Abstract: A digital playback signal detection apparatus includes a phase equalization circuit for compensating and correcting for loss of a low frequency band and phase distortion in the playback signal, respectively, a waveform shaper for correcting the waveform generated by the phase equalization circuit, and a data detector for detecting the originally recorded data using an output signal of the waveform shaper and a phase-inverted version thereof. The output of the phase equalizer circuit is delayed into first and second delay signals using two delays. The second delay signal and the output signal of the phase equalizer are amplified and differentiated, and then the differentiated signal and first delay signal are linearly added to each other. According to one aspect of the invention, the data detector compensates for loss of low-frequency band from a signal reproduced from a magnetic recording medium via an integrator in a phase equalizer.

Abstract: A fuzzy controller controls a track seeking operation and a track following operation for an actuator in accordance with a position error between a present position value and a reference value. When the actuator is in track seeking operation, the actuator is accelerated or decelerated based on a velocity error value between an actual velocity value of the actuator and a target velocity value determined from a velocity profile according to the position error. In a deceleration control of the actuator, a fuzzy inference value generated based on the velocity error value and its differentiated velocity error value is used for a control of the actuator, thereby reducing an occurrence of overshooting at a target track.

Abstract: A data reproducing apparatus reproduces a data recorded or medium which has auxiliary data added to main data subjected to an error correction coding process. The data reproducing apparatus includes a signal processor, a memory, a comparator and a controller. The signal processor separates the main data from the recording data read out from the recording medium to implement an error correction decoding process thereto. The memory means stores the decoded main data from the signal processor. The comparator compares the last data stored in the memory with the inputted main data to the memory. The controller controls write and read operations of the memory and controls the comparison condition of the comparator according to the main data from the signal processor.

Abstract: A disc drive system includes a plurality of subsystems. At least one of the subsystems includes a filter which is completely integrated using a synthetic integrated circuit element.

Abstract: An electronic architecture that provides a portable hard disk drive that can meet the type II PCMCIA specification and which can efficiently operate with a 3.3 V power supply.

Abstract: In accordance with the invention, a method for programing or editing, or both, the order of performance of digitally recorded information tracks, such as an audio recording, stored sequentially in an appropriate medium. The method allows a user to program or edit, via keystrokes, a program or sequence of tracks to be played. An apparatus for playing information tracks queued to be replayed in a predetermined sequence includes a key pad, which is used to enter commands and numeric information to establish a program queue, a display, which is used to display program events, and an interface processor, coupled to the key pad and the display, which is used to control the commands received from and sent to the key pad and to send display messages to the display. The apparatus also includes a control processor, coupled to the interface processor, which establishes from information stored on a medium in a sequential order, an ordered sequence of information tracks.

Abstract: A method for testing slider/disk contact in a disk drive is described. The disk drive comprises a rotating disk and a head mounted by an actuator for selective positioning of the head over the disk, the head having a slider, and a flexure for attaching the head to the actuator. The method includes the steps of rotating the disk of the disk drive at a first preselected rotational velocity, using the head of the disk drive to write a signal having a substantially uniform pattern on the disk as it rotates, thereafter rotating the disk at a second preselected rotational velocity, while rotating the disk at the second preselected rotational velocity, using the head to read back the signal written at the first preselected rotational velocity, and performing an FM demodulation of the read back signal through a frequency range corresponding to a range of natural frequencies of vibration of the flexure caused by slider/disk contact.

Abstract: An Alternating Current bias control circuit for a magnetic recording head which is suitable to be formed by an Integrated Circuit, wherein a band-pass filter for extracting an audio frequency signal component from a terminal voltage of the magnetic recording head and for supplying the audio frequency signal component to a peak detector is formed by a Resistor-Capacitor circuit. The input impedance of the band-pass filter is made high enough to reduce the power consumption, and the output impedance of the same is made low enough to facilitate impedance matching with the peak detector.

Abstract: A recording and/or reproducing apparatus for a disc shaped recording medium having a first recording region in which an information signal is recorded using pits and a second recording region in which an information signal is recorded using a magneto-optical method includes a rotational driving unit, a servo apparatus and a controller. A head moves between the first and second recording regions of the disc-shaped recording medium and records and reproduces information signals to and from the disc-shaped recording medium. The rotational driving unit rotates the disc-shaped recording medium at a constant linear velocity by using the output signal outputted from the head. The servo apparatus generates a servo signal according to an error signal generated using the output signal from the head and carries out servo control on the head and the rotational driving unit.

