Abstract: An instantaneous jitter information detection section detects, based on first and second digital values indicating different polarities relative to a predetermined reference value, an instantaneous gradient value corresponding to a difference value between the first and second digital values, and an instantaneous deviation value corresponding to a difference value between an intermediate value between the first and second digital values and the reference value. An information conversion section converts, based on an inversely proportional conversion table, the instantaneous gradient value to an inversely proportional value. An arithmetic section detects an instantaneous variance value by multiplying the instantaneous deviation value and the inversely proportional value together, and squaring a value obtained by the multiplication, and detects an integrated value by accumulating the instantaneous variance value.

Abstract: A parallel interpolation A/D converter includes a reference voltage generation circuit configured to generate (m+1) different reference voltages VR1-VRm+1, where m is a positive integer, and VR1<VR2, . . . , <VRm<VRm+1, a differential amplifier series including (m+1) differential amplifiers A1-Am+1 configured to amplify voltage differences between the reference voltages VR1-VRm+1 and an input signal voltage, and an operation circuit including a plurality of comparator circuits configured to receive output voltage sets generated by the respective differential amplifiers. The number of comparator circuits varies depending on the value k of the reference voltage VRk, where k is an integer of 2?k?m+1.

Abstract: An instantaneous jitter information detection section detects, based on first and second digital values indicating different polarities relative to a predetermined reference value, an instantaneous gradient value corresponding to a difference value between the first and second digital values, and an instantaneous deviation value corresponding to a difference value between an intermediate value between the first and second digital values and the reference value. An information conversion section converts, based on an inversely proportional conversion table, the instantaneous gradient value to an inversely proportional value. An arithmetic section detects an instantaneous variance value by multiplying the instantaneous deviation value and the inversely proportional value together, and squaring a value obtained by the multiplication, and detects an integrated value by accumulating the instantaneous variance value.

Abstract: A signal processing device, even when a steep difference in DC level is included in a signal read from a disc such as a DVD-RAM format, cuts off the DC level and pulls the read signal into an appropriate A/D input level. A steep difference in DC level between a data section and a CAPA section is absorbed by a first offset unit, and an asymmetry which occurs due to variations in the disc manufacturing stage is corrected by a second offset unit. Further, a control signal for operating the two offset units exclusively is generated by a controller, thereby controlling both offset units.

Abstract: An information reproduction device according to the present invention is a device for accessing a recording medium having first address information and second address information recorded thereon. The first address information is represented by a shape formed on the recording medium in advance; and the second address information is recorded on the recording medium together with data. The information reproduction device includes a head section for accessing the recording medium to generate a reproduction signal; a first detection section for detecting the first address information from the reproduction signal; a second detection section for detecting the second address information from the reproduction signal; and a control section for, based on a detection result of either the first detection section or the second detection section which detected the address information first, controlling an access after the detection to the recording medium.

Abstract: A digital signal reproducing apparatus includes an analog to digital converter for sampling and quantizing a signal read from an optical recording medium in accordance with a reproduced clock having a frequency which is one-half of a channel bit frequency and outputting an obtained digital RF signal, an offset compensation circuit for reducing an offset component in an amplitude direction from the digital RF signal, and a simplified interpolation filter for reconstructing a signal indicating a predetermined pattern recorded in the optical recording medium from the output signal of the offset compensation circuit and outputting the reconstructed signal. A control operation is performed to reduce the magnitudes of respective values shown by first phase error information on a section with the predetermined pattern and by second phase error information on a section other than the section with the predetermined pattern.

Abstract: A waveform equalization control device includes a waveform equalizer that has a filter provided with a plurality of taps, updates the tap coefficient of each of the plurality of taps in accordance with a tap coefficient signal inputted thereto, causes the plurality of taps to respectively receive a plurality of values sampled at different time points from an input signal, performs waveform equalization with respect to the input signal, and outputs the signal after the waveform equalization, an equalization target value generation unit for determining an equalization target value, an error estimation unit for obtaining the error between the equalization target value and the signal after the waveform equalization, and a coefficient update unit for determining an amount of updating the coefficient of each of the taps of the filter of the waveform equalizer based on the error signal and on the input value to each of the taps and outputting the amount of updating the tap coefficient as the tap coefficient signal.

