User's Manual Part 1

AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 4 - 1/5
Section 4 – Intermediate Directional Coupler,
RF Power (1:2) Splitter & (2:1) Combiner
Module 4488
4. General Description
The readings for direct and reverse RF power transmission on the exciter drawer on the ADVANCED TV line of
transmitters are display on the frontal panel of the main control unit, module 4459.
The shown values for direct and reverse power levels are RMS values, referred to the 8VSB modulated carrier.
The directional couplers are continuously delivering a DC voltage proportional to the each kind of power level.
Fig.4.1: Module 4488 - Intermediate Directional Coupler
The directional coupler is based on a 50ȍ coaxial transmission line. By coupling, two other lines collect samples
of the RF signal to be detected, DC converted, amplified and delivered to the MCU that read, interpret, process
and display the results.