MUTUAL INTERFERENCE WITH DUAL CHANNEL OPERATION

Abstract

The Communications Interface Equipment is a multi-link communication subsystem designed to augment the command and telemetry capabilities of the Space Shuttle and its payloads. One link consists of two PSK channels which are frequency division multiplexed. In each channel the data can be at one of several possible data rates and either NRZ or Bi0/ encoded. Simultaneous operation of the two channels causes a performance degradation to each due to mutual interference. The amount of degradation is a function of modulation formats, data rates, relative channel powers, probability of error and bandpass filter characteristics. Approximations for the degradation are derived, and the performance sensitivity to the various parameters is demonstrated.