Thurlby Thandar Instruments TG4001 User Manual

TG4001

40MHz DDS Function/Arbi trary Generator

INSTRUCTION MANUAL

Table of Contents

Introduction 3 Specification 4 Safety 9 EMC 11 Installation 12 Connections 14

Front Panel Connections 14 Rear Panel Connections 15

General 17

Initial Operation 17 Principles of Editing 18 Principles of Operation 19

Function Generator Operation 21

Setting Generator Paramet er s 21 Warnings and Error Messages 23 SYNC Output 24

Sweep Operation 26

General 26 Setting Sweep Parameters 26

Triggered Burst and Gate 30

General 30 Triggered Burst 31 Gated Mode 32

Sync Out in Triggered Burst and Gated Mode 33 Tone Mode 34 Arbitrary Waveform Generat ion 36

Introduction 36

Selecting and Outputting Arbitrary Waveforms 36

Frequency and Amplitude Control with Arbitrary W aveforms 37

Sync Out Settings with Arbitrary Waveforms 37

Output Filter Setting 37 Pulse and Pulse-trains 39

Pulse Set-up 39

Pulse-train Setup 40 Modulation 43

Sum 44 Synchronising Two Generators 45 System Operations from the Ut ility Menu 47 Calibration 49

Equipment Required 49 Calibration Procedure 49 Calibration Routine 50 Remote Calibration 51

Remote Operation 52

Power on Settings 59

Remote Commands 60

Frequency and Period 61 Amplitude and DC Offset 61 Waveform Selection 61 Arbitrary Waveform Define 62 Arbitrary Waveform Inter rogation 62 Mode Commands 62 Input/Output control 63 Modulation Commands 63 Synchronising Commands 63 Status Commands 63

Miscellaneous Commands 64 Remote Command Summary 65 Maintenance 68 Appendix 1. Warning and Error Messages 69 Appendix 2. SYNC OUT Aut om atic Settings 71 Appendix 3. Factory System Defaults 72 Appendix 4. Waveform Manager Plus Arbitrary Waveform Creation and Management Software 73

Introduction

This synthesised programmable func t ion generator has the following features:

• Sinewaves up to 40MHz, squarewaves up to 50MHz

• 11 standard waveforms available plus pulse and arbitrary

• User defined pulses and pulse trains with 10ns resolution

• Arbitrary waveforms up to 100MHz sampling frequency

• Up to 4 arbitrary waveforms of 4 to 64k points with 12 bit vertical resolution

• Triggering, summing and modulation of all output waveforms

• RS232 and USB and optional GPIB interfaces

The instrument uses a combination of direct digital synthesis and variable clock techniques to provide high performance and extensive facilities in a compact instrum ent. It can generate a wide variety of waveforms between 0·1mHz and 50MHz with high resolution and accuracy.

Arbitrary waveforms may be played back with 12 bit vertical resolution and from 4 to 65536 horizontal points.

All waveforms can be swept over their full frequency range at a rate variable between 1 millisecond and 15 minutes. Sweep can be linear or logarithmic, single or continuous. Single sweeps can be triggered from the front panel, the trigger input, or the digital interfaces. A sweep marker is provided.

Amplitude Modulation is available for all waveforms and is controlled from an external generator via the MODULATIO N input socket.

Signal Summing is available for all waveforms and is controlled from an exter nal generator via the SUM input socket.

All waveforms are available as a Triggered Burst whereby each active edge of the trigg er signal will produce one burst of the carrier. The number of cycles in the burst can be set between 1 and

1048575. The Gated mode turns the output sig nal O n when the g at ing signal is true and Off when it is false. Both Triggered and Gated modes can be operated fr om the internal Trigger Generator (0.005Hz to 100kHz), f rom an external source (dc to 1MHz) or by a key press or remote command.

The signals from the REF IN/ O UT sock et and the SYNC OUT socket can be used to phase lock two instruments. This can be used to generate multi−phase waveforms or locked waveforms of different frequencies.

The generator parameters ar e clear ly displayed on a backlit LCD with 4 rows of 20 charact er s. Soft−keys and sub menus are used to guide the user through even the most complex funct ions.

All parameters can be entered directly from the num eric keypad. Alternatively most parameters can be incremented or decremented using t he r otar y contr ol. This system combines quick and easy numeric data entry with quasi−analogue adjustment when required.

The generator has RS232 and USB interfaces as s tandard which can be used f or r emote control of all of the instrument functions or for the down−loading of ar bit r ary waveforms. As well as operating in conventional RS232 mode the serial interf ace can also be us ed in addres sable mode whereby up to 32 instruments can be linked to a single PC serial port.

There is also a GPIB option.

Range:

0·1mHz to 40MHz

Resolution:

0·1mHz or 10 digits

Accuracy:

10 ppm for 1 year

Temperatur e Stability:

Typically <1 ppm/ºC.

