Abstract: A clock generator applicable to a sample servo type magnetic disk drive is disclosed. Reproduced signals z(t) from a clock pattern are digitized by an A/D converter (33) before being fed to a phase comparator (52). An arithmetic unit (61) calculates an inner product of N sampled values and N weighting factors in a linear combination, and a D flip-flop (62) provides a phase comparison error signal f(&thgr;). The signal f(&thgr;) is converted by a D/A converter (53) to analog format before being supplied as a control signal to a VCO (51) via a loop filter (54). A clock signal CLK from the VCO (51) is controlled in phase so as to generate a clock signal CLK synchronized with the reproduced signals z(t). When the weighting factors are arranged so that their total sum becomes zero, the signal f(&thgr;) is free from adverse effects of DC elements superposed on the reproduced signals z(t), whereby a clock signal CLK in precise synchronism with the reproduced signal z(t) is obtained.

Abstract: A digital signal processing circuit comprising a memory means for storing a digital signal obtained from a playback channel; a control means for writing the digital signal in the memory means at a first rate and reading out the digital signal from the memory means at a second rate lower than the first rate; and a processing means for executing a desired process relative to the digital signal thus read out from the memory means. The digital signal is written in the memory means at a first rate by the memory control means and is read out therefrom at a second rate lower than the first rate. And then a desired signal process is executed relative to the digital signal read out from the memory means. Therefore the required digital processing rate becomes lower than the transmission rate of the playback channel, whereby the transmission rate can be raised despite the condition that the time required for the desired signal process such as demodulation is rendered longer.

Abstract: A digital magnetic reproducing apparatus comprises a reproducing head to reproduce data from a magnetic recording medium; an equalizer for shaping, by a partial response method, the waveform of the reproduced signal outputted from the reproducing head; and a decoder for decoding, by a maximum likelihood decoding method, the equalized reproduced signal obtained from the equalizer. The reproducing head employed in this apparatus is an MR (magnetoresistance effect) head which is capable of reducing the second harmonic distortion of the reproduced signal to be -25 dB or lower. Therefore the deterioration of the bit error rate that may result from the nonlinear distortion of the MR head can be further lowered within a sufficiently suppressed range in practical use.

Abstract: A digital magnetic reproducing apparatus comprises a reproducing head to reproduce data from a magnetic recording medium; an equalizer for shaping, by a partial response method, the waveform of the reproduced signal outputted from the reproducing head; and a decoder for decoding, by a maximum likelihood decoding method, the equalized reproduced signal obtained from the equalizer. The reproducing head employed in this apparatus is an MR (magnetoresistance effect) head which is capable of reducing the second harmonic distortion of the reproduced signal to be -25 dB or lower. Therefore the deterioration of the bit error rate that may result from the nonlinear distortion of the MR head can be further lowered within a sufficiently suppressed range in practical use.

Abstract: A highly reliable magnetic recording and playback apparatus utilizes an independent magnetic clock pattern region and a pattern set region to provide a common timing reference between a data recording region and its adjacent tracks. In the apparatus, the pattern set region provides a reference point so that the circumferential location of the magnetic pattern region can be determined. In one embodiment, the apparatus includes elements for playback of reproduced information recorded on a magnetic disk and an arrangement which provides for the generation of a data existing point clock.

Abstract: A highly reliable magnetic record playback apparatus utilizes an independent magnetic clock pattern region and a pattern set region to provide a common timing reference between a data recording region and its adjacent tracks. In the apparatus, the pattern set region provides a reference point so that the circumferential location of the magnetic pattern region can be determined. In one embodiment, the apparatus includes elements for playback of reproduced information recorded on a magnetic disk and an arrangement which provides for the generation of a data existing point clock.

Abstract: A magnetic disc having a ROM area and a RAM area which are separated. The ROM only plane and the RAM only plane are separated on the magnetic disc.

Abstract: To increase the recording capacity of a magnetic disc, tracks of this magnetic disc are divided into a number of sectors, with each sector being formed from a number of segments. Each segment is basically made up of a data region and a servo region with data being recorded on the data region and a clock pattern which becomes the basis for generation of a clock, a fine pattern which becomes the basis for the tracking operation, and an access pattern which becomes the basis for a seek operation being recorded on the servo region. An ID region and servo region are formed before the data region and servo region which make up the leading segment with the sector ID for this region being recorded in this ID region. After this ID has been read from this ID region, while it is being determined whether or not this ID is the same as the designated ID, the servo operation corresponding to the servo control signal occurring in the servo region is carried out.

Abstract: A highly reliable magnetic recording and playback apparatus utilizes an independent magnetic clock pattern region and a pattern set region to provide a common timing reference between a data recording region and its adjacent tracks. In the apparatus, the pattern set region provides a reference point so that the circumferential location of the magnetic pattern region can be determined. In one embodiment, the apparatus includes elements for playback of reproduced information recorded on a magnetic disk and an arrangement which provides for the generation of a data existing point clock.

