Agilent Technologies HP 8719D Service Manual page 284

PLL DIAG on OFF (SM5)
Service Modes More
(reference) channel. For example, in a high power
test application, using band limited filters for R
channel phase locking.
displays a phase lock sequence at the beginning of
each band. This sequence normally occurs very
rapidly, making it difficult to troubleshoot phase lock
problems. Switching this mode ON slows the process
down, allowing you to inspect the steps of the phase
lock sequence (pretune, acquire, and track) by
pausing at each step. The steps are indicated on the
display, along with the channel (Cl or C2) and band
number (Bl through B13).
This mode can be used with PLL PAUSE to halt the
process at any step. It can also be used with the
analog bus counter.
is used only with PLL DIAG mode. $XlrlT indicates
that it will continuously cycle through ail steps of
the phase lock sequence. ~P&?SE holds it at any step
of interest. This mode is useful for troubleshooting
phase-locked loop problems.
accesses the service modes more menu listed below.
Menu
is used for normal operating conditions and works
in conjunction with IF GAIN ON and OFF. The A10
assembly includes a switchable attenuator section
and an amplifier that amplifies low-level 4 kHz
IF signals (for A and B inputs only). This mode
allows the A10 IF section to automatically determine
if the attenuator should be switched in or out.
The switch occurs when the A or B input signal is
approximately -30 dBm.
locks out the A10 IF attenuator sections for
checking the A10 IF gain amplifier circuits,
regardless of the amplitude of the A or B IF signal.
Service Key Menus and Error Messages
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