Abstract: Metadata computation apparatus includes a host interface, a storage interface and one or more processors. The host interface is configured to communicate over a computer network with one or more remote hosts. The storage interface is configured to communicate with one or more non-volatile memories of one or more storage devices. The processors are configured to manage local storage or retrieval of media objects in the non-volatile memories, to compute metadata for a plurality of media objects that are stored, or are en-route for storage, on the storage devices, wherein the media objects are of multiple media types, wherein the computed metadata tags a target feature in the media objects of at least two different media types among the multiple media types, and to store, in the non-volatile memories, the metadata tagging the target feature found in the at least two different media types, for use by the hosts.

Abstract: According to one embodiment, a communication device includes a control circuit. The control circuit determines an output waveform of the data to be received from an external device. The control circuit stores information relating to the output waveform into a nonvolatile memory in response to determining of the output waveform of the data from among N (N is a natural number of three or more) types of output waveforms. The control circuit determines an output waveform of the data from among M or less types of output waveforms in the N types of output waveforms (M<N) (M is a natural number of N?2 or more) based on the information stored in the nonvolatile memory, when the information is stored in the nonvolatile memory.

Abstract: A receiver includes a variable resolution analog-to-digital converter (ADC) and variable resolution processing logic/circuitry. The processing logic may use feed-forward equalization (FFE) techniques to process the outputs from the ADC. When receiving data from a channel having low attenuation, distortion, and/or noise, the ADC and processing logic may be configured to sample and process the received signal using fewer bits, and therefore less logic, than when configured to receiving data from a channel having a higher attenuation, distortion, and/or noise. Thus, the number of (valid) bits output by the ADC, and subsequently processed (e.g., for FFE equalization) can be reduced when a receiver of this type is coupled to a low loss channel. These reductions can reduce power consumption when compared to operating the receiver using the full (i.e., maximum) number of bits the ADC and processing logic is capable of processing.

Abstract: A method and apparatus for adapting, in parallel, two operating parameters associated with an equalizer circuit is disclosed. A control circuit may be configured to initialize a first operating parameter to an initial value, and modify a second operating parameter based upon the initial value of the first parameter. In response to determining a peak amplitude of an output signal of the equalizer circuit is less than a threshold value, the control circuit may be further configured to select a new value for the first operating parameter and adapt, in response to the change in the first operating parameter, the second operating parameter based on a performance metric of the equalizer circuit.

Abstract: This invention relates to a system, method and computer program product for determining which anytime technique is the most efficient at solving an anytime problem using a first anytime technique and a second anytime technique to determine a first and a second plurality of solutions, respectively, wherein each of the first and the second the plurality of solutions includes a value and an associated computation time, respectively, and each of the first and the second plurality solutions including a minimized value and associated computation time, respectively. Determining a set of delta value ordinates and computation time ordinates. Determining a representative value ordinate and representative computation time ordinate. Determining an efficient anytime technique.

Abstract: A header region evaluation circuit includes a difference signal detection unit that detects a difference signal proportional to a difference in amounts of received light from an optical disc, a high pass filter that switches a plurality of cutoff frequencies according to a passband control signal, removes a low frequency component from the difference signal, and generates a difference signal HPF output, a waveform shaping unit that generates a shaping signal to convert the difference signal HPF output into a pulse, and a physical header detection sequencer that generates a groove detection signal for evaluating whether the physical header region is either one of a groove and an inter-groove and generates a passband control signal for controlling the cutoff frequency to be reduced for a difference signal corresponding to at least a part of the physical header region.

Abstract: A frequency detection apparatus and method for generating a stable clock signal synchronized with an input signal and a signal boost filter used in the frequency detection apparatus and method, the frequency detection apparatus includes a signal boost filter filtering out the high frequency component of an input signal and boosting the high frequency component, and a frequency detector receiving an input signal with the boosted high frequency component and a clock signal, detecting a frequency difference between the input signal and the clock signal, and producing a control voltage corresponding to the frequency difference. Accordingly, even when there is a big difference between the frequency of the input signal and an oscillating frequency, a frequency error can be stably detected. Thus, a stable clock signal can be obtained.

