Patent ID: 8457926
Filing Date: 2013-06-04
Classification: G11B

Abstract:
1. A disk protrusion detection/flatness measurement circuit comprising: a protrusion detection sensor; an amplifier circuit for amplifying a signal from the protrusion detection sensor; an A/D conversion circuit for converting a detection signal amplified by the amplifier circuit, from an analog signal to a digital signal; and a data processing circuit comprising: a band-pass filter block for filtering a digital signal received from the A/D conversion circuit with at least a predetermined bandwidth; a peak detection process block for detecting a peak value based on the signal received from the band-pass filter block and providing an output based on the detected peak value and representing a disk protrusion measurement; and an average value calculation process block for calculating an average value of the signal received from the band-pass filter block within a track or a sector of a disk and providing an output based on the calculated average value and representing a flatness measurement.