Oscillator
Freq.
280.0
282.5
284.0
285.0
286.0
287.5
288.0
290.0
292.0
292.5
294.0
295.0
296.0
297.5
298.0
to 0 Hz and
10. Measure the 280 MHz loop-feedback signal at the following test point:
11. If the feedback signal is not near the indicated power, measure the signal at the following
test points on the feedback path. Refer to function blocks AD, AG, and AH of Al5 RF
Schematic (sheet 3 of 3).
12. Measure the 20 MHz loop-IF signal at the following test point:
13. If the IF signal is not near the indicated power, troubleshoot the loop mixer (function
block AI).
Table 10-15. Sampling Oscillator PLL Divide Ratios
Center Divide TP 406,
I
8
389.5
4
2.5
427.0
4
7
2.5
8
449.5
5
2.0
464.5
6
4
2.5
479.5
7
5
2.0
502.0
4
2.5
5
509.5
6
5
2.0
539.5
5
5
2.0
569.5
4
5
2.0
4
2.5
577.0
3
599.5
5
2.0
3
614.5
2
4
2.5
629.5
2
5
2.0
652.0
1
4
2.5
659.5
1
5
2.0
to the value listed in the table.
N Control
Control
M
Lines
Lines
high high high high low
low high high high low
high high h i g h l o w h i g h
high low high high low
low high h i g h l o w h i g h
l o w l o w high high low
high low h i g h l o w h i g h
l o w l o w h i g h l o w h i g h
high high low
low high
low high low high low
low high low
low high
low high low
high low
l o w l o w h i g h
high low
low
low
low high low
low 1 low
l o w l o w h i g h
0 dBm
+17 dBm
+8 dBm
- 6 dBm