Synthesis of High Data Rate Coherent Telemetry Systems

Abstract

For high data rate telemetry (above 100 Mbits/sec) multiphase modulation effectively trades transmitter power to alleviate the RF bandwidth requirements. This paper presents a unified method of synthesizing and analyzing multiphase systems. In particular, the design of multiphase modulators and three types of coherent demodulators are discussed in detail. Included is a description of 400 Mbits/sec quadriphase system fabricated by TRW which employs direct modulation and demodulation of an 8.5 GHz carrier and a transversal filter to effect matched data filtering. This system operates within 2.5 db of theoretical performance of coherent quadriphase.