Abstract: A method for automatically tuning an analog filter includes the steps of making an analog filter filter an input signal to output a filtered signal according to a filtering characteristic, sampling the filtered signal to generate sampled data, computing a sector data number of the sampled data that does not complying with a specified data format, and tuning the filtering characteristic of the analog filter according to the sector data number.

Abstract: An optical disc device including a high frequency band processing circuit for removing low frequency components of signals outputted from plural photodetectors of a pickup, and generating various kinds of signals required for recording/playback of an optical disc by digital processing after performing AD conversion by a high-speed low-bit AD converter; and a low frequency band processing circuit for removing high frequency components of the signals outputted from the respective photodetectors of the pickup, and generating various kinds of signals required for recording/playback of an optical disc by digital processing after performing AD conversion by a low-speed high-bit time-division AD converter.

Abstract: A waveform equalizer includes: a calculation circuit (7a) that permits free setting of the boost factor by which the gain, in a predetermined frequency range, for the input signal by varying the boost factor; and an all-pass filter (7b) that is connected to the stage preceding or following the calculation circuit, that has a first conductance amplifier and a second conductance amplifier, and that adjusts and thereby corrects the group delay characteristic of the input signal by varying the conductance of at least one of the first and second conductance amplifiers.

Abstract: A signal processing circuit for adjusting an input signal and generating a corresponding digital output signal in an optical disk driver is provided. The signal processing circuit includes an attenuator for receiving and attenuating the input signal and then generating an attenuated output signal; a gain controllable amplifier for receiving and amplifying the input signal and then generating an amplified output signal; a control unit providing a control signal and a select signal, the control signal is directed to the attenuator and the gain controllable amplifier for enabling/disabling the attenuator and the gain controllable amplifier and for controlling their gains such that one of the attenuator and gain controllable amplifier is enabled at a time; and a waveform adjuster circuit for adjusting the amplified/attenuated output signal delivered from the gain controllable amplifier or the attenuator so as to generate the digital signal related to the input signal.

Abstract: An information playback apparatus comprises an input amplifier to which an RF signal reproduced from an optical disc is input; a high-pass filter to which the output of the input amplifier is input; an AD converter to which the output of the high-pass filter is input; a lag lead filter to which the output of the AD converter is input; and a demodulator for digitally processing the output of the lag lead filter to demodulate it as a binary signal. Thereby, an optical disc playback apparatus that realizes a DVD-RAM playback function at low cost can be realized.

Abstract: An equalizer for a high density optical disc reproducing apparatus and an equalizing method therefore are provided. The equalizer includes: a non-linear transformer, which transforms an input signal according to predetermined threshold levels; a cosine transform filter, which inverts phases of high frequency spectrum components of an output signal of the non-linear transformer; a high boost filter, which increases amplitudes of high frequency spectrum components of the input signal; and an adder, which adds an output signal of the cosine transform filter with an output signal of the high boost filter. Therefore, the equalizer can increase recording density of the optical disc in the high density optical disc reproducing apparatus and accordingly increase recording amount of information, by reducing inter-signal interference (ISI) and increasing a signal-to-noise ratio in the output signal of the equalizer. Also, the equalizer has a simple configuration.

Abstract: A PLL circuit having an analog-to-digital converter; a phase error detecting circuit; and an oscillator, in which the phase error detecting circuit includes: phase error detecting means detecting a phase error from a data stream signal and a data stream signal 1 clock cycle earlier; absolute value comparing means detecting an absolute value of the phase error detected exceeding a predetermined threshold; holding means holding a polarity of the phase error, as of a timing of the detection by the absolute value comparing means, for a period of the detection; anticoincidence detecting means detecting anticoincidence between the polarity held by the holding means and a polarity of the phase error detected by the phase error detecting means; and polarity inverting means that provides the phase error detection signal by inverting the polarity of the phase error in detection of anticoincidence, or without inverting the polarity in detection of no anticoincidence.

Abstract: Without waiting for the rotational speed of an optical disk reaches a rotational speed (Vb) for a reproduction process, a cutoff frequency (Fca) of an RF signal and a boost amount (Bt) for an equalizer circuit are detected, and, with using the rotational speed (Va) of the optical disk at this detection, the cutoff frequency (Fc) by which jitter of the RF signal is optimized when the optical disk is rotated at the rotational speed (Vb) for the reproduction process is calculated by the equation of Fc=Fca+k(Vb?Va), and then set. Therefore, the time between the timing when the user conducts an input operation for starting reproduction, and that when reproduction is actually started can be shortened, and the usability can be improved.

