Error correcting means for digital transmission systems

Bursts of errors in convolutionally coded messages are corrected by a decoder in which a parity checking circuit determines whether selected syndrome digits which lie within the constraint length of the code form a codeword in a linear block code having as its codewords the set of all patterns of said selected syndrome digits that are consistent with any error burst pattern confined to the beginning of said constraint length and upon the presence of such a codeword, error detecting and correction circuitry becomes operative.