Abstract: A clock generator in a recorded information reproduction apparatus for reproducing recorded information from a recording medium includes a pickup that produces a reading signal by reading a recording track of the recording medium. The reading signal is sampled by a sampling circuit at timing corresponding to a clock signal to produce a reading sample value sequence. A crosstalk removing circuit removes crosstalk components which are present in recording tracks adjacent to the recording track read by the pickup from the reading sample value sequence and produces a crosstalk-removed reading sample value sequence. A phase detecting circuit detects a phase error existing in the reading signal based on the crosstalk-removed reading sample value sequence. A clock signal generating circuit generates the clock signal based on the phase error.

Abstract: A waveform equalizer which can improve an S/N ratio without causing a jitter in a read signal read out from a recording medium. An amplitude level of the read signal read out from the recording medium is limited by a predetermined amplitude limitation value and, thereafter, is subjected to a filtering process.

Abstract: A tilt detecting method which can accurately detect a tilt occurring between a recording disk and a pickup by a construction of a small scale. The reading position of the pickup for the center recording track among the three adjacent recording tracks formed on the recording surface of the recording disk is set to a reference. The tilt between the recording disk and the pickup is detected based on a differential value between a crosstalk from each of the positions which are displaced forward and rearward from the reading position on the recording track that is neighboring on the disk's outer rim side of the center recording track by a predetermined distance in the reading direction to the reading position and a crosstalk from each of the positions which are displaced forward and rearward from the reading position on the recording track that is neighboring on the disk's inner rim side by a predetermined distance in the reading direction to the reading position.

Abstract: A tilt detector for detecting a tilt which is present between a recording disk and a pickup. The tilt detector detects an error value between a read signal read from a central recording track within three recording tracks adjacent to each other and a predetermined value. A first coefficient is calculated from a correlation of a read signal read from the recording track adjacent to the central recording track on the inner peripheral side of the disk with the error value, and a second coefficient is calculated from a correlation of a read signal read from the recording track adjacent to the central recording track on the outer peripheral side of the disk with the error value. A tilt present between the recording disk and the pickup is detected on the basis of a relationship in magnitude between the first and second coefficients.

Abstract: A crosstalk eliminating method for use in a recorded information reproducing apparatus, which can eliminate crosstalks from the adjacent tracks of a recording track as a reading target even if a tilt occurs between a recording disk and a pickup. A reading position by the pickup for the center recording track among the three adjacent recording tracks is employed as a reference. Crosstalk components are obtained based on a read signal read out from each of the positions which are shifted by a predetermined distance frontward and rearward in the reading direction from the reading position on each of the recording tracks which are neighboring on both sides of the center recording track and a read signal read out from each position near the reading position on each of the recording tracks which are neighboring on both sides of the center recording track.

Abstract: A crosstalk removing device for use in a recorded information reproducing apparatus which is free from malfunctions even if a read sample value sequence, which has been read from a recording medium and sampled, is out of synchronization, and can immediately proceed to a crosstalk removing operation after the read sample value sequence recovers the synchronization. When crosstalk from adjacent tracks is removed from the read sample value sequence, which has been read from a recording medium and sampled, to produce a crosstalk removed read sample sequence, filter coefficients are derived for converging an error value present in the crosstalk removed read sample value sequence to zero, and the read sample value sequence is filtered on the basis of the filter coefficients to derive crosstalk components from the adjacent tracks. The crosstalk components are subtracted from the read sample value sequence to derive the crosstalk removed read sample value sequence.

Abstract: An apparatus for reproducing information recorded on a recording medium includes a signal reader for outputting signals read from a main track on the recording medium to be reproduced and for reading tracks adjacent to the main track. A variable filter for filtering the signal read from the adjacent track is also included to convert the signal into a crosstalk signal to the main track and a subtractor is utilized for subtracting the crosstalk signal from the signal read from the main track. The apparatus further includes a crosstalk signal corrector for correcting the level of the crosstalk signal based on the signal read from the main track.