Abstract: A signal quality detection circuit has a sampling circuit and a comparing circuit. The sampling circuit samples an input signal associated with a target device according to a plurality of nominal sampling points, and generates a plurality of sampled bits corresponding to the nominal sampling points, respectively. The nominal sampling points are set by different combinations of sampling time and sampling reference voltage, and the number of the nominal sampling points is larger than four. The comparing circuit generates a signal quality detection result by performing comparison according to the sampled bits.

Abstract: In an optical disc apparatus for reproducing information recorded on a track of an optical disc, an optical head irradiates a light beam onto the track, detects a reflected light reflected by the track, and generates a reproduction signal based on the reflected light. A decoder circuit decodes the reproduction signal, and generates a decoded signal including information recorded on the track. A correlation detector circuit calculates a cross-correlation value between the reproduction signal and the decoded signal. A servo circuit detects a deviation amount of an irradiation position of the light beam onto the track, from the reproduction signal, and controls the irradiation position of the optical head based on the cross-correlation value and the deviation amount.

Abstract: A circuit for enabling an adaptation of an automatic gain control circuit comprises an automatic gain control (ACG) circuit configured to receive an input signal and to generate a boosted input signal. An average peak signal magnitude adaptation circuit is configured to receive an output of a decision circuit and to generate an average peak signal magnitude. An average peak signal target calculation circuit is configured to receive the average peak signal magnitude and detected peak signal magnitudes, wherein the average peak signal magnitude adaptation circuit generates a target peak signal magnitude. An AGC adaptation circuit is configured to receive an average peak signal magnitude and the target peak signal magnitude, wherein the AGC adaptation circuit provides an AGC control signal to the AGC circuit to maximize the effective signal magnitude within an acceptable linearity range.

Abstract: A differential phase detector for an optical storage system is set forth. The differential phase detector includes a photodetector circuit arranged to detect light deviations associated with radial errors in the optical storage system. A non-linear equalizer is in communication with the photodetector circuit. The output of the non-linear equalizer is in communication with signal processing circuitry. The signal processing circuitry uses the equalized signals to generate one or more radial error signals.

Abstract: Aspects of the disclosure provide a method for calibrating gains of an optical storage servo system having a plant. The method includes translating a first signal of the plant from a time domain effort signal into a frequency domain effort signal, translating a second signal of the plant from a time domain error signal into a frequency domain error signal, determining a first gain of the optical storage servo system based on the first signal and the second signal, comparing a third signal from an optical disk of the optical storage servo system with a predetermined threshold, and asserting a defect flag when the third signal drops below the predetermined threshold to avoid calibrating the first gain based on the first signal and the second signal.

Abstract: Various embodiments of the present invention provide circuits, systems and methods for data processing. For example, a data processing system is disclosed that includes: a data detector circuit, a filter circuit, a gain error generation circuit, and a multiplier circuit. The data detector circuit is operable to apply a data detection algorithm to a data set to yield a detected output. The filter circuit is operable to filter the detected output to yield a filtered output. The gain error generation circuit is operable to calculate an error value based upon a combination of an instance of the data set and a corresponding instance of the filtered output. The multiplier circuit operable to multiply the instance of the data set by a gain feedback value to yield a gain corrected output. The gain feedback value is derived from the error value.

Abstract: Provided are a light detecting element, and an optical pick-up device and an optical disc drive including the light detecting element. The light detecting element includes a terminal resistance unit that is provided between an amplification unit and an output port to limit an electric current of the output signal.

Abstract: Asymmetry and offset compensation for a data signal may be performed by a compensation circuit as disclosed. A circuit can be configured to generate a compensated data signal from a data signal, and can include: an input node inputting the data signal, an offset coefficient feedback loop configured to calculate an offset coefficient based on the data signal, a scaling unit configured to scale the offset coefficient by a first predetermined value (the scaled offset coefficient representing an estimate of an asymmetry coefficient), an asymmetry coefficient feedback loop configured to calculate the asymmetry coefficient based on the data signal and an initial value, a signal selection unit that causes the circuit to calculate the compensated data signal using the asymmetry coefficient, and an output node that outputs the compensated data signal.