Abstract: It is an object of the present invention to provide a signal processing device which, even when a steep difference in DC level is included in a signal read from a disc such as a DVD-RAM format, cuts off the DC level and pulls the read signal into an appropriate A/D input level with an attempt to cost reduction. A steep difference in DC level between a data section and a CAPA section is absorbed by a first offset unit 1, and an asymmetry which occurs due to variations in the disc manufacturing stage is corrected by a second offset unit 2. Further, a control signal for operating the two offset units exclusively is generated by a controller 7, thereby to control the both offset units.

Abstract: There is provided an optical disc device which can evaluate in a short time as to whether an optical disc is recorded with satisfying the standard or not. An optical disc device for measuring a recording deviation amount of data recorded on an optical disc on which physical addresses are previously provided, includes an address detection circuit which detects the physical address and outputs a physical address detection signal, a timer which is operated in synchronization with reproduced data from the optical disc, a recording deviation amount measurement circuit which measures the recording deviation amount of data recorded on the optical disc by using the physical address detection signal and the count value of the timer, a memory which stores the measured recording deviation amount, and a data transfer circuit which transfers the recording deviation amount to the memory.

Abstract: A digital signal reproducing apparatus includes an analog to digital converter for sampling and quantizing a signal read from an optical recording medium in accordance with a reproduced clock having a frequency which is one-half of a channel bit frequency and outputting an obtained digital RF signal, an offset compensation circuit for reducing an offset component in an amplitude direction from the digital RF signal, and a simplified interpolation filter for reconstructing a signal indicating a predetermined pattern recorded in the optical recording medium from the output signal of the offset compensation circuit and outputting the reconstructed signal. A control operation is performed to reduce the magnitudes of respective values shown by first phase error information on a section with the predetermined pattern and by second phase error information on a section other than the section with the predetermined pattern.

Abstract: After a playback RF signal 3 detected from an optical disc medium 1 is waveform-shaped, it is converted into a digital RF signal 6 with a sampling clock 8 having a cycle twice as long as a channel clock. Thereafter, a first offset correction circuit 9 corrects an offset fluctuation in a high frequency band, and a digital adaptive equalizer 23 performs adaptive equalization, and then a second offset correction circuit 27 corrects an offset component that remains after the offset correction by the first offset correction circuit 9, thereby demodulating a digital binary signal 37. Therefore, even when high-speed playback is carried out and an asymmetry depending on the recording quality is large, a reduction in power consumption can be realized while maintaining high-performance playback. Consequently, it is possible to provide an optical disc playback apparatus which can realize sufficient playback performance at low power consumption.

Abstract: An optical disc recording/playback apparatus is provided with a first AD converter 35 for shaping a push-pull signal 14 detected from an optical disc medium 1 by a light difference signal shaping circuit 21, and converting the signal into a digital sampling signal 38 using a sampling clock 37 synchronized with a channel frequency; a series of means for detecting wobble amplitude information 77 during recording from the digital sampling signal 38; a series of means for detecting address polarity information 60 and address position information during playback; and a recording laser power control circuit 113 for controlling a recording laser power to a power suited for recording on the basis of the wobble amplitude information.

Abstract: An optical disk device is provided with a first analog-to-digital converter for converting a push-pull signal detected from an optical disc medium into a digital sampling signal according to a sampling clock in the vicinity of a channel frequency. The optical disk device also includes an address polarity information detection circuit for detecting address polarity information from the digital sampling signal, and an address position information detection circuit for detecting address position information from the digital sampling signal while maintaining continuity.

