Abstract: A digital signal reproducing apparatus has the clock signal generating device 24 having: a frequency setting device 12 for setting a desired frequency on the basis of the predetermined linear velocity and a radius position of a pickup 1; a first frequency difference signal generating device 242 for generating a binary signal E corresponding to a difference between the desired frequency fsd and the frequency fs of the sample clock signal A to be used for reproducing a reproduction digital signal; a second frequency difference signal generating device 243 for generating a pulse signal L corresponding to a difference between the frequency based on the reproduction digital signal and the frequency fs of the sample clock signal A; a phase difference signal generating device 244 for generating a pulse signal Y corresponding to a difference between the phase based on the reading signal read from the disc and the phase of the sample clock signal A; and a synchronizing device 24 for synchronizing the frequency fs and

Abstract: A recorded information reproducing apparatus is capable of highly reliably reproducing information even from a recording medium on which recorded information including recorded signals in a low frequency band are recorded at a high density. An error voltage is subtracted from an analog read signal read from a recording medium to generate a corrected read signal. The corrected read signal is sampled to be converted into a digital corrected read sample sequence from which recorded information is decoded. Here, the sample existing at a position nearest to each zero-cross point in the corrected read sample sequence is extracted from the corrected read sample sequence to generate an extracted sample sequence. Each sample in the extracted sample sequence is converted into an analog signal having a level corresponding to the associated sample value. This analog signal is used as the above error voltage.

Abstract: A crosstalk canceler cancels crosstalk components mixed into a reproduced signal of a target track from a first and a second neighboring tracks positioned on both sides of the target track formed on an optical disc.

Abstract: A digital signal reproducing apparatus which can reproduce a digital signal by a sampling clock that is accurately synchronized with a phase of a read signal. A sample value near the zero level is extracted from a sample value sequence obtained by sampling the read signal. When a sample value level of the sample value sequence has a rising tendency, a sampling clock whose phase is corrected on the basis of one of the extracted sample value and an inversion extracted sample value obtained by inverting a polarity of the extracted sample value is generated. When the sample value level of the sample value sequence has a falling tendency, a sampling clock whose phase is corrected on the basis of the other one of the extracted sample value and the inversion extracted sample value is generated.

Abstract: An optical disk player for compensating a waveform distortion of a read signal which is caused due to a skew in the track tangential direction of an optical disk. An optical disk is constructed in a manner such that a skew amount of the irradiated portion of a recording surface of the optical disk for a light beam irradiated onto the recording surface of the optical disk is detected from the pickup and transmitting characteristics of a read signal generated from the pickup are controlled in accordance with the detected skew amount. A waveform distortion of the read signal due to a warp or distortion existing in the track tangential direction of the optical disk can be compensated and the recording data can be accurately reproduced.

Abstract: A digital data reproducing apparatus performs an accurate data decoding by appropriately correcting a phase error as well as a level error in sample values of a read signal. When a sampling value with an absolute value smaller than a specified value is extracted from a sample value series of the read signal successively outputted from an A converter according to a timing of a sampling clock pulse, the value is obtained as an extracted value and also a slant signal indicating a positive or negative sign of a slant in a portion corresponding to the extracted sample value in the sample value series is obtained, and a phase in the sampling clock pulse is corrected according to the extracted sample value as well as the slant signal, and also a level of an output sample value from the A/D converter is corrected according to the extracted sample value, and digital data according to the sample value subjected to the level correction is decoded.

Abstract: A digital PLL circuit in a recording information reproducing apparatus, wherein a sampled value is obtained by A/D converting a read signal read from a recording medium at a sampling timing according to a reproduction clock signal, a phase error occurring in the read signal is detected on the basis of the sampled value, an oscillation data signal sequence whose data value increases or decreases at a changing period corresponding to the phase error is generated, the oscillation data signal sequence is converted to an analog signal, an oscillation signal is formed, and a signal obtained by converting the oscillation signal to a square wave is set to a reproduction clock signal for sampling.

Abstract: An encoded digital signal reproducing apparatus in which a read signal from a recording medium is compared with each of thresholds different from each other to generate at least two binary-coded signals. When a first predetermined code train pattern is detected from one of the two binary-coded signals and a second predetermined code train pattern is simultaneously detected from the other of the two binary-coded signals, a frame synchronization detection signal is generated. A data signal is then decoded from the read signal on the basis of the timing at which the frame synchronization detection signal is generated. Thus, the probability of erroneous detection of the frame synchronization signal is reduced even with a high recording density, thus making it possible to correctly detect the frame synchronization signal.

Abstract: A digital signal reproducing apparatus which is capable of accurately reproducing a digital signal from a recording medium on which signals are recorded at a high density. A read signal outputted from a pickup is converted into a binary signal which is synchronized to produce a synchronized binary signal. From this synchronized binary signal, a synchronized short pulse binary signal portion is detected which has an inversion interval shorter than a predetermined period and thus may violate a run length limit. The apparatus determines whether the center position on the time base of the short pulse binary signal portion before synchronization is closer to the sampling timing existing immediately before the short pulse binary signal portion or closer to the sampling timing existing immediately after the short pulse binary signal portion. The logic of the synchronized binary signal at the sampling timing determined as being closer is inverted to correct erroneously read data.