Servo processor receiving photodetector signals
View Patent ↗A digital servo method for an optical disk drive includes receiving low-pass filtered and gain-adjusted versions of photodetector output signals resulting from an illumination of an optical disk. Versions of the photodetector signals are digitized to produce digital signals. A focus control signal is determined through at least one servo algorithm in a digital signal processor based on a focus error determined from the digital signals. Alternatively, a tracking control signal is determined through at least one servo algorithm in the digital signal processor based on a tracking error determined from the digital signals. An optical disk drive includes an analog-to-digital converter configured to convert low-pass filtered and gain-adjusted versions of photodetector output signals into at least one digital signal and the digital signal processor.
1. A digital servo method for an optical disk drive, comprising:
receiving low-pass filtered and gain-adjusted versions of photodetector output signals resulting from an illumination of an optical disk;
digitizing versions of the photodetector signals to produce digital signals; and
determining, through at least one servo algorithm in a digital signal processor, a focus control signal based on a focus error determined from the digital signals, wherein the digital signal processor is specialized for processing digital signals.
2. A digital servo method for an optical disk drive, comprising:
receiving low-pass filtered and gain-adjusted versions of photodetector output signals resulting from an illumination of an optical disk;
digitizing versions of the photodetector signals to produce digital signals; and
determining, through at least one servo algorithm in a digital signal processor, a tracking control signal based on a tracking error determined from the digital signals, wherein the digital signal processor is specialized for processing digital signals.
3. A digital servo method for an optical disk drive, comprising:
low-pass filtering and gain-adjusting versions of photodetector output signals resulting from an illumination of an optical disk;
digitizing versions of the photodetector signals to produce digital signals; and
determining, through at least one servo algorithm in a digital signal processor, a focus control signal based on a focus error determined from the digital signals, wherein the digital signal processor is specialized for processing digital signals.
4. The digital servo method of claim 3 , comprising:
adjusting one or more gain values for gain-adjusting one or more versions of the photodetector output signals based on a calculation performed by the digital signal processor.
5. The digital servo method of claim 3 , comprising:
determining, by the digital signal processor, one or more gain values for gain-adjusting one or more versions of the photodetector output signals.
6. The digital servo method of claim 5 , comprising:
gain-adjusting the one or more versions of the photodetector output signals based on the determined one or more gain values.
7. The digital servo method of claim 1 , comprising:
driving a focus actuator based on the focus control signal.
8. A digital servo method for an optical disk drive, comprising:
low-pass filtering and gain-adjusting versions of photodetector output signals resulting from an illumination of an optical disk;
digitizing versions of the photodetector signals to produce digital signals; and
determining, through at least one servo algorithm in a digital signal processor, a tracking control signal based on a tracking error determined from the digital signals, wherein the digital signal processor is specialized for processing digital signals.
9. The digital servo method of claim 8 , comprising:
adjusting one or more gain values for gain-adjusting one or more versions of the photodetector output signals based on a calculation performed by the digital signal processor.
10. The digital servo method of claim 8 , comprising:
determining, by the digital signal processor, one or more gain values for gain-adjusting one or more versions of the photodetector output signals.
11. The digital servo method of claim 10 , comprising:
gain-adjusting the one or more versions of the photodetector output signals based on the determined one or more gain values.
12. The digital servo method of claim 8 , comprising:
driving a tracking actuator based on the tracking control signal.
13. An optical disk drive, comprising:
an analog-to-digital converter configured to convert low-pass filtered and gain-adjusted versions of photodetector output signals into at least one digital signal; and
a digital signal processor configured to determine a focus error from the at least one digital signal and to determine, through at least one servo algorithm, a focus control signal from the focus error, wherein the digital signal processor is specialized for processing digital signals.
14. An optical disk drive, comprising:
an analog-to-digital converter configured to convert low-pass filtered and gain-adjusted versions of photodetector output signals into at least one digital signal; and
a digital signal processor configured to determine a tracking error from the at least one digital signal and to determine, through at least one servo algorithm, a tracking control signal from the tracking error, wherein the digital signal processor is specialized for processing digital signals.
15. An optical disk drive, comprising:
at least one low pass filter;
at least one amplifier;
an analog-to-digital converter configured to convert, into at least one digital signal, versions of photodetector output signals low-pass filtered by the at least one low pass filter and gain-adjusted by the at least one amplifier; and
a digital signal processor configured to determine a focus error from the at least one digital signal and to determine, through at least one servo algorithm, a focus control signal from the focus error, wherein the digital signal processor is specialized for processing digital signals.
