A decoder includes at least one programming input for a plurality of programmable reduced-state trellis parameters. A programmable device is connected to the at least one programming input and implements a reduced-state maximum likelihood decoder that is operable for processing a continuous phase modulated (CPM) signal and returning up to N bits that were transmitted based on a maximum likelihood and current winning super-state and corresponding survivor full-state. The programmable device calculates the path metrics for every super-state and determines a best path based on the reduced-state trellis parameters.