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NOTE
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 10 MHz (adjustable). The lmage/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
fold back region. If the generator is operated in this fold back 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.
NOTE
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.
R-2001A
DUPLEX
RF
OUTPUT
IN/OUT
FUNCTION
IUPLEX
GENER~TO~
451.500
nH:
REPEATER XMIT
FREQUENCY
REPEATED
RECEIVED FREQUENCY
ATER
REPE
RFIN
REPEATER
RF OUT
REPEATER
NEG DEVIATION
OF R EPEATEO SIGNAL
[)
s
EVIATION ALARM -
ETIING
DIJPlf/. 110N
DEV rHZ
f'ITtE~<
·:
8521-27
POS DEVIATION
.,._ OF REPEATED SIGNAL
Figure 4-5.
Duplex Generation Test Setup and CRT Display
4-14
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