Some important aspects of a series of concatenated codes subjected to matrix type-

codes are investigated. Concatenated matrix codes and the concatenated quadratic residue codes especially are emphasized. An analysis of the error patterns, which can be corrected with the matrix coding, also is given. These codes are suitable for compound channels with memory (i.e., channels on which burst, cluster, and random errors occur). Explicit formulas are given for the number of bursts, cluster, and random errors that can be corrected with these codes. Decoding schemes and techniques for studying error propagation in the proposed codes are given. In particular a new decoding algorithm for a concatenated matrix code is given. The performance of coding and decoding schemes of the various types of concatenated codes can be tested in practice.