Servo controller having unit for compensating error signal during dropout
AssigneePioneer Corporation
InventorsKiyoshi Tateishi, Masaki Kobayashi
Life of this patent
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Abstract
A servo control apparatus of an optical pickup includes an extractor for extracting an error signal from a read signal; an equalizer including a phase compensator for equalizing the error signal to generate a drive signal; a driver for changing the servo position of the optical pickup in response to the drive signal; a dropout detector for extracting an envelope signal from the read signal to detect a dropout of the read signal; and a controller. The controller changes an equalization characteristics of the equalizer in accordance with an amplitude of the envelope signal during the period of time when the dropout occurs or in response to an occurrence of the dropout.
Claims10
A servo control apparatus of an optical pickup for reading recorded information from a recording medium to generate a read signal, comprising:
- an error signal extractor for extracting an error signal from said read signal, said error signal indicating a deviation from a servo target value of said optical pickup;
- an equalizer including a phase compensator for equalizing said error signal by said phase compensator to generate a drive signal;
- a driver for changing the servo position of said optical pickup in response to said drive signal;
- a dropout detector for extracting an envelope signal from said read signal to detect a dropout of said read signal;
- and
- a controller for changing an equalization characteristics of said equalizer in accordance with an amplitude of the envelope signal during the period of time when said dropout occurs.
A servo control apparatus of an optical pickup for reading recorded information from a recording medium to generate a read signal, comprising:
- an error signal extractor for extracting an error signal from said read signal, said error signal indicating a deviation from a servo target value of said optical pickup;
- an equalizer including a phase compensator for equalizing said error signal by said phase compensator to generate a drive signal;
- a driver for changing the servo position of said optical pickup in response to said drive signal;
- a dropout detector for extracting an envelope signal from said read signal to detect a dropout of said read signal;
- and
- a controller for changing an equalization characteristics of said equalizer in response to an occurrence of said dropout;
- wherein said controller increases a phase margin in a predetermined frequency range of said equalizer in response to the beginning of said dropout and decreases said phase margin in response to the termination of said dropout.
A servo control apparatus of an optical pickup for reading recorded information from a recording medium to generate a read signal, comprising:
- an error signal extractor for extracting an error signal from said read signal, said error signal indicating a deviation from a servo target value of said optical pickup;
- an equalizer including a phase compensator for equalizing said error signal by said phase compensator to generate a drive signal;
- a driver for changing the servo position of said optical pickup in response to said drive signal;
- a dropout detector for extracting an envelope signal from said read signal to detect a dropout of said read signal;
- and
- a controller for changing an equalization characteristics of said equalizer in response to an occurrence of said dropout;
- wherein said controller includes a timer for measuring the elapsed time from the termination of said dropout and performs control for changing said equalization characteristics of said equalizer based on the output of said timer.
A servo control apparatus of an optical pickup for reading recorded information from a recording medium to generate a read signal, comprising:
- an error signal extractor for extracting an error signal from said read signal, said error signal indicating a deviation from a servo target value of said optical pickup;
- an equalizer including a phase compensator for equalizing said error signal by said phase compensator to generate a drive signal;
- a driver for changing the servo position of said optical pickup in response to said drive signal;
- a dropout detector for extracting an envelope signal from said read signal to detect a dropout of said read signal;
- and
- a controller for changing an equalization characteristics of said equalizer in response to an occurrence of said dropout;
- wherein said equalizer includes an integrator for integrating said error signal to generate an error integration signal and an adder for supplying an added signal of an error proportional signal which is proportional to said error signal and said error integration signal to said driver as said drive signal;
- wherein said controller performs, during the occurrence of the dropout, at least one of decreasing the error proportional signal component in said drive signal and increasing the error integration signal component to change said equalization characteristics.
Dependencies are inferred from the claim text.