1. A method of decoding an encoded signal transmitted over a channel to determine a source data signal using a non-binary trellis with a plurality of nodes, comprising the steps of: designating a plurality of binary butterfly trellises within the non-binary trellis, wherein each ending node of the non-binary trellis has at least two binary trellises associated therewith; performing a binary butterfly operation for each designated binary butterfly trellis to determine a most favorable path metric associated with the designated binary butterfly trellises such that each ending node of the non-binary trellis will have at least two most favorable path metrics associated therewith; and comparing the at least two most favorable path metrics associated with each node in the non-binary trellis determined in said step of performing to select a survivor path for each node in the non-binary trellis.