Mhz Frequency Standard Adjustments Setup - HP 8566B Adjustment Manual

12. 10 MHz Standard Adjustment (SN 2728A and Above)
Replacement oscillators are factory-adjusted after a complete warmup
and after the specified aging rate has been achieved. Readjustment
should typically not be necessary after oscillator replacement, and is
generally not recommended.
1. Set the rear-panel FREQ REFERENCE switch on the spectrum
analyzer RF Section to INT.
The +22 Vdc STANDBY supply provides power to the heater circuit in
the A22 10 MHz Frequency Standard assembly whenever line power
is applied to the RF Section. This allows the A22 10 MHz Frequency
Standard oven to remain at thermal equilibrium, minimizing
frequency drift due to temperature variations. The OVEN COLD
message should typically appear on the spectrum analyzer display for
10 minutes or less after line power is first applied to the RF Section.
The rear-panel FREQ REFERENCE switch enables or disables the RF
Section +20 Vdc switched supply, which powers the oscillator circuits
in the A22 10 MHz Frequency Standard. This switch must be set to
INT and the spectrum analyzer must be switched ON continuously
(not in STANDBY) for at least 72 hours before adjusting the frequency
of the A22 10 MHz Frequency Standard.
2. Set the LINE switch to ON. Leave the spectrum analyzer ON
(not in STANDBY) and undisturbed for at least 48 hours to allow
the temperature and frequency of
Standard to stabilize.
To prolong CRT life, press
CRT display while the spectrum analyzer is unattended, and (SHIFT]
3. Connect the (Cesium Beam) Frequency Standard to the Frequency
Counter rear-panel TIMEBASE IN/OUT connector as shown in
Figure 3-54.
Figure 3-54. 10 MHz Frequency Standard Adjustments Setup
the
A22 10 MHz Frequency
(SHIFT] (CLEAR-WRITES)
to turn off the
Adjustments 3-l 09