Decoding errors in PCM systems with modal pseudoternary codes

A single transmission error can give rise to multiple errors in the decoded data and this phenomenon is described by the error multiplication factor. This factor can be used to predict the error rate in the decoded data for a given error rate in the received data. This paper describes the problem of error multiplication in the decoder of modal pseudoternary codes. In analyzing such codes it is assumed that the input data is a random, and a suitable Markov chain has been constructed to describe the coded signal. The statistical distribution of number of errors in the decoded data, due to a single transmission error, and the error multiplication factor are also evaluated. Results of computations are presented and discussed for CHDBm codes with m=2 and 3 as examples of these codes.