ENHANCED NOISE-PREDICTIVE MAXIMUM LIKELIHOOD (NPML) DATA DETECTION METHOD AND APPARATUS FOR DIRECT ACCESS STORAGE DEVICE (DASD)

摘要

A noise-predictive data detection method and apparatus (202) are provided for enhanced noise-predictive maximum-likelihood (NPML) data detection in a direct access storage device (100). A data signal from a data channel in the direct access storage device (100) is applied to a maximum-likelihood detector (222) that provides an estimated sequence signal. A noise bleacher filter (308) having a frequency response of (1 + alpha D)/(1 - beta D<2>) receives a combined estimated sequence signal and data signal and provides a noise filtered signal. A matching filter (310) and error event filter (312) receives the noise filtered signal and provides an error event filtered signal. An error correction unit (700) receives the estimated sequence signal from the maximum-likelihood detector (222) and receives the error event filtered signal and provides an error corrected estimated sequence signal.