Abstract: Aspects of the disclosure provide a method for calibrating gains of an optical storage servo system having a plant. The method includes translating a first signal of the plant from a time domain effort signal into a frequency domain effort signal, translating a second signal of the plant from a time domain error signal into a frequency domain error signal, determining a first gain of the optical storage servo system based on the first signal and the second signal, comparing a third signal from an optical disk of the optical storage servo system with a predetermined threshold, and asserting a defect flag when the third signal drops below the predetermined threshold to avoid calibrating the first gain based on the first signal and the second signal.

Abstract: An optical information recording medium reproducing apparatus 1 includes: a signal detecting/extracting section 15 extracting, from reproduction signal data, extracted reproduction signal data corresponding to a predetermined data pattern; a calculating circuit 10 calculating, from the extracted reproduction signal data, a reproducing power control value for controlling laser light reproducing power; and a reproducing power control section 16 controlling the reproducing power based on the reproducing power control value. The predetermined data pattern is obtained from a space which is sandwiched between marks of ?/2NA or longer and is shorter than ?/4NA and/or a mark which is sandwiched between spaces of ?/2NA or longer and is shorter than ?/4NA.

Abstract: High power optical disc drives are disclosed. The drives are configured to deliver laser energy having a power of at least about 25 mW as measured at DVD 1× write speed upon first contact with the surface of an optical disc.

Abstract: In one embodiment the present invention includes a qualification circuit that controls a read channel in a data storage device. The qualification circuit includes a first circuit and a second circuit. The first circuit receives a first signal and generates a second signal based on a signal quality of the first signal. The second circuit receives the second signal, an envelope-derived error signal resulting from performing envelope derived error detection, and a decision-aided error signal resulting from performing decision aided error detection. The second circuit modifies the envelope-derived error signal and the decision aided error signal according to the second signal. The second circuit generates a control signal that controls the read channel according to the envelope-derived error signal and the decision-aided error signal having been modified.

Abstract: A high sensitivity GPS receiver includes an acquisition engine and a tracking engine. The acquisition engine processes GPS satellite data at data rate that is substantially equal to twice the coarse acquisition (CA) code chip rate. This data rate advantageously enables the acquisition engine to process GPS satellite data with relatively less hardware area than traditional GPS acquisition approaches. In one embodiment, the high efficiency acquisition engine may be over-clocked, thereby allowing different phases of a CA code to be correlated quickly. The tracking engine can advantageously processes GPS satellite data at a data rate that does not have an integer relationship to the CA code chip rate.

Abstract: It is an object of the present invention to provide an optical recording medium containing a laminated structure of a first deformable material layer containing a phase-change material that absorbs light at a recording wavelength to generate heat and is subject to exothermic melting and deformation and a second deformable material layer containing a material which contains a silicon oxide (SiOx; 0<x?2) that transmits light and is subject to thermal deformation and alteration. After information is recorded, the thickness of the first deformable material layer is changed according to the recorded information making center of the recorded marks thicker than the ends and the second deformable material layer is deformed and altered corresponding to the concave-convex-pattern formed on the first deformable material layer based on the recorded information and when the information is reproduced, the first deformable material layer is altered from solid to molten state.

Abstract: A phase detector comprises a first slicing circuit that generates a first digital signal corresponding to a logic state of a first generally continuous signal. A second slicing circuit generates a second digital signal corresponding to a logical state of a second generally continuous signal. Phase detector logic compares triggering edges of the first and second digital signals to generate a phase difference signal having a pulse width corresponding to a phase difference between the first and second generally continuous signals. Aberration compensation circuitry is in communication with the phase detector logic to ensure generation of the phase difference signal in the presence of signal aberrations occurring at the triggering edges of the first and second digital signals.

Abstract: A comparator includes a variable-gain amplifier circuit configured to vary an amplitude of an input signal by changing a gain in accordance with a control signal, and a comparison section configured to compare a slice level interlocked with a signal level received from the variable-gain amplifier circuit with an output signal received from the variable-gain amplifier circuit and generate an output signal in accordance with a comparison result.

