Motorola R-2400 Operator's Manual page 42

6. To
check the transmitter's distortion, connect
the
service monitor's "Demod
out" to
the,ryert/
SINAD
/Dist"
input jack. set
left LCD to
,,Dist"
and read
Vo
distortion on the display.
If
using an R-2400, the
"pwr Mon/Anlzr on"
function
may
be used
alternatively, to
observe both the modula-
tion,
recovered
demod and frequency spectrum
signals.
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FIGURE
5.11
-
DUPLEXER PASSBAND
ADJUSTMENT
SETUP
5.14.0 CAVITY AND
DUPLEXER TUNING
BANDPASS ADJUSTMENT
A.
Passband
Adjustment
l.
connect
the
service
monitor's "RF
Inlout"
to
the
in-service duplexer antenna
port
as shown in
figure
5.11.
2. set left
LCD
to
"Dev", "Function" switch
to
"Gen",
"FM",
and modulation switch to
"off'
position.
3.
Enter the receiver frequency.
4.
set
the RF step attenuator
to -30 dB
and
the,,RF
vernier" to
mid-ratrge, to
allow
adequate signal
to
get through
a mistuned duplexer and quiet
the
receiver.
Reduce the signal generator output,
as
necess iltY
,
to
keep the receiver limiter
meter read-
ing below saturation. use
"Hi
Gen"
and the
*An-
tenna"
port if
the duplexer
is
badly mis-tuned,
to
start.
5.
Tune the
pass-band knobs
of
the cavities in
the
duplexer
receive leg,
for
a
peak reading on the re-
ceiver
limiter
meter.
Reduce the signal
generator
output,
?S
necess&ty, to
keep the
receiver
limiter
meter reading
below saturation. This
completes
the pass-band
adjustment
for
the
receiver
leg.
6.
Set
the "Function" switch to
,,pow Mon',
(or
"Pwr Mon/Anlzr on")
and the attenuator to
-30 dB. For
low-power transmitters,
it
may
be
necess
ary to
reduce the attenuator setting to un-
squelch the
monitor. Too
high
an attenuator
set-
ting or too tight a
squelch setting
will inhibit
the
display
of
frequency and deviation
information.
7
.
Enter the transmitter frequency. Key the trans-
mitter and tune the
pass-band knobs
of
the
cavities
in
the duplexer transmit leg for
maxi-
mum power output. This
completes pass-band
adjustments.
\**rl
Tr5{r
FIGURE S.I}-DUPLEXER
ADJUSTMENT
SETUP;
RETECT NOTCH ON RECEIVE LEG
5.15.0 CAVITY AND
DUPLEXER TUNING
BANDPASS WITH
REIECT NOTCH
B.
Adjustment of
Reject notch on the
Receive leg.
l.
Connect
the
service
monitor's "RF
Inlout"
to
the
in-service duplexer as
shown
in
figure s.lz.
Disconnect
the cable at the
duplexer
receiver
port
that
comes
from
the receiver. Move
the
monitor's
"RF
Inlout"
cable
from the
duplexer
antenna
port to
the
duplexer receiver
port.
connect
a
power-rated
dummy load to
the duplexer
anten-
na
port.
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5-8
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