
11. Down/Up Converter Adjustments
6. Adjust
WIDE GAIN to align markers on CRT display.
MKR A level should indicate 1.00 X. See Figure 3-51 for location of
adjustment.
7. Disconnect CAL OUTPUT from RF INPUT.
Optional
Note
Perform the following procedure if
the
assembly is replaced
or the
21.4 MHz
Amplifier Filter is worked on.
1. Disconnect CAL OUTPUT from RF INPUT.
2. Key in
[
REFERENCE LEVEL
)
-70
1
and MARKER
3. Set the second spectrum analyzer’s to
the
following settings:
RESOLUTION BANDWIDTH
. . . . . . . . . . . . . . . . . . 100
FREQUENCY SPAN . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 MHz
CENTER FREQUENCY . . . . . . . . . . . . . . . . . . . . . . 18.4 MHz
RF ATTENUATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
REFERENCE LEVEL . . . . . . . . . . . . . . . . . . . . . . . . . . . 0
SCALE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LOG 10
4. Connect the second spectrum analyzer to
using and
active probe. See Figure
for test setup.
5. Adjust
18.4 MHz NULL to null the 18.4 MHz Local
Oscillator signal and all displayed harmonics. See Figure 3-51 for
location of adjustment.
D O W N / U P C O N V E R T E R
,
4
NIJLL
r
Figure 3-51. Location of Down/Up Converter Adjustments
6. 18.4 MHz signal and displayed harmonics should be below -10
(-30
on display due to
divider). If unable to adjust
18.4 MHz NULL for proper indication, increase value
of
See Figure 3-49 for the location of
Refer
to
3-3 for range of values.
Adjustments 3-93
Summary of Contents for 8568B
Page 13: ...6 7 IF Section Bottom View 6 10 Contents 7 ...
Page 19: ......
Page 37: ......
Page 42: ......
Page 48: ......
Page 53: ......
Page 61: ......
Page 90: ......
Page 106: ...Test 13 Average Noise Level Test 2 84 Performance Tests ...
Page 162: ......
Page 224: ......
Page 268: ......
Page 270: ......
Page 272: ......
Page 278: ......
Page 312: ...AlVl Figure 6 6 IF Section Front View w3 w9 Major Assembly and Component locations 6 9 ...