HP 8568B, Performance Tests And Adjustments Manual, Page: 201 / 313

10. Step Gain and 18.4 MHz Local Oscillator Adjustments
10. Step Gain and
18.4 MHz Local
Oscillator
Adjustments
Reference
Related Performance
Tests
Description
IF-Display Section
3 MHz Bandwidth Filter
Step Gain
Resolution Bandwidth Selectivity Test
IF Gain Uncertainty Test
Center Frequency Readout Accuracy Test
First, the IF signal from the RF Section is measured with a power
meter and adjusted for proper level. Next, the 10
gain steps are
adjusted by connecting the CAL OUTPUT signal through two step
attenuators to the RF INPUT and keying in
the
REFERENCE LEVEL
necessary to activate each of the gain steps, while compensating for
the increased gain with the step attenuators.
The 1 gain steps are checked in the
same
fashion as the 10
gain steps, and then the variable gain is adjusted. The 18.4 MHz
oscillator frequency is adjusted to provide adequate adjustment range
of front-panel FREQ ZERO control; and last, the + temperature
compensation supply used by the Bandwidth Filter and
Attenuator-Bandwidth Filter is checked and adjusted if necessary.
METER
S T E P 1 S T E P
ATTENUATOR ATTENUATOR
DIGITAL VOLTMETER
Figure 3-46.
Step Gain and 18.4 MHz Local Oscillator Adjustments Setup
Adjustments 3-87