16. The optical disk drive of claim 15 , wherein the digital signal processor is configured to determine one or more gain values for gain-adjusting one or more versions of the photodetector output signals.
17. The optical disk drive of claim 15 , comprising:
a plurality of photodetectors configured to provide, to the digital signal processor, photodetector output signals resulting from an illumination of an optical disk.
18. The optical disk drive of claim 15 , comprising:
a driver configured to receive, from the digital signal processor, the focus control signal and to drive a focus actuator based on the focus control signal.
19. An optical disk drive, comprising:
at least one low pass filter;
at least one amplifier;
an analog-to-digital converter configured to convert, into at least one digital signal, versions of photodetector output signals low-pass filtered by the at least one low pass filter and gain-adjusted by the at least one amplifier; and
a digital signal processor configured to determine a tracking error from the at least one digital signal and to determine, through at least one servo algorithm, a tracking control signal from the tracking error, wherein the digital signal processor is specialized for processing digital signals.
20. The optical disk drive of claim 19 , wherein the digital signal processor is configured to determine one or more gain values for gain-adjusting one or more versions of the photodetector output signals.
21. The optical disk drive of claim 19 , comprising:
a plurality of photodetectors configured to provide, to the digital signal processor, photodetector output signals resulting from an illumination of an optical disk.
22. The optical disk drive of claim 19 , comprising:
a driver configured to receive, from the digital signal processor, the tracking control signal and to drive a tracking actuator based on the tracking control signal.
23. A non-transitory computer readable medium storing a computer program, executable by a machine, for a digital servo method for an optical disk drive, the computer program comprising executable instructions for:
low-pass filtering and gain-adjusting versions of photodetector output signals resulting from an illumination of an optical disk;
digitizing versions of the photodetector signals to produce digital signals; and
determining, through at least one servo algorithm in a digital signal processor, a focus control signal based on a focus error determined from the digital signals, wherein the digital signal processor is specialized for processing digital signals.
24. A non-transitory computer readable medium storing a computer program, executable by a machine, for a digital servo method for an optical disk drive, the computer program comprising executable instructions for:
low-pass filtering and gain-adjusting versions of photodetector output signals resulting from an illumination of an optical disk;
digitizing versions of the photodetector signals to produce digital signals; and
determining, through at least one servo algorithm in a digital signal processor, a tracking control signal based on a tracking error determined from the digital signals, wherein the digital signal processor is specialized for processing digital signals.
25. A non-transitory computer readable medium storing a computer program, executable by a machine, for a digital servo method for an optical disk drive, the computer program comprising executable instructions for:
receiving low-pass filtered and gain-adjusted versions of photodetector output signals resulting from an illumination of an optical disk;
digitizing versions of the photodetector signals to produce digital signals; and
determining, through at least one servo algorithm in a digital signal processor, a focus control signal based on a focus error determined from the digital signals, wherein the digital signal processor is specialized for processing digital signals.
26. The computer program of claim 25 , comprising executable instructions for:
adjusting one or more gain values for gain-adjusting one or more versions of the photodetector output signals based on a calculation performed by the digital signal processor.
27. The computer program of claim 25 , comprising executable instructions for:
determining, by the digital signal processor, one or more gain values for gain-adjusting one or more versions of the photodetector output signals.
28. The computer program of claim 27 , comprising executable instructions for:
gain-adjusting the one or more versions of the photodetector output signals based on the determined one or more gain values.
29. The computer program of claim 25 , comprising executable instructions for:
driving a focus actuator based on the focus control signal.
30. A non-transitory computer readable medium storing a computer program, executable by a machine, for a digital servo method for an optical disk drive, the computer program comprising executable instructions for:
receiving low-pass filtered and gain-adjusted versions of photodetector output signals resulting from an illumination of an optical disk;
digitizing versions of the photodetector signals to produce digital signals; and
determining, through at least one servo algorithm in a digital signal processor, a tracking control signal based on a tracking error determined from the digital signals, wherein the digital signal processor is specialized for processing digital signals.
31. The computer program of claim 30 , comprising executable instructions for:
adjusting one or more gain values for gain-adjusting one or more versions of the photodetector output signals based on a calculation performed by the digital signal processor.
32. The computer program of claim 30 , comprising executable instructions for:
determining, by the digital signal processor, one or more gain values for gain-adjusting one or more versions of the photodetector output signals.
33. The computer program of claim 32 , comprising executable instructions for:
gain-adjusting the one or more versions of the photodetector output signals based on the determined one or more gain values.
34. The computer program of claim 30 , comprising executable instructions for:
driving a tracking actuator based on the tracking control signal.