Pulse Generator (A52) Check With Spectrum Analyzer - Agilent Technologies 8719ET Service Manual

Source Troubleshooting
Broadband Phase Lock Problems

Pulse Generator (A52) Check with Spectrum Analyzer

1. Connect the spectrum analyzer to the network analyzer A65, A sampler assembly (J3)
IF output.
2. Set the parameters on the spectrum analyzer:
• center frequency = 10 MHz
• span = 10 MHz
• marker = 10 MHz
3. On the network analyzer, to set the fractional-N VCO to 180 MHz, press the following:
PRESET: FACTORY
Preset
SERVICE MENU
System
FRACN TUNE ON
SRC ADJUST MENU
4. Slowly turn the network analyzer front panel knob until the spectrum analyzer
measures an output frequency of about 10 MHz.
• If the 10 MHz signal appeared, disregard the rest of this step and continue with the
next step.
• If the 10 MHz signal didn't appear, connect the R sampler assembly IF OUTPUT (J3)
to the spectrum analyzer input.
— If the 10 MHz signal appears on the R sampler assembly but not on the A sampler
assembly, the A sampler assembly is faulty.
— If the 10 MHz signal didn't appear at either the A sampler assembly or the
R sampler assembly, connect the network analyzer's PORT 1 to the spectrum
analyzer input.
• Set the parameters on the spectrum analyzer:
— center frequency = 0.7 GHz
— span = 200 MHz
You should see a signal near the center frequency.
• If a signal is present, the A52 pulse generator is the most probable fault.
5. Reconnect the spectrum analyzer to the A sampler assembly (J3).
6. On the spectrum analyzer, set these parameters:
• center frequency = 10 MHz
• span = 10 MHz
• marker = 10 MHz
7-20
Preset
SERVICE MODES
180 M/µ
DAC NUM LOW BAND 4000 x1
8719ET/20ET/22ET
8719ES/20ES/22ES
RF Network Analyzers
Service Guide