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Adjustment of the carrier signal for minimum amplitude is
critical. Do not attempt to null the carrier signal until the
correct Res BW is reached. Incorrect adjustment can result in
loss of traffic due to slow RCVR lock.
g
Observe the display at the correct
Res BW
for measuring carrier for a
carrier signal rising above the floor of the spectrum. Is a carrier signal
rising 3 dB or more above the spectrum visible?
No. STOP. This procedure is complete. Carrier is nulled to an
acceptable level.
Yes.
1)
Continue to reduce the frequency span until the spectrum
analyzer shows a Res BW equal to or lower than the
Res
BW For Nulling Carrier
value shown in the table.
2)
Alternately adjust the I Carr and Q Carr controls on the
XMTR module for minimum carrier amplitude. Refer to
the following typical scenario for adjustment tips/prob-
lems.
TYPICAL ADJUSTMENT SCENARIO
Refer to the following step-by-step adjustment of 3 DS3/64 QAM radio. In this scenario,
carrier null adjustment is required due to slow RCVR lockup following a deep fade. The
Res BW
for nulling carrier for the 3 DS3/64 QAM radio is 3 kHz as listed in the table.
CAUTION
Possibi
l
ity of
Service
I
n
terr
u
ptio
n
Содержание MDR-8000
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