Output Level:

2.5mV to 10Vp−p into 50Ω

Harmonic Distortion:

<0.15% THD to 100kHz; <–60dBc to 20kHz

<–50dBc to 1MHz,

<−40dBc to 10MHz

<−30dBc to 40MHz

Non−harmonic Spurii:

<–60dBc to 1MHz, <–60dBc + 6dB/octave 1MHz to 40MHz

Range:

1mHz to 50MHz

Resolution:

1mHz (8 digits)

Accuracy:

10 ppm for 1 year

Output Level:

2.5mV to 10Vp−p into 50Ω

Rise and Fall Times:

<8ns

Range:

0.1mHz to 500kHz

Resolution:

0.1mHz or 10 digits

Accuracy:

10 ppm for 1 year

Output Level:

2.5mV to 10Vp−p into 50Ω

Linearity Error:

<0.1% to 30 kHz

Range:

0.1mHz to 500kHz

Resolution:

0.1mHz (10 digits)

Accuracy:

10 ppm for 1 year

Output Level:

2.5mV to 10Vp−p into 50Ω

Linearity Error:

<0.1% to 30 kHz

Specifications apply at 18−28ºC after 30 minutes warm−up, at maximum output into 50Ω.

WAVEFORMS Standard Waveforms

Sine, square, triangle, DC, positive ramp, negative ramp, sin(x)/x, pulse, pulse train, cosine, haversine, havercosine and 4 user defined Arbitrary waveforms.

Sine, Cosine, Haversine, Havercosine

Specification

Square

Triangle

Ramps and Sin(x)/x

Output Level:

2.5mV to 10Vp−p into 50Ω

Rise and Fall Times:

<8ns

Period:

Range:

40ns to 100s

Resolution:

8 digit

Accuracy:

10 ppm for 1 year

Resolution:

0·001% of period or 10ns, whichever is greater

Resolution:

0·001% of period or 10ns, whichever is greater

minimum waveform size is 4 points

Vertical Resolution:

12 bits

Sample Clock Range:

100mHz to 100MHz

Resolution:

8 digits

Accuracy:

10 ppm for 1 year

Carrier Waveforms:

All standard and arbitrary

waveform. 100Msamples/s for ARB.

Number of Cycles:

1 to 1,048,575

dc to 1MHz external.

External from TRIG IN or remote interface.

frequency and type.

Pulse and Pulse Train

Delay: Range:

Width: Range:

Note that the pulse width and absolute value of the delay may not exceed the pulse period at any time.

Pulse trains of up to 10 pulses may be specified, each pulse having independently defined width, delay and level. The baseline voltage is separately defined and the sequence repetition rate is set by the pulse train period.

Arbitrary

Up to 4 user defined waveforms may be stored in non-volatile memory. Waveforms can be defined by downloading of waveform data via RS232, GPIB or USB.

Waveform Memory Size:

−99·99s to + 99·99s

10ns to 99·99s

4 waveforms – maximum waveform size is 65536 points,

Output Filter

Selectable between 40MHz Elliptic, 20MHz Bessel or none.

Noise

Digital noise generated by a 35-bit linear feedback register clocked at 100MHz. User’s external filter defines bandwidth and response.

OPERATING MODES Triggered Burst

Each active edge of the trigg er s ig nal will produce one burst of the waveform.

Maximum Carrier Frequency: The smaller of 2.5MHz or the maximum for the selected

Trigger Repetition Rate: 0.005Hz to 100kHz internal

Trigger Signal Source: Internal from keyboard or t r igger generator.

Trigger Start/Stop Phase:

± 360° settable with 0.1° resolution, subject t o waveform

Carrier Waveforms:

All standard and arbitrary.

waveform. 100Msamples/s for ARB.

Trigger Repetition Rate:

0.005Hz to 100kHz internal; dc to 1MHz external.

External from TRIG IN or remote interface.

frequency and type.

Carrier Waveforms:

All standard and arbitrary except pulse and pulse train.

Sweep Mode:

Linear or logarithmic, trig gered or continuous.

Sweep Direction:

Up, down, up/down or down/up.

Independent setting of t he star t and stop frequency.

Sweep Time:

1ms to 999s (3 digit resolution).

Marker:

Variable during sweep.

interface.

Carrier Waveforms:

All waveforms except pulse and pulse train.

Frequency List:

Up to 16 frequencies fr om 1m Hz t o 40MHz.

switching mode.

External from TRIG IN or remote interface.

again.

when the trigger signal goes tr ue again.

again.

Gated

Waveform will run while the Gate signal is true and stop while false.

Maximum Carrier Frequency: The smaller of 2.5MHz or the maximum for the selected

Gate Signal Source: Internal from keyboard or t r igger generator.

Gate Start/Stop Phase:

Sweep

Frequency sweep capability is provided for both standard and arbitrary waveforms. Arbitrary waveforms are expanded or condensed to exactly 4096 points and DDS techniques are used to perform the sweep.

Sweep Range: From 1mHz to 40MHz in one range. Phase continuous.

Sweep Trigger Source: The sweep may be free run or trigg er ed from the following sources:

Tone Switching

Capability provided for both standard and arbitrary waveforms. Arbitrary waveforms are expanded or condensed to exactly 4096 points and DDS techniques are used to allow instantaneous frequency switching.

± 360° settable with 0.1° resolution, subject t o waveform

Manually from keyboard. Externally from TRIG IN input or remot e

Trigger Repetition Rate: 0.005Hz to 100kHz internal; dc to 1MHz external.

