Maximum-likelihood data detection in a partial-response data channel for a direct access storage device

摘要

A method and apparatus are provided for maximum-likelihood data detection in a partial-response (PR) data channel including a head and disk assembly providing an analog signal coupled to an analog to digital converter (ADC) providing digital samples. A plurality of digital samples are received from the ADC. The received digital samples are applied to a selected first filter 402 and a selected second filter 404. The first filtered digital samples are applied to a first data detector 406, and the second filtered digital samples are applied to a second data detector 408. A predetermined parameter is identified 410, and at least one of the first and second data detectors is selected responsive to the identified predetermined parameter. The detectors may comprise partial response, adaptive, full-state or reduced-state Viterbi detectors (e.g. PR4 or EPR4 Viterbi detectors). IMAGE