Multiple-word correcting convolutional codes

Two classes of multiple-word correcting convolutional encoders are defined and analyzed. We obtain some conditions for these encoders to be noncatastrophic, and we describe ways to check the (word) minimum distance of the generated codes. The first class can easily be analyzed by algebraic means, but the redundancy of the corresponding codes is not arbitrarily iow. The codes generated by the second class of encoders may have a lower redundancy, but their analysis requires the use of a computer program.