Usable repetition rate and waveform freq uency depend on the t one

Source: Internal from keyboard or t r igger generator.

Tone Switching Modes:

FSK: The tone is output when the trigger signal goes true and the

Using 2 instruments with their outputs summed together it is possible to generate DTMF test signals.

Gated: The tone is output while the trigger signal is true and stopped, at the end of the cur r ent waveform c ycle, while the trig ger signal is false. The next tone is output when the trigger signal is true

Triggered: The tone is output when the trig ger signal goes true and the next tone is output, at the end of t he c ur r ent waveform cycle,

next tone is output, immediately, when the trigger signal goes true

Output Impedance:

50Ω

600Ω in Vpk−pk, Vrms or dBm.

Amplitude Accuracy:

2% ±1mV at 1kHz into 50Ω.

Amplitude Flatness:

± 0.2dB to 1MHz; ± 0.4dB to 40MHz

DC Offset Range:

±10V. DC off s et plus signal peak limited to ±10V from 50Ω.

DC Offset Accuracy:

Typically 3% ±10mV, unattenuated.

Resolution:

3 digits or 1mV for both Amplitude and DC Offset.

(all waveforms)

a pulse coincident with the first few points of an arbitr ar y waveform.

Burst Done:

Produces a pulse coincident with the last cycle of a burst.

gated signals.

oscilloscope or recorder. Can additionally output a sweep marker.

phase point.

point.

Frequency Range:

DC − 1MHz.

Signal Range:

Threshold level adjustable ±5V; maximum input ±10V.

Minimum Pulse Width:

50ns, for Trigger and Gate modes; 50us for Sweep mode.

Polarity:

Selectable as high/rising edge or low/falling edge.

Input Impedance:

10kΩ

Frequency Range:

DC – 100kHz.

SCM: Approximately ± 1Vpk for maximum output.

Input Impedance:

Typically 1 kΩ.

Trigger Generator

Internal source 0.005 Hz to 100kHz square wave adjustable in 10us steps. 3 digit resolution. Available for external use from the SYNC OUT socket.

OUTPUTS Main Output

Amplitude:

Sync Out

Multifunction output user definable or automatically selected to be any of the following: Waveform Sync:

Trigger: Selects the current trigger signal. Useful for synchronizing burst or

Sweep Sync: Outputs a trigger signal at t he s tart of sweep to synchronize an

Phase Lock Out: Used to phase lock two generators. Produces a pos it ive edge at t he 0°

Output Signal Level: Logic levels of <0.8V & >3V, except for Sweep Sync. Sweep Sync is a

5mV to 20Vp−p open circuit (2.5mV to 10Vp−p into 50Ω). Amplitude can be specified open circuit (hi Z) or into an assumed load of 50Ω or

A square wave with 50% duty cycle at the main waveform frequency, or

3-level waveform: low at start of sweep, high for the dur at ion of the last frequency step at end of s weep, with a narrow 1V pulse at the mar ker

INPUTS Trig In

Modulation In

Signal Range:

VCA: Approximately 1V pk−pk for 100% level change at m aximum output; maximum input ± 10V.

Frequency Range:

DC − 30 MHz .

±10V.

Input Impedance:

Typically 1kΩ.

level.

1V and 4V from 50Ω.

to synchronise (phase lock) two separate generators .

Maximum Input Voltage:

+5V, –1V.

RS232:

Variable Baud rate, 38400 Baud maximum. 9−pin D−connector.

IEEE−488:

Optional - Conforms with IEEE488.1 and IEEE488.2

USB

1.1

Display:

20 character x 4 row alphanumeric LCD.

numeric keys or by rotary control.

non-volatile memory.

Size:

3U (130mm) height; 212mm ( ½ −rack) width; 335mm long.

Weight:

4.1kg (9lb).

nominal; 60VA max. Installation Category II.

Operating Range:

+5°C to 40°C, 20−80% RH.

Storage Range:

−20°C to + 60°C.

Environmental:

Indoor use at altitudes up to 2000m, Pollution Degr ee 2.

Options:

19 inch rack mounting kit, GPIB remote control interface.

Safety:

Complies with EN61010−1.

EMC:

Complies with EN61326

Sum In

Signal Range:

Ref Clock In/Out

Set to Input: Input for an external 10MHz reference clock. TTL/ CMOS threshold

Set to Output: Buffered version of the internal 10MHz clock. Output levels nominally

Set to Phase Lock: Used together with SYNC OUT on a master and TRIG IN on a slave

INTERFACES

Full remote control facilities are available through the RS232, USB or G PI B interfaces.

GENERAL

Approximately 2 Vpk−pk input for 20Vpk −pk output; maximum input

Data Entry: Keyboard selection of mode, waveform etc.; value entry direct by

Stored Settings:

Power: 220-240V nominal 50/60Hz; 110-120V or 100V nominal 50/60/400Hz;

Up to 9 complete instrument set−ups may be stored and r ec alled from

nominal voltage adjustable internally; operating range ±10% of

incorrect operation may damage the instr um ent.

