
17. 20/30 Loop Phase Lock Adjustments
AlOAl
AlOA3
PLLl
vco
PLLl
IF
\
n/
TOP VIEW
Ll3
170MHz
NULL
L12
160MHz
NULL
Lll
165MHz
NULL
C26*
Al OA3
TP3
Place Act
Probe her
L7
5OkHz
NULL
LN8UL5LOkHZ
AlOAT
ive
e
Figure 3-78. Location of PLLl Adjustments
12. On the second spectrum analyzer, press [CENTER FREQUENCY) 100
MHz [FREQUENCY SPAN) 6 MHz MARKER [PEAK SEARCH) to place the
second marker on the displayed 50
kHz
signal. This level should
be at least 65
dB
down from the level of the 20
kHz
signal in step
9.
13. Disconnect the active probe and frequency synthesizer from
AlOAl PLLl VCO Assembly.
14. Install AlOAl PLLl VCO Assembly in the RF Section using an
extender board. Reconnect the cable 1 (brown) to
AlOA5J5
SCAN
.l-5 MHz OUT and the cable 5 (green) to
AlOAlJ2
OUT 20-30
MHz.
15. Set the RF Section LINE switch to ON, and key in
@Z!Zi@,
[FREQUENCY
SPAN]
0 HZ.
16. Disconnect the active probe from the RF INPUT of the second
spectrum analyzer.
17. Press @ZZiZ] on the second spectrum analyzer. Connect the CAL
OUTPUT signal to the RF INPUT
on
the second spectrum analyzer,
and press
(RECALL].
18. Adjust the AMPTD CAL control on the second spectrum analyzer
for a -10.00
dBm
displayed signal, and then press
m
CFREQUENCY
sPAN)~.
19. Use a BNC to SMB Snap-on Test Cable to connect the RF INPUT of
the second spectrum analyzer to
AlOAlJ3
OUT 200-300 MHz.
Adjustments 3-149
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