Viterbi decoder for decoding a received sequence of data symbols which are
coded using a predetermined coding instruction is provided. The Viterbi
decoder includes a branch metric calculation circuit for calculation of
branch metrics for the received sequence of coded data symbols. The
Viterbi decoder includes a path metric calculation circuit for
calculation of path metrics as a function of the branch metrics and the
coding instruction, with the calculated path metrics in each case being
compared with an adjustable decision threshold value in order to produce
an associated logic validity value. The Viterbi decoder also includes a
selection circuit which temporarily stores those path metrics whose
validity value is logic high in a memory, and selects from the
temporarily stored path metrics that path with the optimum path metric.