Safety

This generator is a Safet y Class I instr um ent according to IEC classification and has been designed to meet the requirem ents of EN61010−1 (Safety Requirements for Elect r ical Eq uipm ent for Measurement, Control and Laborator y Use). It is an Installation Category II instrument intended for operation from a normal single phase supply.

This instrument has been tested in accordanc e 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 r etain the inst rument in a safe condition.

This instrument has been designed f or 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° and −10°C without degradation of its safety. Do not operate while condensation is present.

Use of this instrument in a manner not spec ified by these instructions may impair the safety protection provided. Do not operate the instrum ent outside its rat ed supply voltages or environmental range.

WARNING! THIS INSTRUMENT MUST BE EARTHED

Any interruption of the mains earth conduct or inside or outside t he inst r um ent will make the instrument dangerous. Int entional 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, m aint enance 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.

If the instrument is clearly def ec t ive, 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.

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

This instrument uses a Lithium button c ell for non−volatile memory battery back−up; t ypic al life is 5 years. In the event of replacement becom ing nec essary, replace only with a cell of the cor r ect type, i.e. 3V Li/Mn0 in accordance with local regulations; do not cut open, incinerate, expose to t em per atures above 60°C or attempt to recharge.

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 t he inst r um ent and in this manual:−

20mm button cell type 2032. Exhausted cells must be disposed of car efully

Caution −refer to t he acc om panying documentation,

terminal connected to chassis ground.

mains supply OFF. mains supply ON.

alternating current.

Performance levels achieved are detailed in the user manual.

EC Declaration of Conf ormity

We Thurlby Thandar Instruments Ltd Glebe Road Huntingdon Cambridgeshire PE29 7DR England

declare that the

TG4001 40MHz DDS Function/Arbitrary Generator

meets the intent of the EMC Directive 2004/108/EC and the Low Voltage Directive 2006/95/EC. Compliance was demonstrated by conformance to the following specifications which have been listed in the Official Journal of the European Comm unit ies.

EMC

Emissions: a) EN61326-1 (2006) Radiated, Class A

b) EN61326-1 (2006) Conducted, Class B c) EN61326-1 (2006) Har m onics, referring to EN61000-3-2 (2006)

Immunity: EN61326-1 (2006) Immunity Table 1, referring to:

a) EN61000-4-2 (2009) Electrostatic Discharge b) EN61000-4-3 (2006) Electromagnetic Field c) EN61000-4-11 (2004) Voltage Interrupt d) EN61000-4-4 (2004) Fast Transient e) EN61000-4-5 (2006) Surge f) EN61000-4-6 (2009) Conduct ed RF

Safety EN61010-1 Installation Category II, Pollution Degree 2.

CHRIS W ILDING TECHNICAL DIRECTOR

2 January 2013

This instrument has been designed to meet the requirements of the EMC Directive 2004/108/EC. Compliance was demonstrated by meeting the test limits of t he following standards:

Emissions

EN61326-1 (2006) EMC product standard for Electrical Equipment for Measurement, Control and Laboratory Use. Test limits used were:

a) Radiated: Class A b) Conducted: Class B c) Harm onics: EN61000-3-2 (2006) Class A; the instrument is Class A by product category.

Immunity

EN61326-1 (2006) EMC product standard for Electrical Equipment for Measurement, Control and Laboratory Use.

Test met hods, limits and performance achieved are shown below (requirement shown in brackets):

a) EN61000-4-2 (2009) Electrostatic Discharge : 4kV air, 4kV contact, Performance A. b) EN61000-4-3 (2006) Electromagnetic Field:

EMC

3V/m, 80% AM at 1kHz, 80MHz – 1GHz: Performance A (A) and 1.4GHz to 2GHz: Performance A (A); 1V/m, 2.0GHz to 2.7GHz: Perf or m anc e A (A).

c) EN61000-4-11 (2004) Voltage Interrupt: ½ cycle and 1 cycle, 0%: Performance A (B);

d) EN61000-4-4 (2004) Fast Transient, 1kV peak (AC line), 0·5kV peak ( signal lines and RS232/GPIB ports), Perform ance A.

e) EN61000-4-5 (2006) Surge, 0·5kV (line t o line), 1kV (line to ground), Perform ance A. f) EN61000-4-6 (2009) Conducted RF, 3V, 80% AM at 1kHz (AC line only; signal

connections <3m, therefor e not tested), Performance A. According to EN61326-1 the definitions of performance criteria are:

Performance criterion A: ‘During test normal performance within the specificat ion limits.’ Performance criterion B: ‘During t est , temporary degradation, or loss of function or

performance which is self-recovering’. Performance criterion C: ‘During t est, temporary degradation, or loss of function or

performance which requires operator int er vention or s ystem r es et occ ur s.’

Cautions

To ensure continued com pliance with the EMC directive observe the following precautions: a) Connect generator to other equipment using only high quality, double-screened cables. b) After opening the case for any reason ens ur e t hat all signal and ground connections are

25 cycles, 70% and 250 cycles, 0%: Performance B (C).

remade correctly and that case screws are correc t ly refitted and tightened.

c) In the event of part replacement becoming necessary, only use components of an identical

type, see the Service Manual.

for 230V operation:

500 mA (T) 250V HRC

for 100V or 115V operation:

1A (T) 250V HRC

Mains Operating Voltage

Check that the instrument oper ating voltage marked on the rear panel is suitable for the local supply. Should it be neces sar y to change the operating voltage, proceed as follows:

1) Disconnect the inst r um ent from all voltage sources.

