1. A tracking error signal calculation circuit for calculating a tracking error signal in an optical disc apparatus having a light receiving means as herein described for outputting first and second received light detection signals from regions located at the two sides of the center of a track of a disc-like recording medium, characterized in that the said circuit comprising: a first calculation circuit for detecting a peak of the first received light detection signal from the light receiving means and subtracting a signal obtained by multiplying a first coefficient with the peak from the first received light detection signal to calculate a first calculation signal; a first coefficient changing circuit for changing the first coefficient, wherein the first coefficient changing circuit has a circuit for changing the first coefficient depending upon a frequency of the first received light detection signal; a second calculation circuit for detecting a peak of the second received light detection signal from the light receiving means and subtracting a signal obtained by multiplying a second coefficient with the peak from the second received light detection signal to calculate a second calculation signal; and a third calculation circuit for subtracting the second calculation signal from the first calculation signal to calculate the tracking error signal.

2. A tracking error signal calculation circuit as claimed in claim 1, comprises a second coefficient changing circuit for changing the second coefficient.

3. A tracking error signal calculation circuit as claimed in claim 2, wherein the second coefficient changing circuit for changing the second coefficient depending upon a frequency of the second received light detection signal.

4. An optical disc apparatus as claimed in claim 1, comprising: a disc recording medium, an optical pick-up, a signal calculation circuit provided outside of the optical pick-up, and a tracking controlling means (110) for performing position control of the optical pick-up to a predetermined track, wherein said optical pick-up includes: an optical means preferably a laser diode for emitting a converged beam to a recording surface of the disc recording medium, a light receiving means preferably photodiode for receiving a returned light from the recording surface of the disc recording medium from regions located at two sides of the center of a track of the disc recording medium and outputting first and second received light detection signals, a first calculation circuit for detecting a peak of the first received light detection signal from the light receiving means and subtracting a signal obtained by multiplying a first coefficient with the peak from the first received light detection signal to calculate the first calculation signal, and a second calculation circuit for detecting a peak of the second received light detection signal from the light receiving means and subtracting a signal obtained by multiplying a second coefficient to the peak from the second received light detection signal to calculate the second calculation signal; wherein the signal calculation circuit has a third calculation circuit for subtracting the second calculation signal from the first calculation signal to calculate a tracking error signal, wherein the signal calculation circuit has a coefficient changing circuit for changing the first coefficient and outputs the first calculation signal operated on by the changed first coefficient to the third calculation circuit, and wherein the coefficient changing circuit has a circuit for changing the first coefficient in response to a frequency of the first received light detection signal.

5. An optical disc apparatus as claimed in claim 4, wherein the signal calculation circuit has a second coefficient changing circuit for changing the second coefficient and outputs the second calculation signal operated on by the changed second coefficient to the third calculation circuit.

6. An optical disc apparatus as claimed in claim 4, wherein: the light receiving means has two light receiving elements provided along a light axis of the returned light; the first light receiving element is provided so as to receive the returned light from the recording surface of the disc recording medium from the regions located at the two sides of the center of the track of the disc recording medium and output the first and second signals; the second light receiving element is provided so as to receive the returned light from the recording surface of the disc recording medium from the regions located at the two sides of to the center of the track of the disc recording medium and output third and fourth signals in an inverse phase relationship from corresponding regions of the light axis; and the light receiving means adds the first signal and the fourth signal in the same phase relationship, outputs the same as the first received light detection signal, adds the second signal and the third signal which are in the inverse phase relationship to the first received light detection signal, but in the same phase relationship as each other, and outputs the same as the second received light detection signal.

7. A tracking control apparatus in an optical disc apparatus as claimed in claim 1, for reproducing a signal from and/or for recording a signal to a disk-like recording medium, said tracking control apparatus comprising: a light collection means preferably an object lens for collecting a light beam emitted from a light source toward the disc-like recording medium; a light receiving means, comprising first and second divided light receiving element groups, for receiving a fight beam reflected at the disclike recording medium to output first and second light received detection signals corresponding to regions positioned at both sides with respect to a signal track center of the disc-like recording medium; a first calculation circuit for calculating a first calculation signal from the first received fight detection signal detected at the fight receiving means by using a first coefficient; a second calculation circuit for calculating a second calculation signal from the second received light detection signal detected at the fight receiving means by using a second coefficient; a coefficient changing circuit for changing the first and second coefficients, wherein the coefficient changing means comprises a circuit for changing the first and second coefficients in response to frequencies of the first and second received light detection signals; a third calculation circuit for calculating a tracking error signal from the first and second calculation signals; and a tracking driver circuit for tracking-servo-controlling the light collection means by using the tracking error signal calculated at the third calculation means.