Abstract: A signal processing device for optical disks includes a reflected light process section configured to convert reflected light received by an optical pickup into an electric signal based on a first gain, wherein the optical pickup emits laser light to an optical disk and receives reflected light from the optical disk; a servo signal generation section configured to generate a servo signal by using the electric signal generated by the reflected light process section; a servo signal control section configured to control the servo signal so that a change in the amplitude of the servo signal, in response to an increase or decrease of the amount of the reflected light from the optical disk, is suppressed using an attenuator that attenuates the servo signal generated by the servo signal generation section by a factor of a second gain; and a gain setting section configured to set the first gain to the reflected light process section and the second gain to the servo signal control section substantially simultaneously.

Abstract: A gain calibration method for optical storage servo systems in which, plant gain calibration is used by injecting a reference sine wave r into an optical storage servo system, obtaining an effort signal m at the input of the servo plant and an error signal y at the output of the servo plant, using a DFT (Discrete Fourier Transformation) to translate the time domain signals m and y into frequency responses M and Y, calculating a Y-to-M ratio, and using the magnitude of the Y-to-M ratio as the plant gain K of the servo system. The servo system's sensor gain K1 at the outermost layer of a disk may be calibrated by, e.g., the conventional peak-to-peak measurement. Since K=K1·K2, the servo system's actuator gain K2 at the outermost layer of the disk may be obtained. Because the actuator gain K2 is the same for all layers of a disk, the variation of the sensor gain K1 at an inner layer may follow that of the plant gain K at that layer.

Abstract: Before initiation of tracking control, an optical disk device performs an offset amount obtaining operation, in which a difference between a middle value of the amplitude of a tracking error signal and a predetermined reference value is obtained as an offset amount. After the initiation of the tracking control, the optical disk device initiates an attenuation operation, in which an offset amount attenuation section attenuates the offset amount obtained by the offset amount obtaining operation to obtain an attenuated offset amount, while initiating, with an initial value being 0, an estimation operation, in which an observer estimates the offset amount according to a tracking driving signal to obtain an estimated offset amount. The optical disk device corrects the tracking error signal by using the attenuated offset amount obtained by the attenuation operation and the estimated offset amount obtained by the estimation operation.

Abstract: A normal resolution component included in a readout signal of a super resolution optical disc is canceled to improve quality of the readout signal. The normal resolution component is separated from the readout signal of the super resolution optical disc by using a normal resolution selection filter such as a low pass filter, a mark length determination circuit, and then the normal resolution component is subtracted from an original readout signal while gain and a phase are appropriately controlled. Thereby, an influence of crosstalk due to the normal resolution component is reduced.

Abstract: An optical disk drive, and a method of determining a write strategy thereof. In the method of determining a write strategy of an optical disk drive where a mark and a space are formed on an optical disk by a laser beam to display write information and information is written or reproduced, write quality is evaluated by combining at least two of power- and pulse-based parameters defining a writing multi pulse, and the at least two parameters are changed on a 2-dimensional matrix. The power- and pulse-based parameters indicating specific write quality are determined as strategy parameters, based on evaluated results of the write quality.

Abstract: High power optical disc drives are disclosed. The drives are configured to deliver laser energy having a power of at least about 25 mW as measured at DVD 1X write speed upon first contact with the surface of an optical disc.

Abstract: An asymmetry compensator for a partial response maximum likelihood (PRML) decoder, which is utilized to remove and eliminate the asymmetric component of the regenerating signal read from the optical recording medium, thereby effectively solving the problem of the asymmetry of the optical disk regenerating signal. The compensator includes an offset controller and a gain controller. The offset controller determines the central level of the regenerating signal thus to adjust the offset of the regenerating signal while the gain controller is arranged to adjust the gain of the regenerating signal.

