An introduction to the PDTS (PCM/DSI Test Set) - Design principles and application in the Intelsat TDMA/DSI system

The use of the PCM/DSI Test Set (PDTS) to evaluate the performance of the DSI or DNI unit in the Intelsat TDMA system is discussed. The PDTS verifies proper functioning of DSI units and assures a means of end-to-end BER testing to confirm the correct alignment of satellite links from station to station. The PDTS is a modular system which contains three subsystems: the controller, transmitter, and receiver; the composition and functions of these subsystems are described. There are two categories of tests the PDTS performs, an operational or off-line test and a live-traffic test. An explanation of when each test would be implemented and the procedures involved is presented.