Model 3585A
Adjustments
REF -25. 0 dBm
MARKER 20 000 (JOO. O Hz
10 dB/O I V
RANGE -25. 0 dBm
-37. 1 dBm
,
,
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- - - -
- - - -
- - - -
- - - -
t
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- - - - . - - - -
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-
- -
CENT E R 20 000 000. 0 H z
SPAN 4 0 000 000. 0 Hz
RBW 30 KHz
VBW 30 KHz
ST . 2 SEC
Figure 5·38. Normal Display For Test Mode 05
5·36. Flatness Adjustment
a. Move test jumper A15W1 to the "TEST" position.
b. Set the 3585A controls for:
RECALL 605
INSTRUMENT PRESET
CENTER FREQUENCY . . . . . . . . . . . . . . . . . . 20. 1 MHz
dB/DIV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2dB
RANGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - 25dBm
AUTO RANGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . off
c. Using the Continuous Entry control, adjust the REF LVL so that the trace is centered
on the CRT.
d. The 3585A is now in its 0.2dB/DIV mode. This allows very fine adjustment of the in
struments flatness.
e. Adjust the input flatness with the following components in the order shown.
A 1 R 1 3 1 , C83, L 1 8, C86, L19, C89, L21 , C92
The input flatness of the instrument should resemble Figure 5-39 when completely adjusted.
The effect of each adjustment is shown in Figure 5-40 (foldout). Continue adjustment of the
instrument flatness until the peak to peak variation of the trace is less than 0.2dB
(l
division).
f. Move test jumper A 1 5W 1 to the "NORM" position.
5-59