
11. Down/Up Converter Adjustments
Down Converter Gain
Adjustment
Note
If a gain problem is suspected in the 10 Hz to 1
resolution
bandwidths, perform the following procedure to test and adjust the
gain through
1. Place
on extender boards.
2. On the spectrum analyzer being tested, press
PRESET
],
and set
the spectrum analyzer to the following settings:
CENTER FREQUENCY . . . . . . . . . . . . . . . . . . . . . . . . 20 MHz
RESOLUTION BANDWIDTH
. . . . . . . . . . . . . . . . . . . . . 1
FREQUENCY SPAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 Hz
REFERENCE LEVEL . . . . . . . . . . . . . . . . . . . . . . . . -10
INPUT ATTENUATION . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3. Connect an active probe to a second spectrum analyzer, and set the
spectrum analyzer to the following settings:
CENTER FREQUENCY . . . . . . . . . . . . . . . . . . . . . . 21.4 MHz
RESOLUTION BANDWIDTH
. . . . . . . . . . . . . . . . . . 100
FREQUENCY SPAN . . . . . . . . . . . . . . . . . . . . . . . . . .
Hz
REFERENCE LEVEL . . . . . . . . . . . . . . . . . . . . . . . -30
INPUT ATTENUATION . . . . . . . . . . . . . . . . . . . . . . . . . . 10
SCALE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LOG 1 dB/div
4. Measure the signal at
using the active probe and
record below. The signal level should be approximately -33
Signal level at
5. Change the center frequency of the spectrum analyzer used
for measuring the signals to 3 MHz. Measure the signal at
The signal level should be 10
lower than
the signal measured in the previous step.
Signal level at
6. If the signal at
needs adjusting, change
(Decreasing
ten percent increases the signal level by 0.6
Refer to Table 3-3 for the acceptable range of values for
3-94 Adjustments
Summary of Contents for 8568B
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