However, in many circumstances, errors occur in groups, or bursts. Parity checking of the kind just described then provides little protection. In these circumstances, a polynomial code is used. The mechanism of polynomial codes is beyond the scope of this course. We shall content ourselves with a description.
Polynomial codes work on each frame.
Additional digits are added to the end of each frame. These digits depend on the contents of the frame. The number of added digits depends on the length of the expected error burst. Typically 16 or 32 digits are added. Before transmission, each frame is divided by a generator polynomial.