Abstract: 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, 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 reduce the size of the measurement circuit. In the protrusion detection/flatness measurement circuit, 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, peak detection and average value calculation processes are applied in parallel to the obtained digital signal. Thus, pass/fail decision of the disk can be made based on the detected peak and average values.

Abstract: In the present invention, an inspection area for sampled defect data is set which has a predetermined width in the radial direction of a magnetic disk and a length round the circle of the magnetic disk in the circumferential direction thereof or a predetermined length in the circumferential direction thereof, and while limiting the defect data in the inspection area and shifting a narrow and long search frame within the area, continuing defects in the region of the search frame are followed up and detected, thereby, only curved line shaped continuing defects having comparatively large curvature near to the circle of the magnetic disk are selectively detected and acquired as circle shaped defects.

Abstract: 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, 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 reduce the size of the measurement circuit. In the protrusion detection/flatness measurement circuit, 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, peak detection and average value calculation processes are applied in parallel to the obtained digital signal. Thus, pass/fail decision of the disk can be made based on the detected peak and average values.

Abstract: A power circuit is disclosed which is connected to a power source supplying different currents. The power circuit supplying driving power from the power source to a load includes a switching unit configured to switch the driving power supplied to the load in response to an external switching signal.

Abstract: In the present invention, an inspection area for sampled defect data is set which has a predetermined width in the radial direction of a magnetic disk and a length round the circle of the magnetic disk in the circumferential direction thereof or a predetermined length in the circumferential direction thereof, and while limiting the defect data in the inspection area and shifting a narrow and long search frame within the area, continuing defects in the region of the search frame are followed up and detected, thereby, only curved line shaped continuing defects having comparatively large curvature near to the circle of the magnetic disk are selectively detected and acquired as circle shaped defects.

Abstract: A power circuit is disclosed which is connected to a power source supplying different currents. The power circuit supplying driving power from the power source to a load includes a switching unit configured to switch the driving power supplied to the load in response to an external switching signal.