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 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: In a data reproduction method and apparatus of the present invention, a Viterbi detection unit is provided, the Viterbi detection unit having a plurality of detectors each providing a first partial response signal with a first constraint length from a first sequence of samples derived from a first readout signal. One of connection and disconnection of the plurality of detectors in the Viterbi detection unit is selected in response to a timing signal, wherein, when the connection of the plurality of detectors is selected, the Viterbi detection unit provides a second partial response signal with a second constraint length from a second sequence of samples derived from a second readout signal, the second constraint length being different from the first constraint length.

Abstract: A method of reproducing information by scanning information marks, disposed with a predetermined mark pitch therebetween and recorded on tracks inside a predetermined information recording region, by an optical spot. The method includes detecting the size of the optical change resulting from the information mark, calculating a plurality of equalization coefficients used for an equalization processing for the size of the optical change detected for each of the information marks, and reducing the inter-symbol interference on the basis of the equalization coefficients by the equalization processing. The equalization coefficient used for the equalization processing of the size of the optical change by a first information mark is greater than said equalization coefficient used for the equalization processing of the size of said optical change by a second information mark which is longer than the first information mark.

Abstract: A calibration of a loop gain in a digital servo system is presented. The loop gain can be calibrated measuring the response in a control signal generated by the digital servo system when the control signal is replaced by a sum of the control signal and a sinusoidal disturbance. The loop gain can be set to provide a desired gain, for example unity, between the control signal and the sinusoidal disturbance at a cross-over frequency.

Abstract: To correct a bit shift of binary data read from a medium and further enable correction of a bit error caused by mis-correction of the bit shift, a data recovery apparatus according to the present invention comprises: circuits for respectively correcting time at an intersection of a read signal and a slice signal; and a circuit for generating gray bits representing a time cell including an intersection, the time of the intersection being uncorrected and a time cell adjacent to the time cell, positioned in the direction of the intersection being shifted for correction.

Abstract: The reproduction method includes steps of: performing an addition operation on a detection signal obtained by the first light-detecting element group and a detection signal obtained by the second light-detecting element group so as to generate a summation signal and outputting the summation signal to a signal processing section; performing a difference operation on a detection signal obtained by the first light-detecting element group and a detection signal obtained by the second light-detecting element group so as to generate a differential signal and outputting the differential signal to the signal processing section; digitalizing the summation signal so as to generate a binary signal, and generating a binary signal edge pulse; when an amplitude which is equal to or greater than a predetermined value of the differential signal is detected, outputting the binary signal edge pulse as a reproduction edge pulse from the signal processing section; and generating the reproduction data.

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 first multiplier 251 multiplies a reproduced RF signal rf(t) by a DC component of an APC monitoring output signal m(t), which component is an output signal from an LPF 252, and then supplies a signal resulting from the multiplication to an arithmetic unit 255. A second multiplier 254 multiplies the reproduced RF signal rf(t) by a laser noise component of the APC monitoring output signal m(t), which component is an output signal from an HPF 253, and then supplies a signal resulting from the multiplication to the arithmetic unit 255. The arithmetic unit 255 subtracts the signal from the multiplier 254 from the signal from the multiplier 251 to thereby remove both an additive noise component and a modulated noise component of laser noise.

Abstract: The present invention realizes stable and more proper data reproduction even when a reproduced signal varies locally due to a noise or includes a steady distortion. In a data reproduction control method and apparatus, and an optical disk unit that adjust sampled values, in sampling a signal reproduced from a recording medium recorded with data, the frequencies of the levels of quantized data are counted, a histogram of the frequencies of the levels is created based on the counting results, and more accurate reproduced data is obtained by means of a distribution of the frequencies of the levels in the histogram.

Abstract: The present invention realizes stable and more proper data reproduction even when a reproduced signal varies locally due to a noise or includes a steady distortion. In a data reproduction control method and apparatus, and an optical disk unit that adjust sampled values, in sampling a signal reproduced from a recording medium recorded with data, the frequencies of the levels of quantized data are counted, a histogram of the frequencies of the levels is created based on the counting results, and more accurate reproduced data is obtained by means of a distribution of the frequencies of the levels in the histogram.