2) Remove the screws which retain the top cover and lift off the cover.

3) Change the t ransformer connections following the diagr am below.

4) Refit t he cover and t he s ecur e with the sam e s cr ews.

5) To comply with safety standard requirements the operating voltage marked on the rear panel must be changed to clearly show the new voltage setting.

6) Change the fuse to one of the correct r at ing, see below.

Installation

Fuse

for 230V operation connect the live (brown) wire to pin 15 for 115V operation connect the live (brown) wire to pin 14 for 100V operation connect the live (brown) wire to pin 13

7) Refit t he cover and t he s ecur e with the sam e s cr ews.

8) To comply with safety standard requirements the operating voltage marked on the rear panel must be changed to clearly show the new voltage setting.

9) Change the fuse to one of the correct r at ing, see below.

Ensure that the correct mains fuse is fitted for the set oper ating voltage. The correct mains fuse types are:

To replace the fuse, disconnect the mains lead from the inlet soc ket and withdraw the fuse drawer below the socket pins. Change the fuse and replace t he dr awer.

The use of makeshift fuses or the short−circuiting of the fuse holder is prohibited.

Brown

−

Mains Live

Blue

−

Mains Neutral

Green / Yellow

−

Mains Earth

Mains Lead

When a three c or e m ains 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” rack is available from the Manufacturers or their overseas agents.

Ventilation

The generator uses a small f an fitted to the rear panel. Tak e car e not to restrict the rear air inlet or the vents at the front (sides and underneath). In rack-mounted situat ions allow adequate space around the instrument and/or use a f an t r ay for forced cooling.

WARNING! THIS INSTRUMENT MUST BE EARTHED

first few points (addresses) of the waveform.

waveform is active at the main output and high at all other tim es.

external, manual and remote all produce a trigger sync.

marker pulse can be set to be output at any of the frequency steps.

coherent.

Front Panel Connec tions

MAIN OUT

This is the 50Ω output from the main generator. It will provide up to 20V peak−to−peak e.m.f. which will yield 10V peak−to−peak into a matched 50Ω load. It can tolerate a short circuit for 60 seconds.

Do not apply an external voltage to this output.

SYNC OUT

This is a TTL/CMOS level output which may be set to any of t he following signals from the

SYNC OUT screen.

Connections

waveform sync

Burst done

Trigger

Sweep sync

Phase lock

SYNC OUT logic levels are nominally 0V and 5V from typically 50Ω. SYNC OUT will withstand a short circuit.

Do not apply an external voltage to this output.

A sync marker phase coincident with the MAIN OUT waveform. For standard waveforms, (sine, cosine, haversines, squar e, triangle, sinx/x and ramp), the sync marker is a squarewave with a 1:1 duty cycle with the rising edge at the 0º phase point and the f alling edge at the 180º phase point. For arbitrary waveforms the sync marker is a positive pulse coincident with the

Provides a signal during Gate or Trigger modes which is low while the

Provides a positive going version of the actual trigg er signal; internal,

Goes low at the start of sweep and high for t he dur at ion of the last frequency step at the end of the sweep. In addition, a half-amplitude

Produces a positive edge coincident with the start of the curr ent waveform; this is used for phase locking instr um ents. This waveform may not appear

TRIG IN

This is the external input for Trigger, Gate, Sweep and Sequence operations. It is also the input used to synchronise the generator (as a slave) to anot her (which is the master).

Do not apply an external voltage exceeding ±10V.

internal clock when the external reference is applied.

output

The internal 10MHz clock is made available at the socket.

phase lock slave and the master is set to phase lock master.

Name

Description

TXD

Transmitted data from instrument

RXD

Received data to instrument

No internal connection

GND

Signal ground

6 − No internal connection

RXD2

Secondary received data

TXD2

Secondary transmitted data

GND

Signal ground

Rear Panel Connections

MODULATION IN

This is the input socket f or exter nal modulat ion.

Do not apply an external voltage exceeding ±10V.

SUM IN

This is the input socket f or exter nal sig nal sum m ing.

Do not apply an external voltage exceeding ±10V.

REF CLOCK IN/OUT

The function of the CLO CK IN/ O UT sock et is set from the ref clock i/o menu on the

UTILITY screen, see System Operations section. input

phase lock

As an output the logic levels are nominally 1V and 4V from typically 50Ω. CLO CK OUT will withstand a short−circuit. As an input the threshold is TTL/CMOS compatible.

Do not apply an external voltage exceeding + 5V or –1V.

MAIN OUT

This plugged panel position is provided for the user to fit a 50Ω BNC as an alternative to the front panel MAIN OUT socket where rear panel connections are required in a rack-mounted system. The front panel MAIN OUT connection must be carefully disconnected fr om the pcb and the pcb then rewired, using high quality 50Ω coax, to the new rear panel connector.