Abstract: The present invention relates to a method of performing a writing power calibration for optical recording on an optical storage medium having a spiral track structure, comprising the steps of: selecting a first partition (10) on the track structure having a first track (12) and an adjacent second track (14) that do both not contain written information on track portions (16, 18) within the first partition (10), wherein the second track (14) may be neighboured by a third track (20) that may have a track portion (22) within the first partition (10) containing written information, writing to the track portion (16) of the first track (12) within the first partition (10) using a predetermined writing power profile of a laser beam, reading information written to the first track (12) within the first partition (10), and determining a relation between an asymmetry value and laser power on the basis of the writing power profile and the information read from the first track (12).

Abstract: An optical information recording medium reproducing apparatus 1 includes: a signal detecting/extracting section 15 extracting, from reproduction signal data, extracted reproduction signal data corresponding to a predetermined data pattern; a calculating circuit 10 calculating, from the extracted reproduction signal data, a reproducing power control value for controlling laser light reproducing power; and a reproducing power control section 16 controlling the reproducing power based on the reproducing power control value. The predetermined data pattern is obtained from a space which is sandwiched between marks of ?/2NA or longer and is shorter than ?/4NA and/or a mark which is sandwiched between spaces of ?/2NA or longer and is shorter than ?/4NA.

Abstract: An apparatus for detecting the wobble carrier frequency of an optical disk is disclosed. The apparatus comprises an offset canceller, a binary conversion module, an adjustable band pass filter, and a frequency detection module. The offset canceller cancels the direct current offset of a first wobble signal to obtain a second wobble signal. The binary conversion module converts the second wobble signal to a binary data stream. The adjustable band pass filter passes only an adjustable frequency range of the binary data stream to generate a filtered signal, wherein the center frequency of the adjustable frequency range is sequentially adjusted. The frequency detection module then determines maximum amplitude of the filtered signal, and determines the center frequency of the adjustable frequency range according to which the filtered signal with the maximum amplitude is generated, wherein the wobble carrier frequency is the center frequency corresponding to the maximum amplitude.

Abstract: The invention provides a wobble detection circuit. An exemplary embodiment of the wobble detection circuit comprises an automatic gain control module, an analog to digital converter, a digital band pass filter, and a digital band pass filter. The automatic gain control module amplifies a first input signal and a second input signal detected by a pickup head to the same magnitude to obtain a first amplified signal and a second amplified signal. The adder then subtracts the second amplified signal from the first amplified signal to obtain an analog wobble signal. The analog to digital converter then converts the analog wobble signal to a first digital wobble signal. Finally, the digital band pass filter accepts frequency components of the first digital wobble signal within a pass band and rejects frequency components of the first digital wobble signal outside the pass band to obtain a second digital wobble signal.

Abstract: The invention provides an apparatus for demodulating an Address In Pre-groove (ADIP) symbol. The ADIP symbol is carried by a wobble signal of an optical disk and comprises a series of ADIP bits permuted according to one of a plurality of permutation patterns to make up the ADIP symbol. A wobble extraction module extracts the wobble signal from the optical disk. A reference wobble generator generates a reference wobble with the same frequency and phase as a fundamental frequency and phase of a positive wobble cycle of the wobble signal. A waveform difference measurement module then measures a difference between the wobble signal and the reference wobble to obtain a series of difference measurement values respectively corresponding to the ADIP bits. A pattern matching module then compares probabilities of the permutation of the ADIP bits agreeing with each of the permutation patterns according to the difference measurement values to determine the ADIP symbol.

Abstract: An optical storage device and a blank detection method thereof are disclosed. An RF signal is obtained from an optical disc. A various gain amplifier amplifies the RF signal based on a control signal. An analog to digital converter samples the amplified RF signal to obtain a data signal. An auto gain controller updates the control signal based on amplitude of the data signal. A blank detector detects blankness of the data signal based on a threshold. The threshold is provided by a threshold generator based on the control signal. If the amplitude of the data signal does not exceed the threshold, the blank detector sends a hold signal to suspend update of the control signal.

