
Section V
5-36.
Output Adjustments.
5-37. Amplitude Adjustment.
a . Connect 652A to ac voltmeter, as shown in Figure
5-2.
b. Set 652A controls as follows:
FREQUENCY RANGE . . . . . . . . . . . . . . XIO
FREQUENCY dial . . . . . . . . . . . . . . . . . . . . I
OUTPUT ATTENUATOR . . . . . . . . . . 3.0 V
AMPLITUDE . . . . . . . . . . . . . Fully Clockwise
c. AC Voltmeter should indicate at least 3 . 1 6 V rms. If
maximum output is less than 3.16 V, slightly decrease value
of A2R24*.
5-38. Waveform Adjustment.
a. Connect a 50
n
load to a 652A 50
n
output
terminal, and connect the output to an oscilloscope.
b. Set OUTPUT ATTENUATOR to 3.0 V, and turn
OUTPUT AMPLITUDE and VERNIER controls fully coun
terclockwise.
c. Check 652A output with and without load on all
frequencies for spurious oscillations. Spurious oscillations
most likely occur in the output amplifier. A slight increase
in the value of A2R29 should eliminate this. If spurious
oscillations still occur, then change the value of A2C21
slightly. (If A2C21 is changed, then recheck I MHz
Frequency Calibration, Paragraph 5·33.)
d. Since there is a· direct interaction between Wavefonn
Adjustment and Amplitude Adjustment, recheck Ampli
tude Adjustment.
5�39. Minimu m Distortion Adjustment.
a. Connect 652A to distortion analyzer as shown in
Figure 5·5.
b. Set 652A controls as follows:
FREQUENCY RANGE . . . . . . . . . . . . . . XI K
FREQUENCY dial . . . . . . . . . . . . . . . . . . . . I
OUTPUT ATTENUATOR . . . . . . . . . . 3.0 V
OUTPUT AMPLITUDE
and VERNIER . . . . . . . . . . Fully clockwise
c. Adjust A2RI7 for minimum distortion as indicated
on distortion analyzer. Distortion should be less than 1 %
(40 d B down).
NOTE
Distortion will be typically 50 dB down.
5 - 1 4
MOdel
bolA
5-40. Normal Monitor Calibration.
NOTE
The following adjustments are critical. Final
voltage, measurements must be made with all
instrument covers in place.
a. Connect 652A to ac voltmeter as shown in Figure
5-2.
b. Set 652A controls as follows:
FREQUENCY RANGE . . . . . . . . . . . . . XI 00
FREQUENCY dial . . . . . . . . . . . . . . . . . . . . 4
OUTPUT AMPLITUDE . . . . . . . . . . . . 3.0 V
OUTPUT MONITOR . . . . . . . . . . . .
NORMAL
c. Set OUTPUT AMPLITUDE and VERNIER controls
for a 3.0 V rms indication on ac voltmeter.
d. Adjust A l R23 for a 3.0 V indication on 652A
monitor. If AI R23 does not have sufficient range to
properly calibrate monitor, change value of Al Rn*.
(Increasing A l R22 * increases monitor indication and vice
versa.)
e. Set 652A FREQUENCY RANGE to XIM, and
FREQUENCY dial to 1 0.
f.
Set 652A OUTPUT AMPLITUDE and VERNIER
controls for a 3.0 V rms indication on ac voltmeter.
g. Making allowance for any error of the ac voltmeter at
1 0 MHz, adjust A I C l 5 for a 3.0 V indication on 652A
monitor.
If
necessary, change value of A2C25*.
NOTE
If
ac voltmeter error at 1 0 MHz is not known,
follow this
alternative procedure.
b.
Perform Steps a through d .
i . Connect equipment a s shown i n Figure 5-3 and adjust
reference supply for null indication on null meter.
j. Set 652A FREQUENCY RANGE to XIM and FRE
QUENCY dial to 1 0.
k. Adjust 652A OUTPUT AMPLITUDE and VERNIER
controls for null indication on null meter. Do not readjust
reference supply.
I. Adjust AICI 5 for 3.0 V indication on 652A monitor.