RS232

9−pin D−connector compatible with addressable RS232 use. The pin connections are shown below:

This is the default setting . The sock et bec om es an input for an external 10MHz reference clock. The system automatically switches over from the

When two or more generators are synchronised the slaves are set to

Do not apply external voltages exceeding + 5V or –1V to this signal connection.

Do not apply an external voltage to this output.

−

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

No internal Connection

remote menu on the UTILITY screen, see System Operations sec t ion.

GPIB (IEEE−488) OPTIONAL

The GPIB interface is not isolated; the GPIB signal grounds are connected to t he inst rument ground.

The implemented subsets are:

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

USB

The GPIB address is set fr om t he Operations section.

The USB port is connected to instrument ground. It accepts a standard USB cable. If USB has been selected as the current interf ac e t he Windows plug-and-play function should autom at ically recognise that the instrument has been c onnected.

remote menu on the UTILITY screen, see System

Initial Operation

This section is a general introduction to t he or ganisation of the instrument and is intended to be read before using the gener at or for the first time. Detailed operation is covered in later sections starting with Standard Waveform Operation.

In this manual front panel keys and sockets are s hown in capitals, e.g. OFFSET, SYNC OUT; all soft−key labels, entry fields and messages displayed on the LCD are shown in a different type−font, e.g.

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 waveform

RAM; if an error is encountered the message

firmware updated will be displayed, see the Warning s and Er r or Messages sec t ion.

Loading takes a few seconds, after which the status scr een is displayed, showing the g enerator parameters set to their def ault values, with the MAIN OUT output set off. Refer to the System Operations section for how to change t he power up settings to either those at power down or to any one of the stored settings. Recall the stat us s cr een at any time with the STATUS key; a second press returns the display to the previous screen.

General

WAVEFORM FUNCTIONS, sine.

system ram error, battery fault or

Change the basic generator parameters as des cr ibed in the Standard Waveform Oper at ion section and switch the output on with the MAIN OUT key; the ON lamp will light to show that the output is on.

Display Contrast

All parameter settings are displayed on the 20 character x 4 row backlit liquid cr ystal display (LCD). The contrast may vary a little with changes of ambient tem per at ur e or viewing angle but can be optimised for a particular environment by using the front panel contrast control. Insert a small screwdriver or trimmer tool through the adjustment aperture mark ed LCD and rotat e t he control for optimum contrast.

Keyboard

Pressing the front panel keys displays screens which list parameters or choices r elat ive to the key pressed. Selections are then made using the display soft−keys and numeric values are changed using the numeric keys or rotar y contr ol, see t he Pr inciples of Editing section.

The keys are grouped as follows:

• FUNCTION, FREQuency , AMPLitude, OFFSET and MODE keys display screens which permit their respective parameters to be edited either from the numeric keypad or using the rotary control/cursor keys.

• Numeric keys permit direct entry of a value for the parameter currently selected. Values are accepted in four formats: int eger (20), floating point (20· 0), exponential (2 EXP 1) and direct units selection (20Hz). For example, to set a new frequency of 50kHz press FREQ followed by 50000 ENTER or 5 EXP 4 ENTER or 50 kHz. ENTER or an appropriate units key confirms the numeric entry and changes the gener at or s et t ing to the new value. CE (Clear Entry) undoes a numeric entry digit by digit. ESCAPE returns a set ting being edited to its last value.

• MODULATION, SUM, TRIG IN and SYNC O UT call s c reens from which the parameters of those input/outputs can be set, including whether the port is on or off.

• SWEEP similarly calls screens from which all the parameters can be set and the function run.

• The MAIN OUT key simply switches the main output on or off.

• MAN TRIG is used for manual triggering (when TRIG IN is appropriately set) and for

synchronising two or more generators when suitably connected together.

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• UTILITY gives access to menus for a variety of functions such as remote control interface

set−up, power−up parameters, error message settings and store/rec all waveforms t o/from non−volatile memory.

• Eight soft−keys around the display are used to directly set or s elect paramet ers from the currently displayed menu; their operation is described in more detail in the next section.

• The STATUS key always returns the display to the default start−up screen which gives an overview of the generators status. Pressing STAT US ag ain returns the display to the previous screen.

Further explanations will be found in the detailed descriptions of the generat or’s operation.

Principles of Editing

Each screen called up by pressing a front panel key shows parameter value(s) and/or a list of choices. Parameter values can be edited by using the ROTARY CONTROL in combination with the left and right arrowed CURSOR keys, or by direct num er ic keyboard entry; choices are made using the soft−key associated with the screen it em to be selected. The examples which follow assume factory default set t ings.

A diamond beside a screen item indicates that it is selectable; hollow diamonds identify deselected items and filled diamonds denote selected items. For example, press MODE to get the screen shown below:

MODE:

continuous gated setup…◊ triggered setup…◊

The filled diamond indicates that the selected m ode is continuous. Gated or

Triggered modes are selected by pressing the associated soft−key which will make the

diamond beside that item filled and the diamond beside also illustrates how an ellipsis (three dots following the screen text) indicates that a further screen

follows when that item is selected. In the case of t he MODE screen illustr at ed, pressing the

continuous hollow. This screen

setup... soft−key on the bottom line brings up t he TRIGGER SETUP menu; note that

selecting this item does not change t he Some screen items are marked with a double−headed arr ow (a split diamond) when selected to

indicate that the item’s setting can be changed by fur ther presses of the soft−key, by pressing either cursor key or by using the rotary control. For example, pr es sing FILTER brings up the screen shown below.

