User Manual

Table Of Contents
Operation RF-Orchestra!™ Transmitter Installation and Operation
5-32 6880493G02-C July 2000
Figure 5-17: Spectrum Analyzer Display With Carrier Feedthrough
CFT nulling adjusts the I and Q Offset values in the Collector DSP. The I and Q Offset are RFO
FIPS:
parameters 979 and 980, respectively.
As the temperature of the station changes, the CFT component can change. Even a properly
adjusted (nulled) transmitter must be periodically readjusted to assure that the CFT
component is kept at a minimum level.
CFT nulling can be done manually, semiautomatically, or automatically.
Manual Carrier Feedthrough Nulling
This method of nulling the carrier requires the user to enter different I and Q offset values
through the FIPS interface. This method takes the most effort on the part of the user and
contains the highest potential for error. (See RFO FIPS: parameters 979 and 980).
This method should only be used by development engineering. Semiautomatic or automatic
CFT nulling should be used.
CENTER
940.4750 MHz
Carrier Feedthrough
CENTER 940.4750MHz SPAN 100.00kHz
RES BW 1.0kHz VBW 1 kHz SWP 300 msec
ATTEN 10dB