Thurlby Thandar Instruments TG550 User Manual

TG550

Precision 5MHz Function Generator

INSTRUCTION MANUAL

Table of Contents

Introduction 2 Specification 3 EMC 7 Safety 8 Installation 9 Operation 10 Calibration and Maintenance 13 Instructions en Francais Sécurité 14 Installation 15 Fonctionnement 16 Calibrage et maintenance 20 Bedienungsanleitung auf Deutsch Sicherheit 21 Installation 22 Betrieb 23 Kalibrierung und Wartung 27 Istruzioni in Italiano Sicurezza 28 Installazione 29 Funzionamento 30 Calibrazione e Manutenzione 34 Instrucciones en Español Seguridad 35 Instalación 36 Funcionamiento 37 Calibrado y Mantenimiento 41

Introduction

The TG550 is a precision 5MHz function generator with waveforms of sine, t r iangle, ramp. pulse and DC from a variable amplitude 50Ω or 600Ω output. A TTL/CMOS auxiliary output is also provided.

The frequency range is 0· 005Hz to 5MHz selected by a seven decade range multiplier and calibrated vernier. Both the frequency vernier and the sweep input can give 1000:1 frequency change within a selected range. Frequency can be locked t o a c r ystal reference to give superior frequency stability. A 10:1 symmetry range per mits ramp and pulse waveforms to be produced.

The generator output level is 20Vpk-pk maximum from a 50/600Ω source. The level is set via a switched attenuator plus vernier with a total range of >80dB. DC offs et is vernier adjustable over a ±10V range with centre detent for 0V. Waveform quality is good at all frequenc ies and sig nal levels.

The TG550 also has internal LIN/LOG sweep with sweep output. Amplitude modulation of up to 100% is possible using the internal 400Hz oscillator or an external source.

The large liquid crystal display shows frequency and amplitude simultaneously. Good resolution and a fast display update rate are maintained at all frequencies. The display can also be used as an external 20MHz frequency meter with up to 7-digit resolution.

Additional display annunciators indicate generator status when sweep, AM, etc. are in use.

coarse and fine verniers.

Vernier Range:

1000:1 on each range.

of range full scale (unspecified with Symmetry on).

displayed value ± 0·01%.

5MHz range.

Amplitude Flatness:

± 0·2dB to 200kHz; ± 2dB to 5MHz.

Linearity:

Rise and Fall Times:

<45ns.

Mark-Space Ratio:

1:1 ±1% to 100kHz.

Range:

±10V (unterminated).

frequency divided by 10 when Symmetry is selected.

External: linear.

Sweep Width:

Up to 1000:1 within each range.

Sweep Rate:

Internal sweep rate adjustable from typically 20ms to 20s.

External Sweep:

By signal applied by SWEEP IN/OUT socket.

Specification

Specifications apply at 18º - 28º after one hour warm-up, at maximum output int o 50Ω.

FREQUENCY

Frequency Range: 0·005Hz to 5MHz in 7 overlapping decade ranges with adjustment by

Frequency Display: Auto-ranging reciprocal measurement giving 4-digit resolution down to

10Hz (to 1Hz on the 5Hz range); resolution is fixed at 0·01Hz below 10Hz (0·001Hz below 1Hz on the 5Hz range).

Accuracy is ± 1 digit 5MHz to 2·1Hz (to 0·21Hz, Symmetry off, or to 0·42Hz, Symmetry on, on the 5Hz range); below this the accuracy is ± 1%

Frequency Locking: With vernier setting between 10% and 100% of range maximum,

frequency can be locked to the cr ystal reference to maintain it at the

WAVEFORMS

Waveform specifications apply f or t he top decade of each frequency rang e.

SINE

Distortion: Less than 0·5% on 500Hz, 5kHz and 50kHz ranges; less than 1% on 5Hz,

50Hz and 500kHz ranges; all harmonics >25dB below fundamental on

TRIANGLE

Better than 99% to 200kHz.

SQUAREWAVE

SYMMETRY

Symmetry Range: Variable typically between 1:9 and 9:1 (on top decade of each range),

MODULATION MODES

Modulation can be used with all waveforms and at any frequency.

Sweep

Sweep Mode: Internal: linear or logarithmic; s weep Start and Stop frequencies

displayed at a press of a button.

Modulation Depth:

Variable 0 to 100% typical.

