Analysis of the accuracy of p.c.m. cascade coders

The cascade type of p.c.m. coder appears at the present time to provide the most suitable means of high-speed p.c.m. encoding. The paper describes the sources of inaccuracy in such a coder and the nature and relative gravity of the resulting errors. Criteria for error-free operation are developed in the course of an analysis based on both worst-case and statistical approaches. It emerges that the cascade coding process can be regarded as a random-walk problem, facilitating a ready method of attack. The treatment brings to light certain characteristics peculiar to the cascade coder.