Abstract: It is an object of the present invention to provide an optical recording medium containing a laminated structure of a first deformable material layer containing a phase-change material that absorbs light at a recording wavelength to generate heat and is subject to exothermic melting and deformation and a second deformable material layer containing a material which contains a silicon oxide (SiOx; 0<x?2) that transmits light and is subject to thermal deformation and alteration. After information is recorded, the thickness of the first deformable material layer is changed according to the recorded information making center of the recorded marks thicker than the ends and the second deformable material layer is deformed and altered corresponding to the concave-convex-pattern formed on the first deformable material layer based on the recorded information and when the information is reproduced, the first deformable material layer is altered from solid to molten state.

Abstract: The present invention relates to an optical holographic device and a corresponding method for reading out a data page recorded in a holographic recording medium (106). In order to improve the bit error rate a reconstruction means (115) provided for reconstructing a dark and a light image from a separate checkerboard page comprising a pattern of dark and light pixels or from the detected imaged data page, and an image correction means (116) is provided for correcting said detected imaged data page by gain compensation using said reconstructed dark and light images.

Abstract: A signal processing apparatus is provided with a converter for converting at least one analog light detection signal into a digital light detection signal, and a signal generator for generating at least one servo error signal by subjecting the digital light detection signal to a predetermined operation process. The signal generator has a function of modifying contents of the operation process.

Abstract: A method for determining a sub-beam add signal (SBAD) value is provided. At first, a jth read SBAD value is obtained at the jth read status. Next, the jth write SBAD value is determined according to the (j?1)th write SBAD gain at the jth write status. Then, the jth SBAD multiple is obtained according to the jth write SBAD value and the jth read SBAD value. Next, the (j?1)th write SBAD gain is changed into the jth write SBAD gain according to the jth SBAD multiple. At last, the level of the (j+1)th write SBAD value is adjusted according to the jth write SBAD gain at the (j+1)th write status.

Abstract: A gain control system for compact disc laser reader is provided, comprising two AGCs, comparator and a calibration unit. The first AGC receives a calibration signal to generate a first output signal with a first gain. The second AGC receives the calibration signal to generate a second output signal with a second gain. The comparator is coupled to the first and second AGCs, comparing the first output signal and the second output signal to generate a differential signal. The calibration unit, coupled to the comparator, adjusts the first control voltage or the second control voltage based on the differential signal, such that the amplitudes of the first output signal and the second output signal are compensated identically.

Abstract: A data slice signal generation method of an optical disk drive, which uses a disk including header areas and data areas of different materials, includes the following steps. First, a data slice signal is generated according to the RF signal read by the optical pickup head of the optical disk drive, and the data slice values, reflecting the central levels of the RF signal, of the data slice signal at the beginnings of the header area and data area are preset. Secondly, when the optical pickup head of the optical disk drive enters a header area or a data area, the data slice signal takes the preset data slice value of the header area or data area, respectively. Then, the data slice signal is adjusted to approach the central levels of the waves of the RF signal by one wave after another.

Abstract: An optical disk system includes at least one photo detector connected with a variable gain amplifier, a slicer, and a generator which is in the feedback path between the slicer and amplifier. A differential time delay detector provides the output of the optical disk system. The generator is configured for controlling the amplifier non-linearly so that time constants of the control loop of the amplifier which depend upon the level of the input signals are compensated and the timing behavior of the control loop of the amplifier has a more continuous character. A capacitor forms part of an integrator for making the mean value of the output voltage signal of the slicer equal to zero.

Abstract: An apparatus for detecting the wobble carrier frequency of an optical disk is disclosed. The apparatus comprises an offset canceller, a binary conversion module, an adjustable band pass filter, and a frequency detection module. The offset canceller cancels the direct current offset of a first wobble signal to obtain a second wobble signal. The binary conversion module converts the second wobble signal to a binary data stream. The adjustable band pass filter passes only an adjustable frequency range of the binary data stream to generate a filtered signal, wherein the center frequency of the adjustable frequency range is sequentially adjusted. The frequency detection module then determines maximum amplitude of the filtered signal, and determines the center frequency of the adjustable frequency range according to which the filtered signal with the maximum amplitude is generated, wherein the wobble carrier frequency is the center frequency corresponding to the maximum amplitude.

