Abstract: An improved read channel for storage and communication application particularly useful in optical storage applications. The improved read channel includes a Viterbi sequence detector tuned to a preferred partial response target well suited to sensing of pulses in the waveforms typical of optical storage read heads. In particular, the read channel of the present invention implements pulse and sequence detection for a partial response target having a spectral null at the Nyquist frequency and having a relative minimum between zero and the Nyquist frequency. In other words, the partial response target of the improved read channel is not a monotonic decreasing function between zero and the Nyquist frequency as is known in present read channels. More specifically, in the preferred embodiment, the partial response target of the read channel includes a spectral null at the Nyquist frequency and another spectral null at half the Nyquist frequency.