Log Amplifier Adjustments; Log Amplifier Adjustments Setup - HP 8566B Adjustment Manual

IF-Display Section
Scale Fidelity Test
The A4A3 Log Amplifier-Filter and A4A2 Log Amplifier Detector
are temperature compensated as a matched set at the factory. In
the event of a circuit failure, a new matched set must be ordered.
Contact your nearest HP Service Center.
The A4A2 Log Amplifier-Detector ZERO adjustment is checked and
adjusted if necessary, then the A4A3 Log Amplifier-Filter is set for
center frequency by injecting a signal and adjusting the bandpass filter
center adjustment for maximum DVM indication. The bandpass filter
amplitude is adjusted by monitoring the output of the filter control
line shorted and not shorted to the + 15V supply. Next, log fidelity
(gain and offset of the log curve) is adjusted by adjusting the -12 VTV
and the PIN diode attenuator. Last, the linear gain step adjustments
are performed to set the proper amount of step gain in the linear
mode of operation.
Figure 3-33. Log Amplifier Adjustments Setup
Digital Voltmeter (DVM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HP 3456A
Frequency Synthesizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HP 3335A

5. Log Amplifier Adjustments

Adjustments 3-69