FILTER SETUP

mode: auto

type: 40MHz eliptic

continuous/gated/triggered selection.

Repeated presses of the mode soft−k ey will toggle the m ode between its two possible settings

auto and manual. Similarly, when type is selected, repeated presses of the type

of soft−key (or cursor keys or use of the rotary control) will step the selection through all possible

settings of the filter type. In addition to their use in editing items identified by a double−headed arrow as described above,

the CURSOR keys and ROTARY CONTROL operate in two other modes. In screens with lists of items that can be selected ( i. e. it em s marked with a diamond) the cursor

keys and rotary control are used to scroll all items through the display if the list has more than three items; look, for example at the FUNCTION and UTILITY screens.

In screens where a parameter with a numeric value is displayed the cursor keys move the edit cursor (a flashing underline) thr ough the numeric field and the rotary control will increment or decrement the value; the step size is determined by the position of t he edit cursor within the numeric field.

Thus for FREQUENCY set to 1.000000000 MHz rotating the control will change the frequency in 1kHz steps. The display will auto−range up or down as the frequency is changed,

provided that autoranging permits the increm ent size to be maintained; this will in turn determine the lowest or highest setting that can be achieved by turning the control. In the example above, the lowest frequency that can be set by rotating the control is 1 kHz, shown on the display as

1.000000000 kHz.

This is the limit because to show a lower frequency the display would need to autorange below 1kHz to

xxx.xxxxxxx Hz in which the most significant digit repres ents 100Hz, i.e. the

1kHz increment would be lost. If, however, the starting frequency had been set to

1.000000000 MHz, i.e. a 100 Hz increment, the display would have autoranged at 1kHz to

900.0000000 Hz and could then be decremented down to 100.0000000 Hz without

losing the 100 Hz increment. Turning the control quickly will step numeric values in multiple increments.

Principles of Operation

The instrument operates in one of two different modes depending on the waveform selected. DDS mode is used for sine, cosine, haversine, triangle, s inx/x and ramp waveforms . Clock Synthesis mode (shown as vclk in the status menu) is used for sq uar e, pulse, pulse t rain, and arbitrary.

In both modes the waveform data is stored in RAM. As the RAM address is incremented the values are output sequentially to a Digital−to−Analogue Converter (DAC) which reconstructs the waveform as a series of voltages steps which are subsequently filter ed before being passed to the main output connector.

The main difference between DDS and Clock Synthesis modes is the way in which the addresses are generated for the RAM and the length of the waveform data.

Clock Synthesis Mode

In Clock Synthesis mode the addresses are always sequential (an increment of one) and the clock rate is adjusted by the user in the range 100MHz to 0·1Hz. The frequency of the waveform is clock frequency ÷ waveform length, thus allowing short waveforms to be played out at higher repetition rates than long waveforms, e. g. the maximum frequency of an 8 point waveform is 100e6÷8 or 12·5 MHz but a 1000 point waveform has a maximum frequency of 100e6÷1000 100kHz.

Arbitrary waveforms have a user defined length of 4 t o 65536 points. Squarewaves use a fixed length of 2 points and pulse and pulse train have their length defined by the user selected period value.

DDS Mode

In DDS mode (Direct Digital Synthesis) all waveforms are stored in RAM as 4096 points. The frequency of the output waveform is determined by the rate at which the RAM addresses are changed. The address changes are generat ed as follows:

The RAM contains the amplitude values of all the individual points of one cycle (360º) of the waveform; each sequential address change corresponds to a phase increment of the waveform of 360º/4096. Instead of using a counter to generate seq uent ial RAM addresses, a phase accumulator is used to increment the phase.

On each clock cycle the phase increment, which has been loaded into the phase increment register by the CPU, is added to the current result in the phase accumulator; the 12 most significant bits of the phase accum ulator drive the lower 12 RAM address lines, the upper 4 RAM address lines are held low. The output waveform frequency is now determined by the size of the phase increment at each clock. If each increment is the same size then the output frequency is constant; if it changes, t he out put frequency changes as in sweep mode.

The generator uses a 44 bit accumulat or and a 100 MHz clock f r equency; the frequency setting resolution is 0·1 mHz.

Only the 12 most significant bits of the phase accumulator are used to address the RAM. At a waveform frequency of F

CLK/4096 (~24·4kHz), the nat ur al frequency, the RAM address

increments at every clock. At all frequencies below this (i.e. at smaller phase increments) one or more addresses are output f or m or e than one clock period because the phase increment is not big enough to step the address at every clock . Similarly at frequencies above the natural frequency the larger phase incr em ent c auses s om e addr es ses to be skipped, giving the effect of the stored waveform being sampled; differ ent points will be sampled on successive cycles of the waveform.

