An (n, k) block code in which every codeword can be separated into k information symbols and (n—k) check symbols. The information symbols are identical with those of the source message before encoding. Thus the process of encoding a systematic code involves the insertion of (n—k) check symbols into (i.e. among, before, or, most usually, after) the information symbols. The insertion positions must be the same for all the codewords in the code. Every linear code can be arranged to be systematic.