Tabor 8020, User Manual

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7-3-11. Triangle Flatness Adjustments
Equipment: Oscilloscope, 50 ohms feedthrough termination
1 . Change 8020 Function setting to Triangle.
2 . Change 8020 Frequency setting to 100.0 KHz.
3 . Change 8020 Amplitude setting to 15.0 V.
4 . Connect 8020 OUTPUT, through a 50 ohms feedthrough
termination, to the oscilloscope.
5 . Adjust oscilloscope controls to display the triangle with
exactly 6 vertical divisions peak to peak.
6 . Change 8020 Frequency setting to 20 MHz.
7 . Select C7 (approximately 15PF), on the amplifier board
assembly, so that the triangle amplitude on the screen will be
within the range of 5.1 to 5.3 vertical divisions.
7-3-12. Reference Oscillator Adjustment
Equipment: Counter
1 . Set counter for frequency measurements. Using a :10
probe, measure the frequency at pin 3 of U14.
2 . Select C68, on the main board assembly, for a counter read-
ing of 5.0000 MHz +/- 100 Hz.
7-3-13. Pulse Width Adjustment (model 8021 only)
Equipment: Counter
1 . Connect 8021 output through a 50 ohms feedthrough ter-
mination to the counter input. Set counter and 8021 settings
and adjust controls on the final amplifier board assembly, as
follows:
8021 WID 8021 FREQ COUNTER
SETTING SETTING ADJUST READING
5.00 mS 100.0 Hz R211 5.00 mS +/-50 uS
500 uS 1.000 KHz R211* 500 uS +/-5 uS
50.0 uS 10.00 KHz C84 50.0 uS +/-.5 uS
500 nS 1.000 MHz C89 500 nS +/-10 nS
25.0 nS 1.000 MHz R188 25.0 nS +/-2 nS
(Repeat last two steps)
5.00 uS
100.0 KHz C86 5.00 uS +/-50 nS
* Repeat adjustments until best accuracy is achieved.
7-3-14. Ramp Amplitude Adjustment (model 8021 only)
Equipment: Oscilloscope
1 . Set 8021 output to ramp, frequency setting to 1.000 KHz,
pulse width setting to 500 uS and amplitude setting to 6.0 V.
2 . Set oscilloscope input to DC coupling and vertical gain to
be 1 V/div. Adjust trace vertical position so that it appears 3
divisions below the center line.
3 . Connect 8021 output, through a 50 ohms feedthrough ter-
mination, to oscilloscope input. Select R218 so that the base
line is set to three divisions below the center line.
4 . Adjust R213 for a peak to peak amplitude of 6 vertical di-
visions.
7-3-15. Amplitude Modulation Adjustment (model 8022
only)
Equipment: Oscilloscope, function generator, DMM
1 . Set 8022 output to AM mode on, frequency setting to 1.000
KHz, amplitude setting to 15.0 V, output setting to sine wave-
form and carrier setting to 0 %.
2 . Connect 8022 output, through a 50 ohms feedthrough ter-
mination, to DMM input. Set DMM to ACV and 200 mV
range. Adjust R135, on the final amplifier board, for a DMM
reading of 0 V +/-20 mV.
3 . Change 8022 carrier setting to 100 %. Adjust R174 for a
DMM reading of 2.65 V +/-10 mV.
4 . Change 8022 carrier setting to 0 % and trigger mode setting
to TRIG.
5 . Set external function generator to output sine waveform at
1.000 KHz and 4 Vp-p amplitude. Connect external gener-
ator to 8022 AM input and adjust R142 for a DMM reading of
0 V +/-20 mV. Remove external generator from 8022 AM
input.
6 . Change 8022 carrier setting to 100 % and gated mode. Set
DMM to DCV and 200 mV range. Adjust R159 for a DMM
reading of 0 V +/-20 mV. Disconnect 8022 output from
DMM.
7 . Set external function generator to output sine waveform at
1.000 KHz. Connect external function generator to 8022 AM
input.
8 . Connect 8022 output, through a 50 ohms feedthrough ter-
mination, to the oscilloscope. Connect 8022 SYNC output to
oscilloscope external trigger input. Set oscilloscope to exter-
nal trigger.
9 . Change 8022 frequency setting to 1 MHz.
10 . Adjust external function generator amplitude until the
trace on the oscilloscope exhibits 100 % modulation. Re-ad-
just R142 for equal positive and negative portions of the
modulated signal. Note and record peak to peak amplitude
level.
11 . Change 8022 carrier setting to 0 %. The oscilloscope now
displays an SCAM waveform (suppressed carrier amplitude
modulation). Modify external function generator amplitude
so that the peak to peak amplitude is exactly as noted before.
If necessary re-adjust R135 for equal positive and negative
portions of the modulated signal.
Adjustments Model 8020
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