Modified viterbi detector which accounts for correlated noise

Abstract

A system detects an input signal received over a plurality of time periods. The input signal corresponds to one of a plurality of states during each time period, the states being connected by branches. The input signal has a value that is changeable from one of the plurality of time periods to the next. A first merged state is detected in which the branches during a first merge time period lead to only one of the plurality of states. A metric is determined for each of the plurality of states for each time period. The metric is based on the value of the input signal during a present time period, the value of the input signal during a previous time period, and on the plurality of branches connected to the states for which the metric is being determined. The likely branch leading to each of the plurality of states is identified based on the metric determined for that state. A second merged state is detected in which the branches during a second merge time period lead to only one of the plurality of states. The value of the input signal is determined for each time period between the first and second merged states based on the likely branches leading between the first and second merged states.