Thurlby Thandar Instruments TG2000, TG1000 User Manual

THURLBY THANDAR INSTRUMENTS

TG1000 & TG2000

DDS Function Generators

INSTRUCTION MANUAL

	Table of Contents
Introduction	2
Specifications	3
Safety	6
EMC	8
Installation	9
Connections	10
Front Panel Connections	10
Rear Panel Connections	11
General	12
Initial Operation	12
Standard Waveform Operation	15
Setting Generator Parameters	15
AUX Output	18
Warnings and Error Messages	19
Sweep Operation	20
General	20
Setting Sweep Parameters	20
Gated Mode	25
Tone Mode	26
FSK	27
Modulation	28
System Operations from the Utility Menu	29
Calibration	31
Equipment Required	31
Calibration Procedure	31
Calibration Routine	32
Remote Calibration	33
Remote Operation	34
USB Interface	38
Remote Commands	39
Maintenance	42
Appendix 1. Warning and Error Messages	43
Appendix 2. Factory System Defaults	44

1

Introduction

This manual is for both the TG2000 and TG1000 function generators. The TG1000 has a maximum frequency of 10MHz and no remote control capability but is otherwise functionally the same as the TG2000 20MHz generator. Wherever there are differences in the specification or operation, the limits for the TG1000 are shown in square brackets [ ] after the TG2000 limits.

This 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 1mHz and 20MHz [10MHz] with a resolution of 6 digits and an accuracy better than 10ppm.

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 is related to that of the crystal master clock.

The DDS generator offers not only exceptional accuracy and stability but also 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 1mHz to 20MHz [10MHz].

Triangle waveforms can also be generated but with limitations as to the maximum usable frequency.

Variable symmetry/duty-cycle is available for squarewave and pulse waveforms.

Sweep

All waveforms can be swept from 0.2Hz to their maximum frequency in a single sweep at a rate variable between 50 milliseconds and 999 seconds. The sweep is fully phase continuous.

Sweep can be linear or logarithmic, single or continuous. the front panel, the trigger input, or the digital interfaces.

Single sweeps can be triggered from A sweep marker is provided.

AM

External Amplitude Modulation is available for all waveforms.

FSK and Tone modes

Frequency Shift Keying provides phase coherent switching between two selected frequencies; in Tone mode the output is stepped asynchronously through a user-defined list of up to 16 frequencies. In both modes the switching source can be the internal trigger generator, front panel, an external signal or a remote command.

Easy and convenient to use

All of the main generator parameters are clearly displayed together on a backlit LCD with 4 rows of 20 characters. Sub menus are used to set the parameters for each function.

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 numeric data entry with quasi-analogue adjustment when required.

Fully programmable via USB and Addressable RS-232 (TG2000 only)

The generator has both USB and RS-232 interfaces which can be used for remote control of all of the instrument functions.

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

2

Specifications

Specifications apply at 18°- 28°C after one hour warm-up, at maximum output into 50Ω. TG1000 limits, where different, are shown in square brackets [ ] after the TG2000 limits.

WAVEFORMS

Standard waveforms of sine, square, triangle, DC, positive pulse and negative pulse.

Sine

Range:	1mHz to 20MHz [10MHz]
Resolution:	1mHz or 6 digits
Accuracy:	10 ppm for 1 year; ± 1mHz below 0.2Hz
Temperature Stability:	Typically <1 ppm/ºC outside 18° to 28°C
Output Level:	2.5mV to 10Vp−p into 50Ω
Harmonic Distortion:	<0.3% THD to 20kHz (typically 0.1%)
	<–45dBc to 300kHz
	<−35dBc to 20MHz [10MHz] (typically <−40dBc)
Non−harmonic Spurii:	<–55dBc to 1MHz, <–55dBc + 6dB/octave 1MHz to 20MHz [10MHz]

Square

Range:	1mHz to 20MHz [10MHz]
Resolution:	1mHz or 6 digits
Symmetry Control:	20% to 80% (1% resolution) 1mHz to 20MHz [10MHz]
Accuracy:	10 ppm for 1 year; ± 1mHz below 0.2Hz
Output Level:	2.5mV to 10Vp−p into 50Ω
Rise and Fall Times:	<22ns
Aberrations:	<5% + 2mV