Modulation Frequency:

400Hz internal. DC to 100kHz external.

External Modulation:

By signal applied to COUNT/AM IN socket.

Output Impedance:

50Ω.

range.

Attenuator:

0, –20, – 40 or – 60dB.

plus waveform attenuated proportionally by the attenuator.

Output Characteristics:

Frequency, symmetry and phase the same as main outputs.

loads.

Input Impedance:

10kΩ.

Input Sensitivity:

0 to 3V for 1000:1 sweep.

Voltage:

±10V.

Sweep Linearity:

Better than 1%

Sweep Voltage:

0·1V/µs.

Input Impedance:

40kΩ.

Input Sensitivity:

Approximately 2V peak-peak for 100% modulat ion.

Voltage:

Amplitude Modulation

OUTPUTS

50Ω Main Out

Amplitude:

DC Offset Range:

2mV to 20V peak-peak open circuit (1m V t o 10V peak-peak into 50Ω) in four switch-selectable ranges with 20dB vernier control within each

±10V. DC offs et plus signal peak limited to ±10V (±5V into 50Ω); CLIP shows in display when offset + signal peak exceeds ±10V. DC offset

600Ω Main Out

Alternative output socket providing the same signal as the 50Ω Main Out but from 600Ω. The 50Ω and 600Ω sockets ar e not independent .

Aux Out

Output Level: 0 to 5V TTL/CMOS logic levels capable of driving 2 standard TTL

Sweep Out

When internal sweep is selected the sweep signal is available as a 0 to 3V ramp from 600Ω.

INPUTS

Sweep In

The SWEEP IN/OUT socket is set to Sweep In when EXT SWEEP is selected.

Maximum Allowable Input

Maximum Slew Rate of

AM In

The AM/COUNT IN socket is set to AM input when EXT AM is selected.

Maximum Allowable Input

±10V.

Input Impedance:

1MΩ//25pF.

Input Sensitivity:

50mVrms (sinewave) typical; 80mVrms max.

1Vrms above 1MHz.

± 1% of range f ull scale (unspec ified with Symmetry on).

±5% of range f ull scale.

Display corrected for attenuator setting.

Frequency Range:

5Hz to 20MHz, fully autoranging.

Input Sensitivity:

50mVrms (sinewave).

Measurement Time:

Selectable 0·5s or 5s.

Resolution:

6 digits in 0·5s; 7 digits in 5s.

Accuracy:

±1 digit ± timebase accuracy.

ppm/ºC.

adjustment. Installation Category II.

Power Consumption:

25VA max.

Operating Range:

+5°C to +40°C, 20% to 80% RH.

Storage Range:

-10°C to +65°C

Environmental:

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

feet.

Weight:

1.9kg (4.2lb).

Safety:

Complies with EN61010-1.

EMC:

Complies with EN61326.

Count In

The AM/COUNT IN socket is set to external freq uenc y measur em ent when EXT COUNT is selected.

Maximum Allowable Input Voltage:

50Vdc/50Vrms to 400Hz with respect to ground

, reducing to

DISPLAY FUNCTIONS

The LCD shows generator frequenc y simultaneously with output amplitude/offset, together with various status annunciators. Alternatively, it is the external freq uency measur em ent display.

Internal Measurement Accur acy

Frequency: Auto-ranging reciprocal measurement giving 4-digit resolution down

to 10Hz (to 1Hz on the 5Hz range); resolution is fixed at 0·01Hz below 10Hz (0·001Hz below 1Hz on the 5Hz range).

Accuracy is ± 1 digit 5MHz to 2·1Hz (to 0·21Hz, Symmetry off, or to 0·42Hz, Symmetry on, on the 5Hz range); below this the accuracy is

Amplitude: Display shows peak-to-peak amplitude or rms value. Display

corrected for attenuator setting. 3-digit res olution, ac curacy typically

DC Offset: 3-digit resolution; accuracy typically ±2% setting ± 1 dig it .

External Frequency Measurement

Timebase Accuracy: ±10ppm initial error; ± 5 ppm/year ag eing r ate; typically less than 0·5

GENERAL

POWER REQUIREMENTS

AC Input Voltage: 220V AC-240V AC or 110V AC-120V AC ±10%, 50/60Hz, by internal

Size: 260 (W) x 88 (H) x 235 (D) mm (10.2 x 3.4 x 9.2") excluding handle and

Performance levels achieved are detailed in the user manual.

