If Bandpass Adjustment; Assembly Adjusted; Related Performance Test; Description - HP 8560E Service Manual

Adjustment Procedures

3. IF Bandpass Adjustment

3. IF Bandpass Adjustment

Assembly Adjusted

A5 IF assembly

Related Performance Test

Resolution Bandwidth Accuracy and Selectivity

Description

The center frequency of each IF bandpass filter pole is adjusted by
DAC-controlled varactor diodes and an inductor (for the LC poles) or a
transformer (for the crystal poles). The inductors and transformers are
for coarse tuning and the varactors are for fine tuning by the
microprocessor. The inductors and transformers are adjusted such that
the varactor diodes are biased near the middle of their capacitance
range. The varactor diode bias is measured with the DVM.
This procedure is not a routine adjustment. It should be performed only
NOTE
if repairs to the A5 IF assembly are made. If the entire A5 IF assembly
is replaced, the assembly arrives pre-adjusted from the factory and
requires no further adjustment.
Figure 2-5 IF Bandpass Adjustment Setup
70 Chapter 2