Abstract: When generating a sampling clock of an A/D converter for digitizing a playback signal from an optical disc, an over sampling clock generated by a PLL is used. Further, zerocross position information and reference information of a playback digital signal that is obtained by A/D conversion using the over sampling clock are converted into those synchronized with the channel bit clock by an operation cycle conversion unit, and then supplied to a PRML signal processing unit and a level judgement binarization unit.

Abstract: A waveform equalization control device includes a waveform equalizer that has a filter provided with a plurality of taps, updates the tap coefficient of each of the plurality of taps in accordance with a tap coefficient signal inputted thereto, causes the plurality of taps to respectively receive a plurality of values sampled at different time points from an input signal, performs waveform equalization with respect to the input signal, and outputs the signal after the waveform equalization, an equalization target value generation unit for determining an equalization target value, an error estimation unit for obtaining the error between the equalization target value and the signal after the waveform equalization, and a coefficient update unit for determining an amount of updating the coefficient of each of the taps of the filter of the waveform equalizer based on the error signal and on the input value to each of the taps and outputting the amount of updating the tap coefficient as the tap coefficient signal.

Abstract: An information reproduction device according to the present invention is a device for accessing a recording medium having first address information and second address information recorded thereon. The first address information is represented by a shape formed on the recording medium in advance; and the second address information is recorded on the recording medium together with data. The information reproduction device includes a head section for accessing the recording medium to generate a reproduction signal; a first detection section for detecting the first address information from the reproduction signal; a second detection section for detecting the second address information from the reproduction signal; and a control section for, based on a detection result of either the first detection section or the second detection section which detected the address information first, controlling an access after the detection to the recording medium.

Abstract: In a jitter detection apparatus, a playback RF signal 3 detected from an optical disc medium 1 is subjected to waveform shaping, and thereafter, converted into a digital RF signal 6 with a sampling clock having a cycle twice as long as a cycle of a channel clock. Thereafter, an offset variation in a high-frequency band is corrected by an offset correction circuit 9, and data that are missing in the time direction are restored by a Nyquist interpolation filter 23. Then, positions where jitter is to be extracted are selected from an output signal of the Nyquist interpolation filter 23, by a jitter detection preprocessing circuit 28, according to the playback speed of the optical disc medium 1 and the arithmetic capacity of a digital signal operation circuit 29, whereby highly accurate jitters can be extracted by using the digital signal operation circuit 29.

Abstract: An information reproduction apparatus and method according to the present invention are provided so as to solve the problem that signal quality is degraded in a normal signal part when always performing a correction of a transient in reproducing information recorded in a medium, and the sag cancellation controller (103) detects whether the pickup output signal (S101) is normal or abnormal, and the sag cancellation part (104) performs a correction of a transient only during a period when the pickup output signal (S101) is detected as abnormal, thereby preventing degradation of signal quality, which is caused by performing a correction of a transient on a normal signal part, and an appropriate correction of a transient can be performed on an abnormal signal part, thereby enabling a stable reproduced signal (S104) to be obtained.

Abstract: An optical disc device of the present invention obtains a reproduction quality that is independent of a mark distortion by receiving a signal that is obtained from an A/D converter for digitizing a reproduction signal of an optical disc medium and an offset correction means for performing offset correction, accurately measuring a mark distortion factor in a mark pattern having a long recording width by means of a mark distortion factor measuring means, and selecting one of output signals from a PRML signal processing means and a level judge binarization means by means of a digital data demodulation selection means by utilizing the measured mark distortion factor as a judgement criterion, to be used as a demodulation binary signal.

Abstract: The present invention is made to improve the conventional analog processing that is easily affected by variations in semiconductor processing. This invention provides a wobble signal processing apparatus that can reduce the circuit scale and the power consumption as well as improve the quality of signal processing. The wobble signal processing apparatus of the present invention digitally processes a part that has conventionally been processed by an analog system, and a PRML circuit is further provided to implement error detection, whereby the circuit scale and the power consumption is reduced. This improves the detection of a signal that is inputted to the wobble signal processing apparatus.