Further results on cosets of convolutional codes with short maximum zero-run lengths

We study the maximum zero-run length, L_max, of cosets of convolutional codes, and show that an associated block subcode to a large extent determines L_max. A communication system or storage system may use a coset of a binary convolutional code for both symbol synchronization and error control. To achieve symbol synchronization, the coset must have a short maximum zero-run length, L _{(max). The shortest values of Lmax can be found in the class of convolutional codes of rate (n-r)/n for which at least one row of a minimal parity check matrix is nonpolynomial. We focus on this class}