Abstract: The present invention is an optical detection system to detect various areas of an optical storage medium. The optical detection system comprises a pickup head, a signal adder and an adding comparator. The pickup head have a light source for providing an incident light beam to the data area and the header, and generating the corresponding reflective light beam. The pickup head detects the reflective light beam to generate left-side detection signals and right-side detection signals. The signal adder adds the amplitudes of the left-side detection signal and the right-side detection signal to generate an adding signal. The adding comparator compares the adding signal with a predetermined adding reference signal to generate a compared adding signal. According to the compared adding signal, the optical detection system can determine that the reflective light beam detected by the pickup head comes from the data area or the header.

Abstract: A piece of media, apparatus and method are provided wherein the piece of media may store the audio data as well as equalizer settings that permit the audio data to be equalized. In one embodiment, the piece of media stores equalized audio data and the equalizer settings. In accordance with the invention, in one embodiment, the equalizer-effect piece of media permits the audio data on the piece of media to be equalized even when the audio data player does not include an equalizer. In another embodiment, the equalizer-effect piece of media includes raw audio data and equalizer settings and permits an external equalizer to play equalized audio data without needing to set the equalizer. In a preferred embodiment, the piece of media may be compact disk.

Abstract: The present invention realizes stable and more proper data reproduction even when a reproduced signal varies locally due to a noise or includes a steady distortion. In a data reproduction control method and apparatus, and an optical disk unit that adjust sampled values, in sampling a signal reproduced from a recording medium recorded with data, the frequencies of the levels of quantized data are counted, a histogram of the frequencies of the levels is created based on the counting results, and more accurate reproduced data is obtained by means of a distribution of the frequencies of the levels in the histogram.

Abstract: There are provided a spindle motor 12, an optical head 20, a high-pass filter 31, low-pass filters 32 and 33, an adder 38, and a PLL 39. The spindle motor 12 rotatively drives an optical disk 11. The optical head 20 irradiates a laser beam onto a target track and both tracks adjacent to the target track on the optical disk 11 and detects a return light from each track. The high-pass filter 31 filters a high-frequency component in a signal used for detecting a return light from a target track in the optical head 20. Each of the low-pass filters 32 and 33 filters a low-frequency component in a signal used for detecting a return light from each of the adjacent tracks. The adder 38 operates output signals from the high-pass filter 31, and the low-pass filters 32 and 33. Based on a signal from the adder 38, the PLL 39 generates a reference signal used as a time reference for generating recording signals. An operation by the adder 38 nullifies a cross modulation component.

Abstract: A tracking error balance adjustment circuit, and a current control circuit used for a variable gain RF amplifier automatically controlled to output a signal having a predetermined amplitude. The tracking error balance adjustment circuit comprises two separate gain adjusting circuits, each having variable attenuation circuit having first gm amplifier of variable gm type, a second gm amplifier of variable gm type connected to the variable attenuation circuit, and an output circuit connected to the second gm amplifier, comprising an operational amplifier circuit having feedback resistor, wherein the first and second gm amplifiers are differentially controlled commonly by a control current.

Abstract: An equalizer for producing an equalized signal from an input signal. The input signal has a DC component. The equalizer includes a programmable filter and equalizer. A detector for generating a threshold signal from a preprocessed signal. The preprocessed signal is generated from the equalized signal. A comparator for comparing the preprocessed signal to the threshold signal to produce an output signal. A tracking device for tracking the DC component from the output signal.

Abstract: The method of sampling wobble components of the present invention is capable of realizing a disk drive unit, which can write data at high speed, and reducing manufacturing cost of the disk drive unit. The wobble components are sampled from laser beams reflected from an optical disk so as to write data on the optical disk. The laser beams are low power laser beams for reading data and high power laser beams for writing data. The method is characterized in that the wobble components of the reflected low power laser beams and the reflected high power laser beams are continuously sampled.

