Published in Ross, M.D., & Osborne, W.P. (1995). Quantization of signals and metrics in the decoding of 8-PSK TCM. Conference Proceedings of the 1995 IEEE Fourteenth Annual International Phoenix Conference on Computers and Communications, 1995, 607-609. doi: 10.1109/PCCC.1995.472431 ©1995 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.


The performance of rate 2/3 8-PSK Trellis Coded Modulation was investigated as a function of the numerical resolution of the metrics and signal vectors used in decoding by the Viterbi algorithm. It was found that a 16 state Ungerboeck code using 5 bit I and Q with 7 bit metrics achieved roughly the same performance as pragmatic TCM. The findings were applied to the digital logic design of a TCM decoder.