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Function Generator Operation

This section deals with the use of the instrument as a function generator, i.e. generating sine, square, triangle, dc, ramp, haversine, cosine, havercosine and sinx/x waveforms. All but squarewave are generated by DDS which gives 10−digit frequency resolution; squarewave is generated by Clock Synthesis which results in 8−digit freq uency resolut ion. Refer to Principles of Operation in the previous section for a f uller explanation of the differences involved.

The

WAVEFORM FUNCTIONS screen lists all the waveforms that the instrument c an pr oduce

including pulse, pulse-train and arbitrary which are described in detail in their appropriate sections.

Much of the following descriptions of amplitude and offset control, as well as of Mode, Sweep, etc., in following sections, apply to arbitrary waveforms as well as standard f unction generator waveforms; for clarity, any differences of operation with arbitrary, pulse and pulse−train are described only in those sections.

Setting Generator Parameters

Waveform Selection

WAVEFORM FUNCTIONS

sine square triangle

Pressing the FUNCTION key gives the WAVEFORM FUNCTIONS screen which lists all the waveforms available; the rotary control or cursor keys can be used to scr oll the full list back and

forward through the display. The currently selected waveform (sine with the factory defaults setting) is indicated by the filled diamond; the select ion is changed by pressing the soft−key beside the required waveform.

Frequency

Pressing the FREQ key gives the SINE FREQUENCY screen. With freq selected as shown above, the frequency can be entered directly f r om the keyboard in integer, floating point

exponential or direct units format, e.g. 12·34 kHz can be entered as 12340, 12340·00, 1·234 exp 4 or 12.34 kHz etc. However, the display will always show the entry in the most appropriate engineering units, in this case 12·34000000 kHz.

With 123·4µs can be entered as ·0001234 or 123·4e−6; again the display will always show the entry in

the most appropriate engineering units. Squarewave, generated by Clock Synthesis has 8−digit r esolut ion for both frequency and period

entry but the editing method is the same as for DDS generated waveforms.

SINE FREQUENCY 10·00000000 kHz

freq period ◊

period selected instead of freq the f r equency can be set in terms of a period, e.g.

Turning the rotary control will increment or decrement the numeric value in steps determined by the position of the edit cursor (flashing underline); the cursor is moved with the left and rig ht arrowed cursor keys.

Note that the upper freq uenc y limits vary for t he different waveform types; refer to the Specifications section for details. Frequency setting for ar bit r ar y, pulse and pulse−train is explained in the relevant sections; all use Clock Synthesis mode.

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Amplitude

Pressing the AMPL key gives the AMPLITUDE screen. The waveform amplitude can be set in terms of peak−to−peak Volts (Vpp), r.m.s. Volts (Vrms) or

dBm (referenced to a 50Ω or 600Ω load). For Vpp and Vrms the level can be set assuming that the output is open−circuit ( is selected termination is always assumed and the

changed to displayed amplitude values for 600Ω termination tak e t his int o acc ount .

With the appr opr iat e form of the amplitude selected (indicated by the filled diamond) the amplitude can be entered directly from the keyboard in integer, floating point, exponential or direct units format, e.g. 250mV can be entered as ·250 or 250 exp −3, etc., However, the display will always show the entry in the most appropriate engineering units, in this case 250mV.

Alternate presses of the ± key will invert the MAIN OUT output; if DC OFFSET is non−zero, the signal is inverted about the same offset. The exception to this is if the amplitude is specified in dBm; since low level signals are specified in −dBm (0dBm = 1mW into 50Ω = 224mVrms) the

sign is interpreted as part of a new amplitude entr y and not as a command to invert the signal.

Note that for DC, sinx/x, pulse, pulse-tr ain and arbit r ar y amplitude can only be displayed and entered in the Vpp form; further limitations on pulse, pulse−train and arbitrary amplitude ar e discussed in the appropriate sections.

AMPLITUDE: +20·0 Vpp

Vpp Vrms ◊

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or load:600Ω); when dBm

load:hiZ setting is automatically

load:50Ω. Note that the actual generat or out put impedance is always 50Ω; the

DC Offset

Pressing the OFFSET key gives the DC OFFSET screen. The offset can be entered directly from the keyboard in integer, floating point, exponential or direct units format, e.g. 100mV can be entered as ·1 or 100 exp −3, etc. However, the display will always show the entry in the most

appropriate engineering units, in this case 100mV. During a new offset entry the ± key can be used at any time to set the offset negative; alternate presses toggle the sig n between + and −.

Turning the rotary control will increment or decrement the numeric value in steps determined by the position of the edit cursor ( flashing underline); the cursor is moved by the left and right arrowed cursor keys. Because DC offset can have negative values, the rotary contr ol can tak e the value below zero; although the display may autorange to a higher resolution if a step takes the value close to zero, the increment size is maintained correctly as the offset is stepped negative. For example, if the display shows

program = +205· mVdc with the cursor in the most significant dig it , the rotary control will decrement the offset in 100mV

steps as follows: program = +205· mVdc

program = +105· mVdc program = +5·00 mVdc

program = −95·0 mVdc program = −195· mVdc

DC OFFSET: program +0·00 mVdc (actual +0·00 mVdc)

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