EC Declaration of Conformity

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

declare that the

TG550 Precision 5MHz Function 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 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 (2009) Electrostatic Discharge b) EN61000-4-3 (2006) Electromagnetic Field c) EN61000-4-11 (2004) Voltage Interr upt d) EN61000-4-4 (2004) Fast Transient e) EN61000-4-5 (2006) Surge f) EN61000-4-6 (2009) Conducted 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 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 per formance achieved are shown below (requirement shown in brackets):

a) EN61000-4-2 (2009) Electros tatic Dischar ge : 4kV air, 4kV contact, Performance A (B) .

EMC

b) EN61000-4-3 (2006) Electr omagnetic Field:

3V/m, 80% AM at 1kHz, 80MHz – 1GHz: Performance B 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%: Per formance A (B);

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

d) EN61000-4-4 (2004) Fast Transient, 1kV peak ( AC line), 0·5kV peak (signal connections), Performance A (B).

e) EN61000-4-5 (2006) Surg e, 0·5kV (line to line), 1kV (line to gr ound), Performance A ( B) . f) EN61000-4-6 (2009) Conducted RF, 3V, 80% AM at 1kHz (AC line only; signal

connections <3m, therefor e not tested), Performance B



Note: If the generat or is subjected to sufficiently large m odulated RF fields (radiated or

conducted) some minor modulation of t he out put waveform may be visible at certain frequencies up to about 100MHz. However, possible degradation will be small and infrequent and not deemed to be a problem in practice. In all other res pect s t he inst rument will operate normally (Performance A) in fields up t o 3V/ m .

According to EN61326-1 the definitions of performance criteria are:

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

performance which is self-recovering’.



(A) and 1.4GHz to 2GHz:



(A).

Performance criterion C: ‘During t est, temporary degradation, or loss of function or performance which requires operator int er vention or s ystem r eset occurs.’

Cautions

To ensure continued compliance with the EMC directive observe the following precautions: a) Connect t he generator to other equipment using only high quality, double−screened cables. b) Aft er opening the case for any reason ensure that all signal and g round connections are

remade correctly.

c) In the event of part replacement becoming nec essary, only use components of an ident ical

type, see the Service Manual.

may damage the instrument.

terminal connected to chassis ground.

alternating current.

Safety

This instrument is Safety Class I accor ding 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 oper ation 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 saf e oper at ion and t o 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°C 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 for replacement. The use of makeshift fuses and the short-circuiting of fuse holders is prohibited.

Do not wet the instrument when cleaning it. The following symbols are used on the instrument and in this m anual:-

Caution - refer to the accompanying documentation, incorrect operation

Mains Operating Voltage

The operating voltage of the instr um ent is shown on the rear panel. Should it be necessary to change the operating voltage from 230V t o 115V or vice-versa, proceed as follows:

1. Disconnect the instrument fr om all voltage sources.

2. Remove the 4 screws which hold the upper and lower case halves together and lift off the case lower.

3. Remove the 6 screws securing the main pcb to the case upper and lift the pcb free, complete with front and rear panels.

4. Change the appropriate zero-ohm links beside the transformer on the pcb:

Link LK2 only for 230V operation Link LK1 and LK3 only for 115V operation

5. Refit the pcb to the case upper, ensuring all connections (especially safety earth) ar e remade as before, and refit the case lower.

6. To comply with safety standard requirem ents t he oper ating voltage marked on the rear panel must be changed to clearly show the new voltage setting.

Installation

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

Fuse

The correct time-lag fuse must be fitted for the selected operating voltage. For 230V operation use 125mA (T) 250V HBC. For 115V oper at ion use 250mA (T) 250V HBC. Make sure that only fuses with the required rated cur rent and of the specified type are used for

replacement. The use of makeshift fuses and the short-circuiting of fuse holders are prohibited.

Mains Lead

When a three c or e m ains lead with bare ends is pr ovided it should be connected as follows:

Brown - Mains live Blue - Mains Neutral Green/Yellow - Earth

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.

WARNING! THIS INSTRUMENT MUST BE EARTHED

Switching On

Switch on the generator using the ON/O FF switch on the r ear 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.

Ensure that the push-button switches in the SWEEP and AM/EX TERNAL COUNTER sections of the control panel are all set to the position, i.e. set t he generator to its normal, unmodulated, running mode. The display will show the frequency and peak-to-peak out put amplitude with appropriate range annunciators.

