
17. 20/30 Loop Phase Lock Adjustments
Phase
Lock Loop
3
1. Set the RF Section LINE switch to STANDBY. Remove
AlOA4
(P=9
2.
3.
4.
PLL3 Up Converter Assembly from the RF Section, and install it
on an extender board. Reconnect the cable 7 (violet) to
AlOA5J4
SCAN
I.1
MHz OUT and the cable 8 (gray) to AlOA4J3 IN 100
MHz.
Connect the RF INPUT of the second spectrum analyzer to SMB
test connector
AlOA4J4.
Refer to Figure 3-80 for the location of
test connector
AlOA4J4.
AlOA4
PLLJ
UP
CONVERTER
TOP VIEW
AlOA4
CA,10
Figure 3-80. Location of
PLL3
Adjustments
Set the RF Section LINE switch to ON, and key in
(j-1,
[FREQUENCY
SPAN
)
0
HZ
.
On the second spectrum analyzer, key in
@Z-G@,
LSHIFT)
@TART
FREQ~.
Set the controls of the second spectrum analyzer
as follows:
CENTER FREQUENCY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 MHz
FREQUENCY SPAN
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.200
kHz
RES BW (MANUAL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
kHz
REFERENCE LEVEL . . . . . . . . . . . . . . . . . . . . . . . . . . -20
dBm
Note
In addition to the displayed 160 MHz signal, other signals should be
present at
AlOA4J4
at approximately 160.3 MHz and 300
kHz.
5. On the second spectrum analyzer, key in MARKER (PEAK SEARCH),
MKR
+
REF
LVL
to position the peak of the displayed 160 MHz
signal at the top CRT graticule line. Then, key in [ENTER dB/DIv)
2
dB,
[FREQUENCY SPAN) 50
kHz,
[REFERENCELEVEL)
STEP
@‘j
@
@)
on the second spectrum analyzer to lower the peak of the
displayed signal by three major graticule divisions.
3-156 Adjustments
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