Triangle

Range:	1mHz to 1 MHz
Resolution:	1mHz or 6 digits
Accuracy:	10 ppm for 1 year; ± 1mHz below 0.2Hz
Output Level:	2.5mV to 10Vp−p into 50Ω
Linearity Error:	<0.5% to 100 kHz
Positive and Negative Pulses
Range:	1mHz to 20MHz [10MHz]
Resolution:	1mHz or 6 digits
Symmetry Control:	20% to 80% (1% resolution) 1mHz to 10MHz
Accuracy:	10 ppm for 1 year; ± 1mHz below 0.2Hz
Output Level:	1.25mV to 5Vp-p into 50Ω positive or negative only pulses, with respect
	to the DC Offset baseline.
Rise and Fall Times:	<22ns
Aberrations:	<5% + 2mV

OPERATING MODES

Continuous

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

3

Gated

Non-phase coherent gating - output carrier wave is on while Gate signal is high and off while low.

Carrier frequency:	From 1mHz to 20MHz [10MHz].
Carrier waveforms:	All
Trigger rep. rate:	DC to 100 kHz external; to 5kHz using internal trigger generator.
Gate signal source:	Manual (front panel MAN TRIG key), external signal (TRIG/GATE IN),
	internal gate generator or remote interface.

Sweep

Carrier Waveforms:	All
Sweep Mode:	Linear or logarithmic, single or continuous.
Sweep Width:	From 0.2Hz to 20MHz [10MHz] in one range. Phase continuous.
	Independent setting of the start and stop frequency.
Sweep Time:	50ms to 999s (3 digit resolution).
Marker:	Available from AUX output. Variable during sweep.
Sweep Trigger Source:	The sweep may be free run or triggered from any of the following sources:
	Manual (front panel MAN TRIG key), external from TRIG/GATE IN or from
	remote interface.

External Amplitude Modulation

Carrier Frequency:	From 1mHz to 20MHz [10MHz].
Carrier Waveforms:	All
Modulation Source:	VCA IN socket

Frequency Shift Keying (FSK)

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

Carrier frequency:	From 1Hz to 20MHz [10MHz].
Carrier waveforms:	All
Switch repetition rate:	DC to 5kHz (internal trigger) or DC to 1MHz (external trigger).

Switching signal source: Manual (front panel MAN TRIG key), internal trigger generator, external signal (TRIG/GATE IN) or remote interface.

Tone

The tone is output while the trigger signal is high and stopped while the trigger signal is low. The next tone is output when the trigger signal is high again.

Carrier Waveforms:	All
Frequency List:	Up to 16 frequencies from 1Hz to 20MHz [10MHz]
Switching Source:	Manual (front panel MAN TRIG key), internal trigger generator, external
	signal (TRIG/GATE IN) or remote interface.
Min Switching Time:	1ms per tone

OUTPUTS

Main Output

Output Impedance:

Amplitude:

Amplitude Accuracy:

Amplitude Flatness:

50Ω or 600Ω

5mV to 20V pk-pk open circuit, (2.5mV to 10V pk-pk into 50Ω/600Ω). Output can be specified as HiZ (open circuit value) or V (voltage into characteristic impedance) in pk-pk, r.m.s. or dBm.

±3% ±1mV at 1kHz into 50Ω/600Ω.

±0.2dB to 500kHz; ±2dB to 20MHz [±1dB to 10MHz].

4

DC Offset Range:	±10V. DC offset plus signal peak limited to ±10V from 50Ω/600Ω.
DC Offset Accuracy:	typically ±3% ±10mV, unattenuated.
Resolution:	3 digits for both Amplitude and DC Offset.
Pulse Aberrations:	<5% + 2mV.

