AT7120 Owner Manual Rev. 1.1
– March 2009 26/76
Section 4 – IF/UHF up-converter
Module 4492
Introduction
The module 4492 performs the following basic functions:
This module translates the incoming I and Q IF carriers from the 8VSB modulator, to the desired
FCC/UHF channel.
Controls the RF output power of the exciter.
The desired channel is entered via the keypad and the LCD display in the factory. Channel changes are
not allowed by the end user.
Fig.4.1: Module 4492, RF connections.
The main features associated with this module are:
Simple conversion
Orthogonal mixing, which performs the image and LO rejections
Synthesized local oscillator via PLL, 22 bits serial fractional
Allows channel offset programming @ 1Hz resolution when using external 10MHz? reference
RF Output
Ref. 10MHz input
2 x LO sample
(Q) IF input
(I) IF input