8. A tracking control apparatus as claimed in claim 7, wherein the fight collection means forms a single light spot of the fight beam on the disc-like recording medium.

9. A tracking control apparatus as claimed in claim 7, wherein the object lens forms a single light spot of the light beam on the disc-like recording medium.

10. A method for calculating the tracking error signal in an optical disc apparatus as claimed in claim 1 having a light receiving means for outputting first and second received light detection signals from regions located at two sides of a center of a track of a disc-like recording medium, including the steps of: detecting a peak of the first received light detection signal from the first received light detection signal and subtracting the signal obtained by multiplying a first coefficient with the peak from the first received light detection signal to calculate a first calculation signal; detecting a peak of the second received light detection signal from the second received light detection signal and subtracting the signal obtained by multiplying a second coefficient with the peak from the second received light detection signal to calculate a second calculation signal; performing a calculation on at least one of the first calculation signal and the second calculation signal so that at least one of the first coefficient and the second coefficient changes in response to a frequency band of at least one of the first received light detection signal and the second received light detection signal; and generating the tracking error signal by subtracting the second calculation signal from the first calculation signal.

11. The method as claimed in claim 10, wherein the step of performing comprises the steps of: detecting the frequency band of the first received light detection signal; and changing the first coefficient in response to the detected frequency band.

12. The method as claimed in claim 11, comprising the steps of: detecting the frequency band of the second received light detection signal; and changing the second coefficient in response to the detected frequency band of the second received light detection signal.

13. The method as claimed in claim 12, wherein the step of performing comprises the steps of: detecting the frequency band of the second received light detection signal; and changing the second coefficient in response to the detected frequency band.

14. A tracking error signal calculation circuit substantially as hereinbefore described with reference to the accompanying drawings.

