Chapter 7 7-25
Source Troubleshooting
Phase Lock Error
Figure 7-22 H MB Signal at A14P1-5 (Preset and 16 MHz to 31 MHz Sweep)
A7 Pulse Generator Check
The pulse generator affects phase lock in high band only. It can be checked with either a
spectrum analyzer or an oscilloscope.
A7 Pulse Generator Check with Spectrum Analyzer
1. Remove the A7-to-A6 SMB cable (W7) from the A7 pulse generator assembly. Set the
analyzer to generate a 16 MHz CW signal. Connect the spectrum analyzer to the
A7 output connector and observe the signal. The A7 comb should resemble the spectral
display in Figure 7-23.
Figure 7-23 Pulse Generator Output
2. If the analyzer malfunction relates to a particular frequency or range, look more closely
at the comb tooth there. Adjust the spectrum analyzer span and bandwidth as required.
Even at 3 GHz, the comb should look as clean as Figure 7-24. For Option 006
instruments at 6 GHz, the comb tooth level should be approximately −46 dBm.