Abstract: The invention provides an automatic gain controller processing an input signal for wobble detection circuit. An exemplary embodiment of the automatic gain controller comprises an envelope detection module, an analog to digital converter, a digital control module, a digital to analog converter, and a variable gain amplifier. The envelope detection module detects an envelope magnitude of an amplified signal. The analog to digital converter converts the envelope magnitude from analog to digital to obtain a digital envelope signal. The digital control module determines a digital gain signal for amplification of the input signal according to the digital envelope signal. The digital to analog converter converts the digital gain signal to an analog gain signal. The variable gain amplifier then amplifies the input signal according to the analog gain signal to obtain the amplified wobble signal.

Abstract: The invention provides an apparatus for demodulating an Address In Pre-groove (ADIP) symbol. The ADIP symbol is carried by a wobble signal of an optical disk and comprises a series of ADIP bits permuted according to one of a plurality of permutation patterns to make up the ADIP symbol. A wobble extraction module extracts the wobble signal from the optical disk. A reference wobble generator generates a reference wobble with the same frequency and phase as a fundamental frequency and phase of a positive wobble cycle of the wobble signal. A waveform difference measurement module then measures a difference between the wobble signal and the reference wobble to obtain a series of difference measurement values respectively corresponding to the ADIP bits. A pattern matching module then compares probabilities of the permutation of the ADIP bits agreeing with each of the permutation patterns according to the difference measurement values to determine the ADIP symbol.

Abstract: An asymmetry measurement apparatus is disclosed. The asymmetry measurement apparatus is designed for detecting the recorded data reproduction waveform of an optical storage device in digital domain. The asymmetry measurement apparatus includes an Analog to Digital Converter (ADC) for converting an analog signal to a digital signal; a detection unit for detecting plurality values of the digital signal; and an asymmetry calculation unit for generating an asymmetry value of the digital signal according to the plurality values.

Abstract: An optical storage device and a blank detection method thereof are disclosed. An RF signal is obtained from an optical disc. A various gain amplifier amplifies the RF signal based on a control signal. An analog to digital converter samples the amplified RF signal to obtain a data signal. An auto gain controller updates the control signal based on amplitude of the data signal. A blank detector detects blankness of the data signal based on a threshold. The threshold is provided by a threshold generator based on the control signal. If the amplitude of the data signal does not exceed the threshold, the blank detector sends a hold signal to suspend update of the control signal.

Abstract: An objective of the present invention is to enhance reliability of recorded data by preventing deterioration of OPC (Optimum Power Calibration) accuracy due to an influence of inter-layer interference in an optical disk device capable of writing in a multilayer optical disk. Aiming at the objective, a relationship between asymmetry and a signal modulation depth, which are measured by use of a standard driver is referred, and thereby an offset caused by a device, a disk, a writing state of another layer and the like is compensated. Thus, OPC is executed.

Abstract: The invention provides a wobble detection circuit. An exemplary embodiment of the wobble detection circuit comprises an automatic gain control module, an analog to digital converter, a digital band pass filter, and a digital band pass filter. The automatic gain control module amplifies a first input signal and a second input signal detected by a pickup head to the same magnitude to obtain a first amplified signal and a second amplified signal. The adder then subtracts the second amplified signal from the first amplified signal to obtain an analog wobble signal. The analog to digital converter then converts the analog wobble signal to a first digital wobble signal. Finally, the digital band pass filter accepts frequency components of the first digital wobble signal within a pass band and rejects frequency components of the first digital wobble signal outside the pass band to obtain a second digital wobble signal.

Abstract: The present invention has an object to stably reproduce wobble signals of all disks of CD-R/RW, DVD-R/RW and DVD-RAM by one wobble signal reproducing circuit. In the wobble signal reproducing circuit, an AGC (AUTOMATIC GAIN CONTROL) circuit for equating a push-pull circuit output of a wide range and an RF amplitude of an optical detector output of two systems obtained by push-pull, and an AGC (AUTOMATIC GAIN CONTROL) circuit for making a wobble amplitude uniform are provided with a function to hold a gain or to change over a response time constant, and at the time of reproduction of the DVD-R/RW, a land pre-pit region is detected by the push-pull output to hold AGC (AUTOMATIC GAIN CONTROL) or change over a response time constant. Besides, in an address information recording region (PID region) at the time of reproduction of the DVD-RAM, the AGC (AUTOMATIC GAIN CONTROL) is held or the response time constant is changed over.

