by the rate at which the RAM addresses

are changed. Further details of how this rate is varied, i.e. how the frequency is changed,
are given later in the DDS Operation section; it is normally sufficient to know that at low
frequencies the addresses are output sequentially but at higher frequencies the addresses
are sampled.

The major advantages of DDS over conventional analogue generation are:

1. Frequency accuracy and stability are those of the crystal oscillator.

2. Frequencies can be set with high resolution from mHz to MHz.

3. The method delivers low phase noise and low distortion.

4. Very wide frequency sweeps are possible.

5. Fast, phase continuous frequency switching.

6. Non-standard waveforms such as multi-level square waves are easily generated.

7. Basic arbitrary waveform capability in the same instrument.

In addition, being a digital technique, it is easier to make every parameter programmable
from the keyboard, or remotely via RS232 or GPIB interfaces.

The fundamental limitation of the DDS technique is that as the generator frequency is
increased, each waveform cycle is constituted from fewer samples. This is not a problem
with sine waves which, because they are filtered, can be produced with low distortion up
to the frequency limit of the generator.

However with DDS square waves and pulse waveforms the uncertainty of one clock edge
sets a practical limit to the upper frequency. On this instrument the generation technique
changes at 30kHz (this limit can be overridden by the user) to make use of a comparator
driven by the DDS sine wave to ensure jitter-free square waves and pulses up to the
frequency limit of the generator.

Ramp and staircase waveforms are, by default, unfiltered (although filtering can be
selected) and therefore become degraded above the upper limit frequencies given in the
specification; all waveforms are, however, available up to the maximum frequency of the
generator.

4-2

Switching On

The power switch is located at the bottom left of the front panel.
At power up the generator displays the installed software revision whilst loading its RAM

with waveforms; if an error is encountered the message

"SYSTEM RAM ERROR,