Abstract: A disc reproducing apparatus is disclosed, that comprises an optical pickup for reading a signal from a disc, a level slice PLL circuit for reproducing data from the signal read by the optical pickup, a signal processing unit for reproducing data with the clock signal reproduced by the level slice PLL circuit, and a range changing circuit for changing a linear velocity range (namely, a capture range) of the level slice PLL circuit in a time period at least after an occurrence of a reproduction command until data is reproduced from the disc at a target linear velocity corresponding to the reproduction command. Thus, even in a transient state such as an accelerating/decelerating state of a CD-ROM or the like, data can be properly reproduced from the disc.

Abstract: A recorded signal reproducing method for an optical recording medium that is adapted to accurately reproduce a signal recorded on the optical recording medium having wobbled tracks. In the method, a signal included in the optical recording medium is picked up and a specified period of signal included the picked-up signal is detected. The picked-up signal is compensated in accordance with the specified period signal.

Abstract: An apparatus operates for recording and reproducing information on and from a recording medium formed with a track and pre-pits. The track has a wobble. The pre-pits are in a predetermined phase relation with the wobble of the track. The apparatus includes a pickup for reproducing a signal from the recording medium. A limiter operates for limiting an amplitude of the signal reproduced by the pickup in response to a limiting level, and thereby processing the signal reproduced by the pickup into a limiting-resultant signal. A filter operates for suppressing components of the limiting-resultant signal, and thereby processing the limiting-resultant signal into a filtering-resultant signal. The components have specified frequencies, and are caused by the pre-pits. The limiting level for the limiter is generated in response to the filtering-resultant signal. A signal caused by the wobble of the groove is extracted from the filtering-resultant signal.

Abstract: A prepit detection unit for detecting prepits in an optical recording and reproducing apparatus for recording and reproducing information on a recordable, optical record medium including preinformation such as address information in a prepit form. In the prepit detection unit, for first and second divisional RF signals output from a pickup being divided into a first divisional light reception part and a second divisional light reception part by a division line optically parallel to the tangential direction of an information track for receiving reflected light from the optical record medium, mark sections and space sections are clamped by potential correction circuits and a difference is found by a radial push-pull circuit.

Abstract: An optical disc which is a rewritable optical disc using a phase change medium or a magneto-optical (MO) medium, or a write once type optical disc using a pigment based medium, and has a track for recording user data, in which a wobble portion waved in a radial direction of the optical disc and a non-wobble portion that is not waved are provided on the track, first sub-information and second sub-information which are data other than the user data are recorded on the track by being overlapped, by using a combination of the wobble portion and the non-wobble portion, in the first sub-information, the length of at least one of the wobble portion and the non-wobble portion is different when a bit takes a logical value “0” and when the bit takes a logical value “1”, and in the second sub-information, the phase of a wave in the wobble portion when a bit takes a logical value “0” is different from the phase of a wave in the wobble portion when the bit takes a logical value “1

Abstract: Data read from a disk is input to an RF amplifier. An RF amplifier generates, based on bit data, an RF signal constituted by a plurality of components of mutually different frequencies. The RF amplifier determines a relation between the frequencies and gains on the basis of a control clock and adjusts the gains of respective components in the RF signals on the basis of the relation (equalize-processing). A PLL circuit has a first VCO and first frequency divider to generate a bit clock and generates, on the basis of an output signal of a data slice circuit, a first control voltage for controlling the first VCO. The first control voltage, being passed through a lowpass filter, is converted to a second control voltage for controlling a second VCO. The second VCO has an arrangement and characteristic substantially the same as those of the first VCO.

Abstract: An apparatus for reproducing information recorded on an optical disc which can favorably accomplish a time base correction for a read signal in a simple configuration. Also, the apparatus precisely removes jitter component produced when a read signal is converted to a predetermined encoded signal. The apparatus has a a spindle motor for rotating an optical disc, an optical pickup for optically reading a recorded signal on the optical disc to generate a read signal corresponding to the reproduced signal, and an A/D converter for digitizing the read signal to reproduce an encoded signal. The apparatus is provided with a signal processing unit for removing low frequency noise components from the read signal without producing distortions in the direction of the time base of the read signal in the processing prior to outputting the encoded signal in the A/D converter.

Abstract: A recording information reproducing apparatus which can precisely reproduce a digital signal from any one of a plurality of kinds of recording disks of different recording densities. A recording density of a recording medium as a reproduction target is detected and an amplitude of a high frequency component of a read signal read out from the recording medium is increased by a gain according to the detected recording density.