Abstract: An optical disk drive and a digital servo method for the optical disk drive includes controlling functions of the optical disk drive with a microprocessor. Low-pass filtered and gain-adjusted versions of photodetector output signals resulting from an illumination of an optical disk are received. Versions of the photodetector signals are digitized to produce digital signals. A focus control signal is determined through at least one servo algorithm executed by 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 executed by the digital signal processor based on a tracking error determined from the digital signals. The digital signal processor has a specialized structure and arrangement for processing digital signals at a higher speed than the microprocessor.

Abstract: 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.

Abstract: A servo processor for an optical disk drive is provided that includes: an analog-to-digital converter for converting versions of photodetector output signals into digital signals; and a digital signal processor configured to receive the digital signals, the digital signal processor being further configured to determine a focus error signal (FES) and a tracking error signal (TES) from the digital signals, the digital signal processor being further configured to process TES and FES through servo algorithms to produce tracking and focus control signals.

Abstract: A focus servo system for an optical disk drive includes an optical pick-up unit comprising at least one photodetector. At least one analog to digital converter is configured to digitize signals received from the at least one photodetector. At least one processor is configured to execute a digital servo algorithm to process the versions of the digitized signals to calculate a focus error signal (FES) from the versions of the digitized signals and to indicate a focus open condition based on the FES and the versions of the digitized signals.

Abstract: A servo processor for an optical disk drive is provided that includes: an analog-to-digital converter for converting versions of photodetector output signals into digital signals; and a digital signal processor configured to receive the digital signals, the digital signal processor being further configured to determine a focus error signal (FES) and a tracking error signal (TES) from the digital signals, the digital signal processor being further configured to process TES and FES through servo algorithms to produce tracking and focus control signals.

Abstract: A focus servo system for an optical disk drive includes an optical pick-up unit comprising at least one photodetector. At least one analog to digital converter is configured to digitize signals received from the at least one photodetector. At least one processor is configured to execute a digital servo algorithm to process the versions of the digitized signals to calculate a focus error signal (FES) from the versions of the digitized signals and to indicate a focus open condition based on the FES and the versions of the digitized signals.

Abstract: Methods and systems are described for correcting repeatable runout. In one aspect, an open loop tracking signal is received and squared. A discrete Fourier transform (DFT) of the squared open loop tracking signal is obtained. A velocity magnitude and an absolute value of the phase of the open loop tracking signal is determined. A RRO correction signal is iteratively constructed by performing a partial correction based on an initial phase selected and an initial velocity amplitude, measuring a relative velocity amplitude, performing a partial control correction using the initial phase and relative velocity amplitude if the amplitude is smaller than an initial amplitude or using the initial phase rotated by one hundred eighty degrees and the relative velocity amplitude if the amplitude is larger than an initial amplitude, and repeating the above steps until a tracking controller can perform closed loop control of the track to optical pickup unit velocity.