Abstract: There is disclosed a magnetic disk device of the external synchronization system using a head assembly of the recording/reproducing heads separation type. This magnetic device comprises: a reproducing head for reproducing data from a magnetic disk; a clock signal generator for generating a clock signal on the basis of a reproduced signal corresponding to a clock pattern from the reproducing head; a delay circuit for delaying recording data relative to the clock signal generated at the clock signal generator; a recording head for recording the recording data delayed by the delay circuit onto the magnetic disk; a position detecting circuit for detecting head position information (e.g.

Abstract: A disk drive for magnetic disk of the sample servo type, having N (N.gtoreq.200) servo areas, wherein the product of N and the recording/reproduction mode switching time Th (.mu.s) of the head amplifiers, i.e., N.times.Th, is designed to be 1200 or smaller.

Abstract: A clock reproducing apparatus is adapted for reproducing a data existing point clock signal by using a reproduction signal obtained from a magnetic disc on which clock patterns for clock reproduction are recorded in servo areas discretely provided independent of data recording area, which comprises: a voltage controlled oscillator operative to oscillate the data existing point clock signal; a sampling circuit for sampling the reproduction signal in synchronism with the data existing point clock signal; a phase information generator for weighting-adding plural sample values before and after a reference sample value corresponding to the peak of a reproduced isolated waveform of the clock pattern to thereby generate phase information indicating a phase difference between the data existing point clock signal and a reproduction signal of the clock pattern; and a control voltage converter for converting phase information generated by the phase information generator to a control voltage for controlling the voltage c

Abstract: A data detecting apparatus for detecting desired data from a digital signal comprising a first sampling circuit for sampling the digital signal to output samples, an interpolating circuit for interpolating signal values between the samples outputted from the first sampling circuit, and a second sampling circuit for extracting those signal values interpolated by the interpolating circuit which match a phase of a point at which the desired data exists. This constitution allows to implement all blocks making up the data detecting apparatus with digital signal processing circuits synchronously operating on the a clock, detecting the reproduced signal data without being affected by jitters contained in reproduced signals coming from a channel. The constitution also makes it possible to form on a single LSI chip such circuits including the data detecting apparatus, an ECC decoder, a controller, and an interface circuit as conventionally formed on discrete chips.

Abstract: A decision-directed phase-locked loop for not synchronizing with opposite phases where the proper data of a PRS channel reproduced signal do not exist. The loop comprises a digital loop filter, a ternary level predicting portion, a phase modification signal generating portion and an instantaneous phase detecting portion. The phase value of a future data existing point is first obtained on the basis of the phase value of the current data existing point in a reproduced signal output from the digital loop filter. The ternary level predicting portion predicts future data of the reproduced signal based on the phase value of the future data existing point and on future sampled values of the reproduced signal. Given the predicted future data, the phase modification signal generating portion checks to see if the current zero cross point of the reproduced signal is a data existing point.

Abstract: An analog/digital compatible reproducing system is disclosed, particularly a stationary head system using a digital recorded magnetic tape having a plurality of n, digital data recorded tracks. An analog recorded magnetic tape has a first analog recorded track and a second analog recorded track between which a guardband of a certain width is provided. Signals are reproduced from the digital recorded magnetic tape by driving n reproducing magnetic head elements respectively corresponding to the n digital data recorded tracks. The analog recorded magnetic tape is reproduced by driving a plurality of m reproducing magnetic head elements of said n reproducing, magnetic head elements, corresponding to the first and second recorded tracks so that common outputs can be produced from the m reproducing magnetic head elements. There is also disclosed a tape cassette used in such system.

Abstract: A combination magnetic transducer head apparatus which can easily achieve initial formatting of data tracks of a rotating magnetic recording medium such as a hard disk without using a specific separate initial formatting system. The apparatus comprises a magnetic head for initial formatting, another magnetic head for servo control and a magnetic recording and playback head all mounted on a head slider. In the apparatus, at least one track is first recorded on a magnetic disk by the magnetic head for initial formatting and then another track is recorded by the magnetic recording and playback head while the first track is scanned by the magnetic head for servo control whereafter such a series of operations are repeated until completion of recording of all tracks required.

Abstract: A servo system for positioning a data transducer head relative to a plurality of substantially concentric data tracks on the surface of a magnetic disc including a pair of servo transducer heads for sensing the data tracks and generating output signals representative of a data signal written on the sensed track, a distance between the pair of servo transducer heads being related to the dimension of the data track and a distance between the servo transducer heads and the data transducer head being related to a data track pitch, a signal processing circuit connected to the pair of servo transducer heads for generating a data transducer head positioning signal and a positioning device for positioning the data transducer head in response to the transducer positioning signal and for maintaining the track centerline alignment of the data transducer head.

Abstract: A digital data detecting apparatus comprises means for sampling an input digital signal at a frequency which is M times (M>1) higher than a channel bit rate, means responsive to two adjacent sampled values for computing an interval from a point where the digital signal intersects a reference level to a sampling time, and means responsive to an output from the computing means for generating a data detecting signal for detecting data of the digital signal.