A NEW TYPE OF PSK ANTI-AMBIGUITY SYSTEM FOR SATELLITE APPLICATIONS

Abstract

In coherent PCM-PSK links the problem of solving the phase ambiguity in the reconstruction of the subcarrier has been traditionally solved by making use of the knowledge of some part of the transmitted message or by employing MARK-type codes. After a brief discussion of these well-known methods a new approach is proposed which makes use of an auxiliary non-ambiguous PSK demodulator based on the estimation of the sign of the message transitions. It is shown that no particular requirements on the noise performance of this auxiliary demodulator is needed to ensure acceptable overall performance of the antiambiguity system. A particularly simple hardware implementation is indicated and experimental results are presented for cases of practical interest.