A systematic (12,8) code for correcting single errors and detecting adjacent errors

A parity check matrix is given for a systematic (12,8) binary code which connects all single errors and detects eight of the nine double adjacent errors within any of the three 4-b nibbles. It is shown that no (12,8) binary systematic parity check code can correct all 12 single errors and simultaneously detect all nine double adjacent errors within 4-b nibbles. A (12,8) binary systematic parity check code is given that corrects all 12 single errors and simultaneously detects eight of the nine double adjacent errors within 4-b nibbles.<>