7. 3
Bandwidth Filter Adjustments
Divider Probe, 10
required). . . . . . . . . . . . HP 10432A
Frequency Synthesizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oscilloscope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HP 54501A
Crystal Filter Bypass Network (4
. . . . . . . . . See Figure 3-109
Test Cable: BNC to SMB snap-on . . . . . . . . . . . . . . . . . . . . HP 85680-60093
1.
2.
3.
4.
5.
6.
7.
8.
Position the spectrum analyzer upright as shown in Figure 3-37
and remove the IF-Display Section top cover.
Set the spectrum analyzer LINE switch to ON and press
Connect CAL OUTPUT signal to RF INPUT
Key in
Adjust front panel FREQ ZERO control for maximum signal
amplitude on the CRT display.
Key in
(
CENTER FREQUENCY
)
100 MHz,
[
FREQUENCY
10
1
and press LIN pushbutton.
Press
[
REFERENCE LEVEL
)
and adjust reference level, using step keys and
front-panel knob to place signal peak near top CRT graticule line.
On
3 MHz Bandwidth Filter Assembly connect crystal filter
bypass networks between the two test points above C41 SYM, C32
SYM, C23 SYM, and Cl4 SYM. See Figure 3-38 for the location of
Bandwidth filter.
Adjust
CTR for minimum amplitude of the displayed
signal peak. Adjust
SYM for best symmetry of the
displayed signal. Repeat adjustments to ensure that the displayed
signal is
and adjusted for best symmetry. See Figure 3-38
for location of adjustments.
You may find it helpful to widen and narrow the spectrum analyzer
frequency span to adjust the
symmetry and centering for
each filter stage.
Adjustments 3-77
