Magnetic disk drive having read channel in which low-frequency cutoff is set relatively high to cope with thermal asperity

摘要

A magnetic disk drive includes a circuit portion having transfer characteristics for determining low-frequency cutoff characteristics in a transfer line ranging from a signal output terminal P1 of a head to a branch portion P2 between a data demodulation circuit and a servo demodulation circuit, and an equalization circuit having transfer characteristics having the relation of an inverse function to low-frequency portion of the transfer characteristics between P1 and P2, disposed in the transfer line ranging from the branch portion to the servo demodulation circuit. This circuit constitution can reduce waveform distortion of servo signals at the time of reproduction and can improve the positioning accuracy of the head.