Viterbi decoding method and circuit therefor

A Viterbi decoding method and a circuit therefor are provided, for demodulating a reproduced signal from a magnetic recording/reproducing apparatus. According to the Viterbi decoding method, a reproduced signal whose waveform is equalized by an equalizer is input and positive and negative peak data are obtained by two comparators whose thresholds are interlocked. Then, the data is divided by a predetermined time to be grouped. After Viterbi-decoding the grouped data in the reverse direction, final decoded data of the present group and initial decoded data of the next group are concatenated. The Viterbi decoding circuit has simple structure in which a shift register is adopted as a major constituent, without an analog-to-digital converter and microprocessor.