Patent ID: 6014276
Filing Date: 2000-01-11
Classification: G11B

Abstract:
A servo mark detection device for detecting a data pattern called a servo mark indicating a start position of a specific area on a data surface of a magnetic disk medium of a data surface servo scheme, comprising:synchronizing means for detecting a peak of a signal amplitude of a data pattern read by a magnetic head and outputting a synchronization data signal synchronized with a clock from a raw read data signal;first register means for sequentially storing the synchronization data signal from said synchronizing means and outputting an N-bit latch data signal;determination means for determining a frame pattern of the latch data signal from said first register means, outputting a determination data signal indicating the determination result, determining a phase shift of the latch data signal with respect to the clock, and outputting a phase correction signal indicating the determination result;control means for outputting a frame pulse signal at a predetermined clock period, outputting a frame pulse signal at a timing corrected with respect to the predetermined clock period on the basis of the phase correction signal from said determination means, and outputting a check window signal when a predetermined number of frame pulse signals are output;second register means for sequentially latching the determination data signal from said determination means in synchronism with the frame pulse signal from said control means, and outputting a servo mark data signal; andservo mark comparing means for, when the check window signal from said control means is active, comparing the servo mark signal from said second register means with a predetermined reference pattern, and outputting a servo mark detection signal.