HP 8340A Service Manual page 244

correct output waveforms are described in the circuit theory
section for the Phase Frequency Detector, Block D.
test probe with a short ground clip.
good, there will be ringing on the signal edges. Also refer to
the Open Loop Test, below.
Differential Amplifier and Loop Integrators
The bias voltages for Q3 will change with loop conditions. The
three conditions of interest are
frequency less than the 20-30 frequency
and (3) Sampler IF frequency greater than the 20-30 frequency
V),
("lead", YO TUNE > +6.0
these three conditions are given in Table 80-2.
Open Loop Test,
8-328
Model 8340A -.Service
The approximate bias voltages for
V).
below.
Scans by HB9HCA and HB9FSX
If the grounding is not
(1) Loop Locked,
("lag", YO TUNE < -6.0
Also refer to the
Use a 10:1
(2) Sampler IF