M Ohm Input Impedance Test - HP 3585A Service Manual

Model 3585A
4·37. 1 M Ohm Input Impedance Test
These tests verify that the 3585A meets the Input Impedance specifications for the 1 MO, 30
pf Input Impedance setting.
Specification: I MO ± 3 % ,
Equipment Required:
Resistor: I MO ± 1 % , 1 I8W film . . . . . . . . -hp- Part No. 0757-0344
500 Feed Thru Termination . . . . . . . . . . . . . . . . . . . . . . -hp- 1 l048C
Synthesizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -hp- 3335A
Procedure:
a. Set the 3585A controls as follows:
b. Set the synthesizer controls for:
c. Connect the 500 termination to the 3585A 1 MO input. Connect the synthesizer output
to the termination input.
d . Set the 3585A controls for OFFSET on. Allow time for the marker reading to stablize
and press the ENTER OFFSET button.
e. Using short clip leads, insert the 1 MO resistor between tne output of the termination
and the 3585A 1 MO input as shown in Figure 4-9.
f. The 3585A marker amplitude reading should be -6.0 dB ± 0.44 dB, verifying that the
jnput resistance is 1 MO ± 5 1170 .
g. Press the 3585A ENTER OFFSET button.
h. Set the synthesizer frequency to 10 kHz.
i. Set the 3585A for a CENTER FREQUENCY of 10 kHz.
j . The 3585A marker reading should be between -1 dB and -3 dB, verifying that the shunt
capacitance is less than 30 pf.
<
30 pf
INSTRUMENT PRESET
CENTER FREQUENCY . . . . . . . . . . . . . . . . . 1 kHz
MANUAL SWEEP . . . . . . . . . . . . . . . . . . . . . . . . on
RES. BW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 00 Hz
dB/DIV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 dB
RANGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 dBm
INPUT IMPEDANCE . . . . . . . . . . . . . . . . . . . 1 MO
FREQUENCY . . . . . . . . . . . . . . . . . . . . . . . . . 1 kHz
AMPLITUDE . . . . . . . . . . . . . . . . . . . . . . . . . 0 dBm
Performance Tests
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