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'~-7-·3
'''JFF-THE-AIR" DUPLEX TESTING (FM/AM-120DA ONLY)
In this mode, the output of the UUT transmitter is monitored ''off-the-
air" at the FM/AM-12DDA ANT Connector (34), while the FM/AM-12.DDA offset
generator output (available at the Duplex Output Connector ( 14) or T /R
Connector [ 11)) is applied to the UUT receiver input.
jCAUTION\
DO NOT TRANSMIT INTO ANTENNA CONNECTOR (34);
RF INPUTS IN EXCESS OF D. 25 WATTS MAY CAUSE
DAMAGE TO FM/AM-1200A.
4-7-4
DUPLEX TESTING USING COMMON TRANSMIT/RECEIVE LINE (HALF DUPLEX
OPERATION FM/AM-12DDA ONLY)
When testing a duplex transceiver with a single transmit/receive 1/0
port, a common receive/transmit line is connected between the UUT RF l/0
port and the FM/AM-12DDA T/R Connector (11).
(CAUTION\
DO NOT TRANSMIT INTO DUPLEX OUTPUT CONNECTOR
(14), AS CONNECTOR IS NOT PROTECTED AGAINST RF
INPUTS ABOVE 0.25 WATTS.
[NOTE\
The offset transmitted out DUPLEX Output Con-
nector (14) is a fixed -60 dB level.
The offset transmitted out T/R Connector (11)
is a fixed -80 dB level.
The RF frequency entered in the FM/AM-1200A is
the UUT transmit frequency.
OFFSET= UUT
receive frequency minus UUT transmit frequency.
(OFFSET can bel-) negative.)
4-7-5
DUPLEX TESTING (FM/AM-12DOA ONLY)
Place MODE Selector Control (39) to "DUP" Position.
EXAMPLE:
Testing a Duplex transceiver
UUT XMT FREQ = 157.77 MHz
UUT REC FREQ = 152.51 MHz
ENTER:~ ~-~~-~~-~~-~~-~l.;:l
(UUT XMT Freq)
L
lOPS
Of'T
DVM
•
DVM
~
4 -42
02
[NOTE\
OFFSET = 152.51 MHz (UUT Rec Freq) - 157.77 MHz
(UUT XMT Freq) (OFFSET = -5.26 MHz)
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