119. On the spectrum analyzer, key in LOG SCALE
(
ENTER
2
MARKER
120. Readjust 22-turn (IF Offset) potentiometer
D as
necessary to maximize the amplitude of
the 15.0
signal on
the spectrum analyzer display.
121. Set the synthesized sweeper controls as follows:
START FREQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
STOP FREQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18.6
RF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . on
LEVELING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XTAL
SWEEP TIME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ms
SWEEP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CONT
122. On the spectrum analyzer, key in TRACE A
[
CLEAR
-
WRITE
),
(
SWEEP TIME
)
MARKER (OFF), (HOLD. As the spectrum
analyzer completes each sweep, a series of approximately 22 new
responses should be displayed, as shown in Figure 3-98. The
peaks of these responses coarsely outline the spectrum analyzer
frequency response.
123. Gradually adjust (Band D Lower Segment)
and
(Band D Upper Segment)
D2 for maximum flatness of
the displayed signal responses. The adjustments are interactive,
with
having the most effect on the level of
the displayed signals below mid-band (approximately 15.5
and
D2 having the most effect on the level of
the displayed signals above mid-band. Adjust
counterclockwise to increase the level of the displayed signal
responses below mid-band. Adjust
D2 clockwise
to increase the level of the displayed signal responses above
mid-band. See Figure 3-90 for the locations of
and
D2.
2 1. Frequency Response Adjustments
the displayed 15.0
signal. Adjust 17-turn (Band D Step
Gain) potentiometer
GD as necessary to adjust the
amplitude of the displayed 15.0
marker to -10.00
fO.10
Adjust
GD counterclockwise to increase
the signal level, and clockwise to decrease the signal level.
If
GD does not have sufficient range, adjust the
amplitude of the displayed 15.0
marker as close as possible
to -10.00
See Figure 3-90 for the location of
GD.
If the displayed signals at the high end of the band drop off by more
than 2-3
center
D2 and proceed to step 125.
124. On the spectrum analyzer, key in
TIME
)
LOG SCALE
[
ENTER
1
TRACE B [VIEW), (SAVE) 4,
TRACE B [BLANK),
125. Readjust 17-turn (YTX Diode Bias) potentiometer
VD
to maximize the overall level of the displayed signal responses
from 12.5
to 18.6
on the spectrum analyzer display.
Then, adjust
VD clockwise until signal responses at
Adjustments 3-195
