Agilent Technologies 856290216 General PLL Troubleshooting

Table 11-5. Sampling Oscillator Test Frequencies
HP 8340A
CW Frequency
(GHz)
6.067000
6.087000
6.110200
6.141000
4.710000
6.174000
6.193000
6.213000
6.066000
6.069000
6.247000
6.107000
3.912000
6.289000
6.321000
6.333000
HP 85633
Center Frequency
(MHz)
Offset PLL
Sampling Oscillator Freq
(MHz)
Counter Reading
Sampler IF
(MHz)
2156.3 285.000 82.000
2176.3 286.364 73.364
2199.5
287.500 72.700
2230.3 288.462 83.308
799.3
288.889
87.778
2263.3 290.000 84.000
2282.3
290.909 83.909
2302.3
291.667
88.000
2155.3
292.500 76.500
2158.3 293.478
94.044
2336.3 294.444 63.667
2196.3 295.000
88.000
1.3
296.000 64.000
2378.3 296.471 63.118
2410.3
297.000 84.000
2422.3 297.222 91.333
General PLL Troubleshooting
The synthesizer section relies heavily on phase-locked loops (PLL). Typically, a faulty PLL
is either locked at the wrong frequency or unlocked. The information below applies to
troubleshooting these two classes of problems on a generalized PLL.
PLL Locked at Wrong Frequency
Numbers in the following text identify items in Figure 11-5:
w Any frequency errors at reference (1) will be multiplied by N/M on the PLL output.
w A sampler reference-frequency error (2) will be multiplied by its harmonic on the PLL
output.
H A mixer reference-frequency error (3) produces the identical error on the PLL output.
w If divider input or output frequencies (4) are wrong, check for incorrect divide numbers and
data controlling the dividers.
Synthesizer Section 1 I-13