Agilent Technologies 8753ES Option 011 Service Manual page 247

Source Troubleshooting
Phase Lock Error
PLREF Waveforms
REF Signal At A11TP9 REF is the buffered PLREF+ signal. The 1st IF is phase locked
to this signal. Use an oscilloscope to observe the signal at the frequencies noted in Figure
7-9 and Figure 7-10.
High Band REF Signal In high band the REF signal is a constant 1 MHz square wave
as indicated by Figure 7-9.
Figure 7-9 High Band REF Signal (≥16 MHz CW)
Low Band REF Signal In low band this signal follows the frequency of the RF output
signal. Figure 7-10 illustrates a 5 MHz CW signal.
Figure 7-10 REF Signal at A11TP9 (5 MHz CW)
• If REF looks good, skip ahead to "4 MHz Reference Signal" on page 7-16.
• If REF is bad in low band, continue with "FN LO at A12 Check," next.
Chapter 7 7-15