Model 3585A
Performance Tests
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 % ,
<
30 pf
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:
INSTRUMENT PRESET
CENTER FREQUENCY . . . . . . . . . . . . . . . . . 1 kHz
MANUAL SWEEP . . . . . . . . . . . . . . . . . . . . . . . . on
RES. BW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 Hz
dB/DIV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 dB
RANGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 dBm
INPUT IMPEDANCE . . . . . . . . . . . . . . . . . . . 1 MO
b. Set the synthesizer controls for:
FREQUENCY . . . . . . . . . . . . . . . . . . . . . . . . . 1 kHz
AMPLITUDE . . . . . . . . . . . . . . . . . . . . . . . . . 0 dBm
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 ± 51170 .
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.
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