Agilent Technologies HP 8719D Service Manual page 231

that Al3 and Al4 are functional: go to "Check Pulse Generator" or
continue with "A14 VCO Range Check with Oscilloscope" to conlirm.
with Spectrum
Analyzer
2. Set the parameters on the spectrum analyzer:
start frequency = 50 MHz
stop frequency = 250 MHz
bandwidth = 300 kHz
3. Remove the instrument bottom cover and disconnect the A52Jl cable from
the A52 Pulse Generator.
4. Connect the spectrum analyzer to the output of Al4 via the A52Jl cable.
5. Slowly turn the network analyzer front panel knob to tune the signal across
the entire frequency range.
You should see a signal that is about 0 dBm at 120 MHz and below. You
should see the signal drop approximately 2.5 dB above 120 MHz.
6. Look for sidebands on the signal.
The signal should appear very clean without any sidebands present, however,
you will observe source harmonics
fractional-N analog assembly.
tuning the signal across the frequency range, there could be a faulty Al4
fractional-N digital assembly.
If a clean signal appears across the entire frequency range, you can assume
n
that the Al3 (fractional-N analog) and the Al4 (fractional-N digital)
assemblies are working correctly.
Source Troubleshooting