Duplex Generation - Motorola R-2001A Service Manual

The RF protect circuit may trip if generator is run at full power output without having
a 50-ohm load connected.
4-9. DUPLEX GENERATION. When operating in the duplex generate mode the offset frequency can be set
to either 45 MHz or 0 to 10MHz (adjustable). The Image/Dplx switch sets the offset frequency above (high) or
below (low) the monitored frequency. When offset is in the 0 to 10 MHz range, the control range may include a
foldback region. If the generator is operated in this foldback area erroneous frequency output indications can
be given. Avoid areas where backward indication or a jittering display of the offset frequency are incurred. The
following is an example of the duplex generator being used to setup repeater levels.
a. Connect DUPLEX GEN output to repeater receiver antenna input and repeater transmitter signal
sample to RF In/Out connector. The Duplex Gen Output level is fixed at -30 dBm nominal.
b. Set FUNCTION switch to Gen and DISPLAY to Duplex Gen.
c. Select Duplex Monitor frequency (repeater transmit frequency) from memory table or enter directly
from keyboard.
d. Set DUPLEX GENERATOR frequency to repeater receiver frequency.
e. Adjust PL and test tone deviation to desired level on display.
f. Set FUNCTION switch to Monitor and measure the deviation of the repeated signal.
Switch function to power monitor and connect repeater transmitter (under 125
watts) directly to the RF In/Out connector to read power and frequency error, as
well.
DUPLEX RF
OUTPUT IN/OUT
? ?
REPEATER REPEATER
RF IN . RF OUT
R-2001A
FUNCTION -
NEG DEVIATION
OF REPEATEO SIGNAL '
OEVIATION ALARM
SETTING
Figure 4-5. Duplex Generation Test Setup and CRT Display
NOTE
NOTE
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(UPLtX CENEIiflTDf 4 5 1 . 6 0 0
1UPLE.1 HDH
'•.c;. TIE'.I KHZ
c
£ V ft L fi F 11 C' , 0 • M :
4-14
REPEATER XMIT
FREQUENCY
. REPEATED
11H:
RECEIVED FREQUENCY
POS DEVIATION
' OF REPEATED SIGNAL
8521-27