Aux Out

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

Waveform Sync:	A square wave at the main waveform frequency. Symmetry is 50% for
	sine and triangle waves at MAIN OUT; for square waves and pulses
	symmetry is the same as that of the waveform at MAIN OUT.
Trigger:	Outputs a replica of the current trigger signal.
Sweep Sync:	Outputs a trigger signal at the start of sweep to synchronize an
	oscilloscope. Can additionally output a sweep marker.
Output Signal Level:	Output impedance 50Ω nominal. Logic levels of <0.8V & >3V, except
	for Sweep Sync. Sweep Sync is a 3-level waveform: low at start of
	sweep, high for the duration of the last frequency step at end of sweep,
	with a narrow 1V pulse at the marker point.

INPUTS

Ext Trig /Gate

Frequency Range:	DC - 1MHz for FSK; DC – 100kHz for Gate; DC – 2.5kHz for Tone and
	Sweep.
Signal Range:	Threshold nominally TTL level; maximum input ±10V.
Minimum Pulse Width:	100ns for Gate and FSK modes; 0.2ms for Sweep and Tone modes.
Input Impedance:	10kΩ
VCA In
Frequency Range:	DC - 100kHz.
Signal Range:	2.5V for 100% level change at maximum output.
Input Impedance:	typically 6kΩ.
INTERFACES (TG2000 only)
RS-232:	Variable Baud rate, 19200 Baud maximum. 9-pin D-connector.
	As well as operating in a conventional RS-232 mode the interface can
	be operated in addressable mode whereby up to 32 instruments can be
	addressed from one RS-232 port.
USB:	Standard USB hardware connection.
GENERAL
Display:	20 character x 4 row alphanumeric LCD.
Data Entry:	Keyboard selection of mode, waveform etc.; value entry direct by
	numeric keys or by rotary control.
Stored Settings:	Up to 9 complete instrument set-ups may be stored and recalled from
	non-volatile memory.
Size:	260(W) x 88(H) x 235(D)
Weight:	2kg. (4.5lb.)
Power:	110-120V AC or 220V-240V AC ±10%, 50/60Hz,
	adjustable internally; 35VA 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 Degree 2.
Safety & EMC:	Complies with EN61010-1 & EN61326.
	5

Safety

This 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° and −10°C without degradation of its safety. Do not operate 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! 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.

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.

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.

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:−

l

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.

6

EC Declaration of Conformity

We Thurlby Thandar Instruments Ltd

Glebe Road

Huntingdon

Cambridgeshire PE29 7DR

England

declare that the

TG1000 & TG2000 DDS Function Generators

meet 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 Communities.

EMC
Emissions:	a)	EN61326-1 (2006)		Radiated, Class B
	b) EN61326-1 (2006)			Conducted, Class B
	c) EN61326-1 (2006)			Harmonics, referring to EN61000-3-2 (2006)
Immunity:	EN61326-1 (2006) Immunity Table 1, referring to:
	a)	EN61000-4-2	(1995)		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	(2007)		Conducted RF

Performance levels achieved are detailed in the user manual.

Safety

EN61010-1 Installation Category II, Pollution Degree 2.

CHRIS WILDING TECHNICAL DIRECTOR

2 March 2010

7

EMC

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 the 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 B

b)Conducted: Class B

c)Harmonics: 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 methods, limits and performance achieved are shown below (requirement shown in brackets):

a)EN61000-4-2 (1995) Electrostatic Discharge : 4kV air, 4kV contact, Performance A (B).

b)EN61000-4-3 (2006) Electromagnetic Field:

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: Performance A (A).

c)EN61000-4-11 (2004) Voltage Interrupt: ½ cycle and 1 cycle, 0%: Performance A (B); 25 cycles, 70%: Performance A (C); 250 cycles, 0%: Performance B (C).

d)EN61000-4-4 (2004) Fast Transient, 1kV peak (AC line only; signal connections <3m, therefore not tested), Performance A (B).

e)EN61000-4-5 (2006) Surge, 0·5kV (line to line), 1kV (line to ground), Performance A (B).

f)EN61000-4-6 (2007) Conducted RF, 3V, 80% AM at 1kHz (AC line only; signal connections <3m, therefore not tested), Performance A (A).

According to EN61326 the definitions of performance criteria are:

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.’