Frequency

Frequency Setting

Frequency is set by pressing the appropriate FREQUENCY RANGE push button and rotating the calibrated FREQUENCY vernier; precise adjustments can be made using the FINE control. The vernier controls provide a 1000:1 frequency change within each rang e. The auto-ranging meter makes reciprocal freq uenc y measur em ents down to 2·1Hz (to 0· 21Hz on the 5Hz range) ; the display update rate in this mode is 130ms or 1 waveform period, whichever is the longer. Below these frequencies a f ast measurement update rate is maintained by changing the measurement method but accuracy is reduced, see Specification.

Operation

When SYMMETRY is switched ON the SYMMETRY control can be used to vary the duty cycle from 1:10 to 10:1 to pr oduce s awtooth and variable pulse-width waveforms. Optimum performance of the SYMMETRY cont r ol is achieved on the top decade of each frequency range. When SYMMETRY is selected SYM shows in the display and the generator frequency is divided by 10; the display shows the correct frequency. The changeover in frequency measurement method now happens at 0·21Hz on the 50Hz range and 0·42Hz on the 5Hz range.

Frequency Locking

The set frequency can be maintained precisely by using the FREQUENCY LOCK feature. Press the LOCK button once to light the READY lamp. With READY lit set the required frequency in the usual way, ensuring that the FREQUENCY RANGE has been selected such that the FREQUENCY vernier control is within its top decade, i.e. between 0·5 and 5.

Press LOCK a second time to activate frequency locking; the LOCKED lamp will light to show that frequency locking is oper at ional. Fr equency locking is disabled by pressing LOCK again (the LOCKED lamp goes off) or by changing the frequency using the vernier or fr equency range switches.

Frequency Locking employs a ‘measure-and-cor r ect’ technique; at low frequencies the time between measurements is long (2s at 0·5Hz) and frequency stability may therefore be poorer.

Warning is given if fr equency lock is about to be lost by flashing the LOCKED lamp; t his m ay occur with extreme variations of time and temperat ur e which may cause the natural frequency of the generator to drift outside the frequency locking control range.

Waveform

The output waveform shape is selected by depressing one of the three function buttons t o give sine, square or triangle. With all three switches out (acc om plished by half -depressing any one) the output will be a DC level only; this is useful as it permits input threshold testing of a cir cuit without having to connect up an external DC supply.

Amplitude

The amplitude of the MAIN OUT outputs is set by the AMPLITUDE control and the ATTENUATOR switches. Maximum output is 20 volts peak-to-peak open-cir cuit , 10 volts peak-topeak when terminated with the outputs characteristic impedance.

The AMPLITUDE control has greater t han 20dB range; the ATTENUATOR switches permit selection of up to -60dB attenuation (bot h s witches press ed t ogether). Used together t hes e controls provide a range of 20V peak-to-peak down to 2mV peak-to-peak, or 10V peak-to-peak down to 1mV peak-to-peak into the output’s characteristic impedanc e.

Still greater attenuation of the 50Ω MAIN OUT can be achieved by using standard 50Ω BNC attenuators. To maintain waveform integrity only 50Ω cable should be used and the receiving end should be terminated with a 50Ω load.

The MAIN OUT outputs will withstand a short circuit for a period of 10 minutes at maximum output and greater periods at lower output levels. However, damage will occur if an external voltage is connected to the output sockets.

The 50Ω and 600Ω outputs ar e not independent ; terminating one will affect the amplitude of the other.

The amplitude is displayed on the right-hand side of t he LCD; pressing the PK-PK/RMS button beside the display will alternate the reading between peak-to-peak volts (Vp-p) and r.m.s. volts (Vrms). The readout is correctly adjusted for att enuator setting and waveform shape.

The display shows open circuit voltage; the actual voltage at the socket will be half the displayed value when the output is terminated with its characteristic impedance.

DC Offset

The DC OFFSET control has a range of ±10 volts fr om 50Ω/600Ω in all output modes; the c ont r ol has a centre detent for 0 volts. DC offset plus signal peak is limited to ±10V (±5V into the characteristic output impedance); CLI P shows in the display when this limit is exceeded. DC offset plus waveform is attenuated proportionally by the ATTENUATOR switches.

