A modified Viterbi algorithm, that integrates decision feedback equalization (DFE), is disclosed. The modified algorithm may be used especially for rate ½ coded transmissions through additive noise channels, where the additive noise is one-tap filtered noise. Each state in the presently-disclosed trellis holds an aggregate error and an aggregate weight of the winner path terminating at that state. Each branch of the trellis carries one or more aggregate errors, where each of the aggregate errors includes a contribution from the aggregate error of the branch's source state as well as a contribution from the difference between an expected symbol of the branch and a corresponding received symbol.