Abstract: A feedback loop structure including an operational amplifier unit (1) for amplifying a reproduction signal of recorded information and a gain/offset control unit (6) for controlling an amplitude and an offset of an output of the operational amplifier unit (1) so that each of the amplitude and the offset becomes a predetermined value is adopted, and accurate information for an asymmetry amount is obtained by a binarization unit (7) for receiving the output of the operational amplifier unit (1) and performing binarization while adjusting a slice level by feedback control so that a duty ratio after the binarization substantially becomes a predetermined value. Based on the asymmetry amount information, a judgment level of a Viterbi decoding unit (15) is changed, thereby reducing a reproduction error rate.

Abstract: A method and apparatus to dynamically adjust the amplitude of a signal comprising information read from an information storage medium. The method first forms (N) digital signals comprising information read from an information storage medium. The method provides a first signal comprising information read an information storage medium, wherein that first signal is one of the (N) digital signals. The method provides a first gain level, and calculates a first gain adjusted signal comprising the multiplication product of the first signal and the first gain level. To dynamically adjust that gain level, Applicants' method determines a gain error. Using that gain error, Applicants' method then calculates a second gain level by multiplying the gain error times a multiplier coefficient, and adding that multiplication product to the first gain level.

Abstract: An apparatus for detecting a pre-pit signal at different laser power intensities of an optical disk drive. The apparatus includes an amplifier for receiving a push-pull signal acquired from an optical disk to generate an adjusted signal, a multiplexer for receiving the push-pull signal and the adjusted signal and selecting the push-pull signal or the adjusted signal as a slicing signal for output according to a power state signal, and a slicer for receiving the slicing signal and slicing the slicing signal according to a slicing level to generate the pre-pit signal. Thus, the apparatus only needs one set of slicer to correctly slice the pre-pit signal.

Abstract: The signal processor includes an analog filter, an analog-to-digital (A-D) converter, an adaptive equalization filter, a quality value calculating circuit, and a control circuit. The analog filter removes high-frequency noises of a played-back signal from a recording medium and amplifies a specific frequency band of the played-back signal. The A-D converter converts the played-back signal from the analog filter into a digital signal. The adaptive equalization filter performs waveform equalization of the played-back signal from the A-D converter while adjusting a tap coefficient of the adaptive equalization filter so as to reduce a difference between an output of the adaptive equalization filter and a target value. The quality value calculating circuit calculates a quality value based on the difference between the output of the adaptive equalization filter and the target value.

Abstract: A disk drive servo system for eccentricity compensation and a method thereof includes an error detector detecting a position error between an actual position and a predetermined nominal reference position of a turntable actuator, a feedback unit generating and outputting a first control value to compensate for the position error received from the error detector, a learning controller calculating, storing, and outputting a second control value to compensate for eccentricity at one or more predetermined speeds of the disk drive, and a gain/phase adjustor providing gain and phase compensation information corresponding to the second control value of the learning controller according to frequency response characteristics of the turntable actuator at the one or more predetermined speeds.

Abstract: An optical disk apparatus capable of determining the type of a loaded optical disk. In accordance with an RF signal output from a pickup, an RF processing section of the optical disk apparatus generates a focus signal (an FOK signal), which is an envelope of the RF signal, and supplies the focus signal to a DSP. In the DSP, the level of the FOK signal is compared with a threshold value, and a result of comparison is supplied to a controller. The controller determines occurrence of defocus on the basis of the comparison result. Concurrently, the controller quantitatively evaluates the level of the FOK signal by means of sequentially changing the threshold value, thereby determining the type of the optical disk on the basis of the reflectivity of the optical disk.