
14. 100 MHz VCXO Adjustments
output signal. Verify that the 100 MHz harmonics do not exceed
the levels listed in
‘Iable
3-8
‘Ihble
3-8. Limits for 100 MHz Harmonics
20. Set the controls of the second spectrum analyzer as follows:
CENTER FREQUENCY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.400
MHz
FREQUENCY SPAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
kHz
REFERENCE LEVEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -7 dBm
RES BW
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 Hz
LOG SCALE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 dB/div
21. Slightly readjust the
A7A2C3,
A7A2C2,
and
A7A2Cl
400 MHz
adjustments in sequence to maximize the power level of the 400
MHz output signal, and then verify that the maximized power
level of the 400 MHz output signal is -10
dBm
f2
dB.
If it is not,
note the amplitude and change the values of attenuator network
resistors
A7A2R67,
A7A2R68,
and
A7A2R69
as necessary.
‘Iable
3-9 contains a list of attenuations in
1-dB
steps and the
corresponding
values for the attenuator resistors to adjust the 400 MHz
output power level to -10
dBm.
Refer to Table 3-10 for HP
part numbers, and to Figure 3-65 for the location of
A7A2R67,
A7A2R68,
and
A7A2R69.
‘Ihble
3-9.
Selection Chart for Attenuator Resistors
1
Resistors
1
Attenuation
(dB)
0
-1
-2
-3
-4
-5
-6
-7
-8
-9
R67
open
825
422
261
215
178
147
133
121
110
R68
short
6.8
12.1
17.8
23.7
31.6
38.3
46.4
51.1
61.9
R69
open
825
422
261
215
178
147
133
121
110
3-130
Adjustments
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