The Effects of the Reference Carrier Phase Error on a High-speed Data Communication System Employing a Viterbi Detector

A Viterbi detector for high-speed data transmission over a voice-band telephone channel is receiving an increasing amount of attention recently. On the other hand amplitude modulation and coherent detection are employed in a high-speed data communication system for the purpose of using a frequency band efficiently. This paper describes the effects of the reference carrier phase error on the high-speed data communication system employing the Viterbi detector, First the relation between the phase error and the effective signal-to-noise ratio (an evaluation function of the system) is derived. Secondly further analysis is performed regarding a SSB-AM (single-sideband amplitude modulation) system. Numerical results indicate that the performance of the data communication system is degraded substantially due to the reference carrier phase errorr. And it was also shown that the allowable phase error in a SSB-AM system with data rates of 12,000 bits/s is about 2 degrees