2 1. Frequency Response Adjustments
peaks of these responses coarsely outline the spectrum analyzer
frequency response.
S T A R T
1 2 . 5 8
q W 3 MHZ
q W 3 MHZ
3 MHZ
3 MHZ
2.00
2.00
Figure 3-97.
Figure 3-97.
Typical Coarse Frequency Response (5.8
12.5
Typical Coarse Frequency Response (5.8
12.5
It might be helpful to temporarily change the spectrum analyzer
@
WEEP TIME
]
setting while adjusting frequency response, particularly
when making fine adjustments. An increase in spectrum analyzer
sweep time results in closer spacing of the displayed responses, but
slows the adjustment. Do not decrease the
(
SWEEP TIME
)
setting below
before the YTX Delay Compensation adjustments have been made.
98. Gradually adjust (Band C Lower Segment)
Cl and
(Band C Upper Segment)
C2 for maximum flatness of
the displayed signal responses. The adjustments are interactive,
with
Cl having the most effect on the level of the
displayed signals below mid-band (approximately 9.1
and
C2 having the most effect on the level of
the displayed signals above mid-band. Adjust
Cl
counterclockwise to increase the level of the displayed signal
responses below mid-band. Adjust
C2 clockwise
to increase the level of the displayed signal responses above
mid-band. See Figure 3-90 for the locations of
Cl and
C2.
If the displayed signals at the high end of the band drop off by more
than 2-3
center
C2 and proceed to step 99.
99. On the spectrum analyzer, key in
(
SWEEP
LOG SCALE
(
ENTER
1
TRACE B
4,
(
SWEEP TIME
]
TRACE B
[HOLD).
100. Readjust
(YTX Diode Bias) potentiometer
VC
to maximize the overall level of the displayed signal responses
from 5.8
to 12.5
on the spectrum analyzer display.
Then, adjust
VC clockwise until signal responses at
the high end of the band drop in amplitude by approximately 0.5
Adjustments 3-191
