HP 3455A Operating And Service Manual page 54

Model 3455A
OC STANDARD
SYSTRON DONNER MODEL MIO6A
3455-B-4733
Section IV
DIGITAL VOLTMETER
hp 34554
CONNECTED TO
CHASSIS GROUND
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2saagse
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Figure 4-6. DC Common-Mode Rejection Test.
h. Set the AC Calibrator for an output of 1 V. Con-
nect the Frequency Counter to the output of the AC
Calibrator and adjust the AC Calibrator's frequency to
50 Hz or 60 Hz + 0.1%, corresponding to the power-
line frequency being used.
i. Record the 3455A reading: Vv.
j. Disconnect the Frequency Counter and connect the
AC Calibrator between the High INPUT terminal and
chassis of the 3455A as shown in Figure 4-7.
k. Without disturbing the frequency setting, set the
AC Calibrator for an output of 70.7 V (100 V peak).
l. The 3455A reading should be within 0.000010 V of
the reading recorded in Step i, verifying that the 50 Hz
or 60 Hz ac common-mode rejection is greater than 160
dB.
m. Without disturbing the frequency setting set the
AC Calibrator for an output of 7.07 V (10 V peak).
Disconnect the AC Calibrator from the 345SA.
n. Remove the 10 K resistor from the 3455A INPUT
terminals. Connect a short jumper between the 3455A
AG CALIBRATOR
hp 745A
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@ 8
bp 5300
ELECTRONIC
COUNTER
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CHASSIS GROUND
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High and Low INPUT terminals.
o. Set the 3455A RANGE to 10 V and record the
display reading:
p. Remove the jumper from the 345SA INPUT ter-
minals, Connect the AC Calibrator output to the 3455A
INPUT.
q. The 3455A reading should be within 00.0100 V of
the reading recorded in Step o, verifying that the 50 Hz
or 60 Hz normal-mode rejection is greater than 60 dB.
r. This completes the Common-Mode and Normal-
Mode Rejection Tests. Disconnect the AC Calibrator
from the 3455A and disconnect the GUARD from the
High INPUT terminal.
4.55. DC VOLTMETER INPUT RESISTANCE TEST.
Equipment Required:
DIGITAL _VOLTMETER
hp 34554
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a VS '
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LW
10K
3485—B- 4734
Figure 4-7, AC Common-Mode Rejection Test.
4-18