The DC offset can be displayed in place of the output amplitude by pressing the OFFSET button beside the display. The display shows open circuit voltage offset; the actual voltage at the socket will be half the displayed value when the output is terminated with its characteristic impedance.

Auxiliary Output

The AUX OUT output provides a fixed 0 to 5V TTL/CMOS pulse output at the same frequency, symmetry and phase as the MAIN OUT outputs and is capable of driving 2 standard TTL loads.

Internal Sweep

With INT SWEEP selected the output of the internal sweep generat or is summed with the FREQUENCY vernier. Select LIN or LO G s weep mode; t he annunc iators LIN-SWP or SWP-LOG will show in the display accordingly.

Frequency Selection

Using the FREQUENCY RANGE switches select the lowest range within which the upper sweep limit can be set; in this way the best setting resolution and the widest sweep range can be realised.

Sweep Limits

Turn the STOP control to minimum (fully-anticlockwise). Hold the SET START button and set the START (lowest) freq uency on the display using the FREQ UENCY vernier; the START frequency must be set first. Now release the SET START button, hold in the SET STOP button and set the STOP (highest) frequency on the display using the STOP control; release the SET STOP button. Note that both the FREQUENCY vernier and the STOP control have a log characteristic when LOG mode is selected.

The sweep limits can be checked at any time by depressing the SET START or SET STOP.

Sweep Rate

The generator sweeps both up and down at the speed set by the RATE control, i.e. it does not reset rapidly after the upward sweep. This has the advantage that the suitability of the selected sweep time can be continuously monitored.

Sweep Out

When INT SWEEP is selected the SWEEP IN/OUT socket becomes an out put providing a 0V to 3V ramp from 600Ω im pedance to drive the X-input of an oscilloscope or chart r ecor der. Terminating this output with a resistor will reduce the output amplitude. Terminating with 600Ω will halve the output giving 0V to 3V.

Holding in the SET STOP button holds the ramp at the maximum and can therefore be used t o set full scale on the oscilloscope or chart recor der.

Note that when SWEEP IN/OUT is used as an output to drive the X -input of an oscilloscope, the oscilloscope should be set to DC coupling and not AC coupling which will cause a double image at slow sweep speeds.

External Sweep

When EXT SWEEP is selected the SWEEP IN/OUT socket becomes an input. The generator frequency can be swept, DC programmed or modulated by a suitable control voltage applied to this input. The instrument sums the SWEEP IN voltage with the internal control voltage derived from the FREQUENCY vernier to determine the operating frequency; the display shows the resultant frequency.

A positive voltage increases the frequency; f or frequency control with positive-going DC inputs the vernier should therefore be set to t he lower frequency limit of the range t o be swept. For example, a 0V to +3V signal will sweep the generator 3 decades up from range minimum, set by the vernier, to range maximum.

Similarly, a negative voltage decreases the frequency and for negative-going DC inputs the vernier should be set to the upper freq uency limit of the range to be swept. For example, a 0V to

-3V signal will sweep the generator 3 decades down from range maximum, s et by t he vernier, to range minimum.

To use a sweep signal which is symmetrical about ground, t he vernier should be set to give a frequency at approximately the centre of the band to be swept.

In external sweep mode the LIN/LOG selection is inoperative, i.e. t he FRE QUENCY vernier is always operating linearly, as marked.

Note: Non-linear operation may result when the sweep input voltage is excessive; that is, when the attempted generator frequency exceeds the range limits.

Amplitude Modulation

Depressing the AM ON/OFF button selects AM. The depth of m odulat ion can be adj usted over a 0% to 100% range using the modulation DEPTH cont rol. When AM is selected the output amplitude will drop to 50% at 0% modulation.

With the AM INT/EXT button in the INT (internal) position, the modulation sour c e is an inter nal 400Hz sinewave oscillator. The INT-AM annunciator is displayed.

With the AM INT/EXT button in the EXT (external) position, and the EXT COUNT/EX T AM button in the EXT AM position, exter nal AM modulation is possible via the AM/COUNT IN socket; the AM-EXT annunciator is displayed. The modulating signal applied should have no DC offset or should be AC coupled. A 2V peak-to-peak signal gives approximately 100% modulation with the modulation control at maximum. Modulating the generator with a squarewave gives step changes in the output amplitude which are suitable for testing signal compressors and automatic gain controlled circuits.

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