Patent ID: 7324294
Filing Date: 2008-01-29
Classification: G11B

Abstract:
1. A magnetic recording disk drive comprising: a rotatable magnetic recording disk having a recording layer of magnetizable material, the recording layer having a plurality of generally circular data tracks, each track patterned into discrete data blocks of magnetizable material separated by nonmagnetic regions, each block being magnetizable to represent data bits; a head carrier maintained in close proximity to the disk and having a read head for generating a readback signal having positive and negative voltage peaks representing oppositely directed magnetizations from the data blocks in a data track; a read channel for generating a digital data sequence from the readback signal from the read head; and timing circuitry coupled to the read channel for generating from the readback signal from the read head a series of timing pulses for marking the bit boundaries in the digital data sequence, each pulse representing a nonmagnetic region passing the read head, said timing circuitry comprising a rectifier for rectifying the negative voltage peaks of the readback signal to positive voltage peaks, the rectified positive peaks representing the data blocks and the minima between the rectified positive peaks representing the nonmagnetic regions between the data blocks, a filter for filtering the positive peaks representing the data blocks from the rectified signal, and a peak detector for detecting said minima from the filtered signal, the peak detector output comprising said series of timing pulses.