15. An optical disc apparatus substantially as hereinbefore described with reference to the accompanying drawings.

DESCRIPTION (COMPLETE) OCR NOT PREPARE
DUE TO PRINT PROBLEM

WE CLAIM:-
1. A tracking error signal calculation circuit for calculating a tracking error signal in an optical disc apparatus having a light receiving means as herein described for outputting first and second received light detection signals from regions located at the two sides of the center of a track of a disc-like recording medium, characterized in that the said circuit comprising:
a first calculation circuit for detecting a peak of the first received light detection signal from the light receiving means and subtracting a signal obtained by multiplying a first coefficient with the peak from the first received light detection signal to calculate a first calculation signal;
a first coefficient changing circuit for changing the first coefficient, wherein the first coefficient changing circuit has a circuit for changing the first coefficient depending upon a frequency of the first received light detection signal;
a second calculation circuit for detecting a peak of the second received light detection signal from the light receiving means and subtracting a signal obtained by multiplying a second coefficient with the peak from the second received light detection signal to calculate a second calculation signal; and
a third calculation circuit for subtracting the second calculation signal from the first calculation signal to calculate the tracking error signal.
2. A tracking error signal calculation circuit as claimed in claim 1, comprises a second coefficient changing circuit for changing the second coefficient.
3. A tracking error signal calculation circuit as claimed in claim 2, wherein the second coefficient changing circuit for changing the second coefficient depending upon a frequency of the second received light detection signal.
4. An optical disc apparatus as claimed in claim 1, comprising: a disc recording medium,
an optical pick-up,
a signal calculation circuit provided outside of the optical pick-up, and
a tracking controlling means (110) for performing position control of the optical pick-up to a predetermined track, wherein said optical pick-up includes:
an optical means preferably a laser diode for emitting a converged beam to a recording surface of the disc recording medium,
a light receiving means preferably photodiode for receiving a returned light from the recording surface of the disc recording medium from regions located at two sides of the center of a track of the disc recording medium and outputting first and second received light detection signals,
a first calculation circuit for detecting a peak of the first received light detection signal from the light receiving means and subtracting a signal obtained by multiplying a first coefficient with the peak from the first received light detection signal to calculate the first calculation signal, and
a second calculation circuit for detecting a peak of the second received light detection signal from the light receiving means and subtracting a signal obtained by multiplying a second coefficient to the peak from the second received light detection signal to calculate the second calculation signal;
wherein the signal calculation circuit has a third calculation circuit for subtracting the second calculation signal from the first calculation signal to calculate a tracking error signal,
wherein the signal calculation circuit has a coefficient changing circuit for changing the first coefficient and outputs the first calculation signal operated on by the changed first coefficient to the third calculation circuit, and
wherein the coefficient changing circuit has a circuit for changing the first coefficient in response to a frequency of the first received light detection signal.
5. An optical disc apparatus as claimed in claim 4, wherein the signal calculation circuit has a second coefficient changing circuit for changing the second coefficient and outputs the second calculation signal operated on by the changed second coefficient to the third calculation circuit.
6. An optical disc apparatus as claimed in claim 4, wherein:
the light receiving means has two light receiving elements provided along a light axis of the returned light;
the first light receiving element is provided so as to receive the returned light from the recording surface of the disc recording medium from the regions located at the two sides of the center of the track of the disc recording medium and output the first and second signals;
the second light receiving element is provided so as to receive the returned light from the recording surface of the disc recording medium from the regions located at the two sides of to the center of the track of the disc recording medium and output third and fourth signals in an inverse phase relationship from corresponding regions of the light axis; and
the light receiving means adds the first signal and the fourth signal in the same phase relationship, outputs the same as the first received light detection signal, adds the second signal and the third signal which are in the inverse phase relationship to the first received light detection signal, but in the same phase relationship as each other, and outputs the same as the second received light detection signal.
7. A tracking control apparatus in an optical disc apparatus as claimed in claim 1, for reproducing a signal from and/or for recording a signal to a disk-like recording medium, said tracking control apparatus comprising:
a light collection means preferably an object lens for collecting a light beam emitted from a light source toward the disc-like recording medium;
a light receiving means, comprising first and second divided light receiving element groups, for receiving a fight beam reflected at the disclike recording medium to output first and second light received detection signals corresponding to regions positioned at both sides with respect to a signal track center of the disc-like recording medium;
a first calculation circuit for calculating a first calculation signal from the first received fight detection signal detected at the fight receiving means by using a first coefficient;
a second calculation circuit for calculating a second calculation signal from the second received light detection signal detected at the fight receiving means by using a second coefficient;
a coefficient changing circuit for changing the first and second coefficients, wherein the coefficient changing means comprises a circuit for changing the first and second coefficients in response to frequencies of the first and second received light detection signals;
a third calculation circuit for calculating a tracking error signal from the first and second calculation signals; and
a tracking driver circuit for tracking-servo-controlling the light collection means by using the tracking error signal calculated at the third calculation means.
8. A tracking control apparatus as claimed in claim 7, wherein the fight collection means forms a single light spot of the fight beam on the disc-like recording medium.
9. A tracking control apparatus as claimed in claim 7, wherein the object lens forms a single light spot of the light beam on the disc-like recording medium.
10. A method for calculating the tracking error signal in an optical disc apparatus as claimed in claim 1 having a light receiving means for outputting first and second received light detection signals from regions located at two sides of a center of a track of a disc-like recording medium, including the steps of:
detecting a peak of the first received light detection signal from the first received light detection signal and subtracting the signal obtained by multiplying a first coefficient with the peak from the first received light detection signal to calculate a first calculation signal;
detecting a peak of the second received light detection signal from the second received light detection signal and subtracting the signal obtained by multiplying a second coefficient with the peak from the second received light detection signal to calculate a second calculation signal;
performing a calculation on at least one of the first calculation signal and the second calculation signal so that at least one of the first coefficient and the second coefficient changes in response to a frequency band of at least one of the first received light detection signal and the second received light detection signal; and
generating the tracking error signal by subtracting the second calculation signal from the first calculation signal.
11. The method as claimed in claim 10, wherein the step of performing
comprises the steps of:
detecting the frequency band of the first received light detection signal; and
changing the first coefficient in response to the detected frequency band.
12. The method as claimed in claim 11, comprising the steps of:
detecting the frequency band of the second received light detection
signal; and
changing the second coefficient in response to the detected frequency band of the second received light detection signal.
13. The method as claimed in claim 12, wherein the step of performing
comprises the steps of:
detecting the frequency band of the second received light detection signal; and
changing the second coefficient in response to the detected frequency band.
14. A tracking error signal calculation circuit substantially as hereinbefore described with reference to the accompanying drawings.
15. An optical disc apparatus substantially as hereinbefore described with reference to the accompanying drawings.