Projection detection degree of even measuring circuit of disk and glide tester of disk

摘要

The present invention relates to a disk protrusion detection/flatness measurement circuit and a disk glide tester, in which protrusion detection and average value calculation can be performed without switching signal processing circuits of two systems and one for the protrusion detection of a disk and the other for the average value calculation with respect to a track or a sector of the disk. This also makes it possible to reduction the size of the measurement circuit. In the protrusion detection/flatness measurement circuit and a signal from a protrusion detection sensor is amplified and converted from an analog signal to a digital signal. The signal passes through a band-pass filter to obtain a digital signal with a predetermined bandwidth. Then and peak detection and average value calculation processes are applied in parallel to the obtained digital signal. Thus and pass/fail decision of the disk can be made based ON the detected peak and average values.