Wavetek 132 Manual Download Page 15

tion. The result is simultaneous generation of a square
wave and triangle wave of the same frequency with

the positive half cycle of the square wave coincident

with the negative slope of the triangle wave.

The magnitude of the capacitor across the integrator

and amplitude of the current into the integrator deter-

mine the frequency of oscillation. Capacitance across

the integrator is changed by rotating the frequency Hz

selector. Amplitude of the current into the integrator

is determined by four parameters which are summed

in the VCG circuit: (1) hysteresis switch output, (2)

the frequency dial voltage, (3) the frequency vernier

voltage, (4) the VCG analog voltage input and (5) the

analog noise when in the FM mode.

The sine wave is produced by feeding the triangle

wave into a shaping network composed of resistors

and diodes. As the triangle wave voltage passes through

zero, loading of the triangle wave is minimal and thus

the slope is maximum.

As  the  triangle voltage in-

creases, diodes with current limiting resistors conduct

and successively cause the slope of the output to be

reduced.

Since the diode break points are mathematically com-

puted and fitted to the true sine shape, the resultant

waveform resembles a pure sine wave. Using a com-

plementary pair of diodes on each break point, the

circuitry is completely symmetrical about ground. The

sine wave, produced by shaping, is considerably less

in amplitude than the triangle wave input and is thus

amplified to be equal to the triangle wave.

Either square, triangle, or sine waveforms can be se-

lected as a signal

source.

The noise source is derived

from a digital filter. A clock oscillator of 160 Hz to

1.6 MHz range functions as a trigger source for the

digital pseudo-random sequence generator (P RSG).

Output of the PRSG is a random binary signal that

can function as digital noise. The number of bits in

each sequence can be selected by the SEQUENCE

LENGTH controls. Parallel data is fed from the PRSG

to the digital-to-analog converter where the informa-

tion is summed and filtered to provide a random

analog noise signal.

The selected sine, triangle, square, analog noise,

or

digital noise signal is routed to the mode control

circuitry where one of the following modes of opera-

tion is selected: Function (FUNC); frequency modula

tion (FM); signal-to-noise (S/N)

;

 or noise-to-signal

(N/S). I n the signal-to-noise and noise-to-signal modes,

one signal is fed to the S/N attenuator and then mixed

with the other signal in the S/N summing amplifier in

a known dB ratio selected by the S/N attenuator. Out-

put of the mode switching circuit is coupled to the

output amplifier. From the output amplifier the signal

is fed to the precision output attenuator and finally to

a

 output connector.

All circuits, except for the hysteresis switch, output

amplifier, and PRSG, operate from

 volt supplies.

The hysteresis switch and power amplifier require

 volts and

 volts, respectively. Operation of the

PRSG requires a  +5 V supply.

12

Summary of Contents for 132

Page 1: ...INSTRUMENT OPERATION AND MAINTENANCE THE INFORMATION IN THIS DOCUMENT MAY NOT BE DUPLICATED IN ANY MANNER WITHOUT THE PRIOR APPROVAL IN WRITING OF WAVETEK SAN DIEGO 9045 Balboa Ave San Diego CA 92123...

Page 2: ...s can be used program ensures that the latest electronic developments individually or combined to provide selectable cali are incorporated into the Wavetek instruments by the brated signal to noise an...

Page 3: ...strument comply with installation instructions MAINT ENANCE may requir e power on w i th th e instrumen t cover sremoved shoul d be don eonly by qualified personne l awar eof the elect h a zards WARNI...

Page 4: ...circuitry is capable of 1000 1 deviation The VCG amplifier has a 100 kHz bandwidth and a slew rate of 0 1 The instantaneous frequency is the result of the sum of the dial setting and the externally a...

Page 5: ...he amount of fre quency deviation NOTE When noise is added to the signal output specifications apply up to 200 kHz and the square wave rise time is dera ted by a factor of 10 In the clock range of 1 6...

Page 6: ...UNC push button Connect oscilloscope to the OUT connec tor with a terminator Set frequency dial to the 1 0 mark and FREQ VERNIER to CAL position Set function selector to the position Set OUTPUT ATTEN...

Page 7: ...nd noise generators This control has no affect on the noise frequency 2 FREQ VERNIER Allows precision electronic control of the signal output frequency A full turn of the control is approximately equa...

Page 8: ...pen circuit providing 20 V peak to peak maxi mum or into a load providing a 10 V peak to peak output OUTPUT ATTEN dB Attenuates the output both signal and noise from 0 dB to 60 dB in six calibrated 10...

Page 9: ...he value to the right of the detent mark VCG IN This connector allows external volt age control of function generator frequency Up to 1000 1 frequency change may be obtained A positive voltage increas...

Page 10: ...termination Select the desired waveform by setting function 1 2 3 4 5 Terminate OUT connector with 50 ohm 2 watt termination Select the desired waveform by setting function selector to or Set FREQ HZ...

Page 11: ...rce 1 Select the desired signal waveform by setting function selector to or 2 Set frequency dial and FREQ HZ range multi plier for desired signal output frequency 3 Depress MODE S N push button 4 Sele...

Page 12: ...t output signal amplitude by setting OUT PUT ATTEN dB control to appropriate atten uation position and fine adjusting signal to de sired amplitude with OUTPUT VERNIER dB control Operation as a Digital...

Page 13: ...lt use Converting a 115 volt unit for 230 volt operation is a simple matter 2 Loosen two captive thumb screws on rear panel and remove panel 1 Remove power cord 3 4 The conversion switch is located on...

Page 14: ...hes function like a Schmitt trigger with the limit points set at the wave form extremes firing when the triangle wave reaches 1 25 volts and 1 25 volts When firing occurs the hysteresis and output swi...

Page 15: ...is considerably less in amplitude than the triangle wave input and is thus amplified to be equal to the triangle wave Either square triangle or sine waveforms can be se lected as a signal source The n...

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