Patent ID: 6714492
Filing Date: 2004-03-30
Classification: G11B

Abstract:
An optical disc player, comprising:a spindle controller for rotating an optical disc; a pickup for reading information on the optical disc, the pickup having a focusing actuator and a tracking actuator; an RF amplifier for detecting and amplifying a focusing error signal and a tracking error signal from information on the optical disc obtained from the pickup; a focusing servo for controlling the focusing actuator in response to the amplified focusing error signal; a tracking servo for outputting a tracking control signal in response to the amplified tracking error signal; and an eccentricity compensator for outputting a signal which compensates for the eccentricity of an optical disc in response to the output signal of the spindle controller, the amplified tracking error signal and the amplified tracking control signal, the eccentricity compensator detecting the rotation period of the optical disc, producing a plurality of pulses using the detected rotation period, detecting an eccentricity included in the amplified tracking error signal according to the plurality of generated pulses and generating a compensating signal for the detected eccentricity; wherein the eccentricity compensator comprises: a disc rotation detector for outputting a series of digital pulses every rotation of the optical disc in response to the output signal of the spindle controller, a pulse signal generator for outputting first and second pulse signals in response to the series of digital pulses, an eccentricity controller for outputting an eccentricity control signal which indicates whether the eccentricity of the optical disc is to be compensated for, an eccentricity compensator unit for outputting an eccentricity compensation signal in response to the eccentricity control signal, the first pulse signal, the second pulse signal and the amplified tracking error signal, and an adder for combining the eccentricity compensation signal with the tracking control signal and transmitting the combined result to the pickup, wherein the eccentricity compensator unit comprises: a band-pass filter for receiving the amplified tracking error signal and removing at least one of DC components and noise therefrom; an eccentricity extraction and compensation unit for extracting and compensating for an eccentricity in response to the first pulse signal, the second pulse signal, the eccentricity control signal and the output signal of the band-pass filter, and a gain/phase controller for receiving the output signal of the eccentricity extraction and compensation unit and regulating the gain of the received signal and the frequency thereof, wherein the eccentricity extraction and compensation unit comprises: a one-rotation detector for outputting a one-rotation flag signal and an eccentricity compensating selection signal in response to the first pulse signal and the eccentricity control signal, a memory controller for outputting an address signal and a read/write signal in response to the eccentricity control signal, the second pulse signal and the one-rotation flag signal, a memory for selectively storing an eccentricity error which is the output signal of the band-pass filter and outputting the stored eccentricity error in response to the second pulse signal, the address signal and the read/write signal, and an eccentricity compensation selector for selecting at least one of the eccentricity error and a predetermined reference value according to the eccentricity compensation selection signal; wherein the compensating signal automatically changes in relation to the playback speed the optical disc.