Cautions

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. For the purposes of EMC testing it is assumed that signal connections from the instrument will be <3m and therefore immunity tests for signal lines (Fast Transient and Conducted RF) have been omitted.

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, see the Service Manual.

8

Installation

Mains Operating Voltage

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

1)Disconnect the instrument from all voltage sources.

2)Unclip the front bezel by gently pulling the centre of each long edge up and forward.

The case halves are held together by 4 plastic push-rivets. Use the blade of a small screwdriver in the slot beside each rivet to first ease out the rivet head and then fully remove the rivet body. Separate the case halves. Visit www.tti-test.com for further details.

3)Remove the screws securing the pcb to the case lower and lift out the pcb with front and rear panels attached; lift one side of the pcb at a time, with the case pcb clips on that side pulled clear of the pcb edge.

4)Change the voltage settings by changing the soldered links beside the transformer:

For 230V operation fit link LK2 only

For 115V operation fit links LK1 and LK3 only

5)Reassemble in the reverse order.

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

7)Change the fuse to suit the new operating voltage, see below.

Fuse

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

for 230V operation:	250 mA (T) 250V HRC
for 100V or 115V operation:	500 mA (T) 250V HRC

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

Mains Lead

Connect the instrument to the AC supply using the mains lead provided. Should a mains plug be required for a different mains outlet socket, a suitably rated and approved mains lead set should be used which is fitted with the required wall plug and an IEC60320 C13 connector for the instrument end. To determine the minimum current rating of the lead-set for the intended AC supply, refer to the power rating information on the equipment or in the Specification.

WARNING! 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.

9

Connections

Front Panel Connections

MAIN OUT

This is the output from the main generator; output source impedance can be set to 50Ω or 600Ω. It will provide up to 20V peak−to−peak e.m.f. which will yield 10V peak-to-peak into a matched load. To maintain waveform integrity only 50Ω cable should be used and the receiving end should be terminated with a 50Ω load. It can tolerate a short circuit for 60 seconds.

Do not apply external voltages to these outputs.

AUX OUT

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

AUX OUT screen.
waveform sync	A sync signal phase coincident with the MAIN OUT waveform. For sine
	and triangle waves the sync waveform rising edge is at the 0º phase
	point of MAIN OUT and the falling edge is at the 180º phase point. For
	square waves and pulses both phase and symmetry are coincident with
	MAIN OUT.
Trigger	Provides a replica version of the actual trigger signal; internal, external,
	manual and remote all produce a trigger sync.
Sweep sync	Goes low at the start of sweep and high at the last frequency step of
	the sweep. In addition, a 1/4-amplitude marker pulse can be output at
	a specified marker frequency.

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

Do not apply external voltage to this output.

TRIG/GATE IN

This is the external input for Trigger, Gate and Sweep operations.

Do not apply external voltages exceeding ±10V.

VCA IN

This is the input socket for external amplitude modulation.

Do not apply external voltages exceeding ±10V.

10

Rear Panel Connections (TG2000 only)

RS-232

9−pin D−connector compatible with addressable RS-232 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 RS-232 interface with XON/XOFF handshaking. Pins 7, 8 and 9 are additionally used when the instrument is used in addressable RS-232 mode. Signal grounds are connected to instrument ground. The RS-232 address is set from the remote menu on the UTILITY screen, see System Operations section.

USB

The USB port accepts a standard USB cable. The Windows plug-and-play functions should automatically recognise that the instrument has been connected.

11

General

Initial Operation

This section is a general introduction to the organisation of the instrument and is intended to be read before using the generator 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 shown in capitals, e.g. STATUS, AUX OUT; all soft−key labels, entry fields and messages displayed on the LCD are shown in a different type−font, e.g. WAVEFORM, sine.

DDS Principles

In this instrument waveforms are generated by Direct Digital Synthesis (DDS). A phase accumulator is incremented at a rate proportional to the required output frequency. The most significant 12 bits of the accumulator are used to address a look-up table ROM that converts the phase information into sinewave amplitude data; this data is then passed to a 10-bit Digital-to- Analogue Converter (DAC) which produces the output waveform. For triangle waves the ROM look-up table is by-passed and the phase accumulator output is passed directly to the DAC.

