Patent ID: 6462686
Filing Date: 2002-10-08
Classification: G11B,H03M

Abstract:
A servo controller for correcting a read position of a read head that reads data recorded on a recording medium, wherein a servo section is defined on the recording medium, wherein the servo section includes a plurality of segments, the servo controller comprising:an automatic gain control (AGC) circuit for generating an amplified data signal having a predetermined amplitude from data signals that have different amplitudes and are read from the segments of the servo section, wherein the amplified data signal is generated in accordance with a predetermined AGC voltage for generating an amplified data signal having a predetermined amplitude; a filter circuit connected to the AGC circuit, wherein the filter circuit eliminates unnecessary frequency elements from the amplified data signal to generate a filtered data signal; an A/D converter connected to the filter circuit, wherein the A/D converter converts the filtered data signal to generate a digital data signal; an AGC circuit controller connected to the A/D converter, wherein the AGC circuit controller generates an AGC signal to control the gain of the AGC circuit in accordance with the digital data signal; and a D/A converter connected to the AGC circuit controller, wherein the D/A converter converts the AGC signal to an analog signal to generate an AGC voltage, which is supplied to the AGC circuit, wherein the AGC circuit controller generates the AGC signal corresponding to the next segment in accordance with an amplification ratio between the data signals read from each of the segments of the servo section before reading the next segment.