1. A pattern recognition system comprising: a controller having at least one input receiving a test frame sequence and a plurality of signal frames to be searched for matches to the test frame sequence, wherein the controller: identifies as potential matches each sequence of frames within the plurality of signal frames having a frame with an energy magnitude that is within a predetermined difference of a local maximum energy magnitude for frames within the test frame sequence; and compares total energy for each potential match frame sequence to total energy of the test frame sequence.