At low frequencies all 4096 points in the output wave are stepped through, but as the frequency increases points are progressively missed out. Sinewaves and triangles are subsequently filtered to smooth the steps in the DAC output; this technique ensures good sinewave purity up to the maximum frequency of the generator but the practical limit to which excellent triangle linearity is maintained is only about 100kHz. Squarewaves and pulses are derived from the sinewave using a variable threshold comparator; this permits symmetry control of these waveforms across the whole instrument frequency range.

The major advantages of DDS over conventional analogue generation are:

•Frequency accuracy and stability is that of the crystal oscillator.

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

•Low phase noise and distortion.

•Very wide frequency sweeps are possible.

•Fast phase continuous frequency switching.

•In addition, being a digital technique, it is easier to make every parameter programmable from the keyboard, or remotely via the USB or RS-232 interfaces.

Switching On

Switch on the generator using the ON/OFF switch on the rear panel. To fully disconnect from the AC supply unplug the mains cord from the back of the instrument or switch off at the AC supply outlet; make sure that the means of disconnection is readily accessible. Disconnect from the AC supply when not in use.

At power up the generator displays the installed software revision and conducts a self-test. Power-on self-test takes a few seconds, after which the status screen is displayed, showing the generator parameters set to their default values, with the MAIN OUT output set off. Refer to the System Operations section for how to change the power up settings to either those at power down or to any one of the stored settings. Recall the status screen at any time with the STATUS key; a second press returns the display to the previous screen.

Change the basic generator parameters as described in the Standard Waveform Operation section and switch the output on with the ON key; the lamp above the key will light to show that output is on.

12

Display Contrast

All parameter settings are displayed on the 20 character x 4 row backlit liquid crystal display (LCD). The contrast may vary a little with changes of ambient temperature 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 marked LCD and rotate the control for optimum contrast.

Keyboard

Pressing the MENU key calls the top-level menu from which all functions can be accessed. Selections are made from this menu using the display soft-keys and numeric values are then changed using the numeric keys or rotary control, see the Principles of Editing section.

The keys are as follows:

•MENU calls the top-level menu screen from which the main functions can be directly selected. These are WAVEFORM, FREQUENCY, AMPLITUDE, DC OFFSET, SYMMETRY, MODE, UTILITY and AUX OUT. Pressing the associated soft-key of any of these functions calls a further screen which permits the parameters of that function to be edited either from the numeric keypad or by using the rotary control/cursor keys.

•Numeric/Unit keys permit direct entry of a value for the parameter currently selected. Thus, having selected the FREQUENCY screen (by pressing the FREQUENCY soft-key on the MENU screen), a new frequency of 100kHz, for example, is set by pressing 1, 0, 0, kHz.

CE (Clear Entry) undoes a numeric entry digit by digit. ESCAPE returns a setting being edited to its last value.

•Eight soft-keys around the display are used to directly set or select parameters 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 generator’s status. Pressing STATUS again returns the display to the previous screen.

Further explanations will be found in the detailed descriptions of the generator’s operation in the sections that follow.

Status Display

After the messages at switch-on, or at any time the STATUS key is pressed, the Status display is shown. With the generator set to the factory defaults (Appendix 2), the display will be:

WAVE:sine

FREQ:10·0000kHz CONT

AMPL:+4·00Vpp

DC:+0·00Vdc (+0·00V)

This display gives an overview of the status of the main generator parameters. If a waveform is selected for which symmetry can be set (see Specification) the additional field of SYMmetry is shown to the right of the waveform type, see example below:

WAVE:square SYM:35%

FREQ:10·0000kHz CONT

AMPL:+4·00V

DC:+0·00Vdc (+0·00V)

For convenience, the WAVEFORM, FREQUENCY, AMPLITUDE, DC OFFSET, SYMMETRY and MODE screens can be directly selected from the Status display, (i.e. without having to first return to the main MENU) by pressing the appropriate soft-key beside WAVE, FREQ, AMPL, etc.

13