It is known that multiple symbol differential detection(MSDD) has very high complexity,which is exponential with block length of N This paper presented an improved multiple differential feedback detection(IMDFD) algorithm,which not only has low computation complexity,but also can solve the problems of error propagation of MDFD algorithm and performance degradation at low signal-noise ratio.

This paper presents the basic principles of multi-symbol-detector(MSD) and turbo product codes(TPC),and gives the performance curves from the simulation and experiment.

This paper proposes a PCM/FM telemetry system with LDPC and MSD techniques and investigates the performances.

In order to solve the threshold problem existed in the rocket telemetry signal\'s demodulation with PCM-FM noncoherent demodulation technology which is applied in the shipborne TT&C equipments\' PCM-FM telemetry system,the MSD technology and its application in the PCM-FM system are analyzed.

Aiming at this problem,a modified multi-symbol algorithm is presented.

A numerical method for calculating truncated union bound of symbol error rate (SER) is presented for maximum-like- lihood (ML) multiple symbol differential detection (MSDD) over continuous channel in unitary space-time modulation systems.