Abstract: A digital video tape recording method for trick play includes the steps of dividing the data area of a video sector of respective tracks of the digital video tape into first, second and third regions, interspersely recording normal play data and trick play data in the first and third regions, and recording the normal play data in the second region, wherein the trick play data recorded in the first and third regions is frame data corresponding to the maximum odd-fold speed of a plurality of given odd-fold speeds, and the same trick play data is repeatedly recorded for a number of tracks equal to twice the number of the maximum odd-fold speed, thereby enabling satisfactory trick play at various odd-fold speeds and with various scanners.

Abstract: The invention is used in a disk drive and comprises a feedforward circuit connected between the head position circuit and the speed control loop circuit. The feedforward circuit precompensates the speed control loop for changes in rotation drag due to movements in the head of a disk drive. The feedforward circuit may include one or more deadband amplifiers and may include filter circuit. The invention disclose the method for controlling the speed of a spindle motor in a disk drive which includes the step of precompensating the speed control loop circuit with a processed head positioning signal.

Abstract: An adaptive predictor for use with a control system to predict error contributions due to harmonic distortion in a error signal such that the prediction signal may be fed back and added to the error signal to compensate for the harmonic distortion. The adaptive predictor takes the error signal representative of misposition error and performs a discrete Fourier analysis to determine contributions due to individual harmonics. It then adjusts the results and tallies a running total thereby adapting to a mechanical system in which it is contained. The running total is combined with a carrier signal which is clocked to produce a predictive signal representing harmonic distortion at a given time. The predictive signal is then added back with the original error signal to produce a harmonic distortion compensated signal.

Abstract: A no-ID zone-bit-recording sectored servo data recording disk drive system is described wherein track seek time is substantially reduced by storing only partial cylinder address on each servo sector of each track. According to the system and method described herein, a cylinder address is divided into high order bits, middle order bits, and low order bits. The low order bits is stored on each servo sector of each track. The high order bits is stored only on even number servo sectors and middle order bits is stored only on odd number servo sectors. During the seek operation, as the head passes over the tracks toward the desired track, the partial cylinder address stored on odd and even numbered servo sectors on each track is retrieved and stitched together to form a complete cylinder address. The completed cylinder address is then compared with the desired cylinder address to determine whether desired cylinder is reached or not.

Abstract: Control system/method for controlling disk spindle motor speed in a disk drive system using transducers riding or flying upon the disks, with a viscous substance between the disks and the transducers thereby exerting a load upon the spindle motor, the load having a non-uniform profile from the disk inner diameter to the outer diameter where the load at any location across the disk is a function of the medium upon which the transducers ride or fly above the disks, the location itself and the physical environment being experienced by the medium at any given instant of time. The control system provides speed control data that defines the power applied to the spindle motor to maintain a desired motor speed as a function of the presently selected track address and a controller that provides and selects for a presently selected track address the speed control data to the spindle control system to maintain the spindle motor speed at the specified speed.

Abstract: A recorded data securing mechanism secures data recorded on a recording medium cassette provided with a memory and a data recording enable/disable tab at a predetermined position on the cassette. Breaking the recording enable/disable tab provided on the memory-based recording medium cassette prevents data recorded on the cassette from being written over and ensures that there will be no mismatch between the recording information stored in the memory of the cassette and the data recorded on the recording medium of the cassette. In one embodiment, rewriting is enabled but a memory mismatch flag is set if rewriting results in a mismatch.

Abstract: In a disk drive using a write-wide inductive write element and a read-narrow magneto-resistive read element within a head transducer assembly for writing and reading magnetic patterns on a rotating magnetic storage disk in a plurality of concentric tracks, a track pattern formed in each concentric track includes embedded servo wedges wherein each wedge includes a servo position portion which is offset from a centerline of both the servo sector and a following user data sector by an amount related to offset between the inductive write and magneto-resistive elements of the head transducer assembly. Furthermore, the servo sector contains four servo bursts. The servo bursts are arranged such that each sequential burst is offset from a previous burst by a fractional offset increment. The fractional offset increment is typically one-third of a track pitch.

Abstract: A magnetic head driving device is disclosed. The device includes an inductor for generating a magnetic field, the inductor having a pair of terminals. The device has a first auxiliary coil for storing electromagnetic energy, the first auxiliary coil being connected to one of the terminals of the inductor at a first node, second auxiliary coil for storing electromagnetic energy, the second auxiliary coil being connected to the other terminal of the inductor at a second node, first main switch connected to the first node, second main switch connected to the second node, and control circuit for receiving a first signal indicating generation of a magnetic field by the inductor and a second signal indicating the direction of a magnetic field generated by the inductor and for outputting the second signal for a predetermined period of time in accordance with the first signal to alternately turn on or off the first main switch and the second main switch.

Abstract: In an optical recording medium on which the main information is recorded on a pre-formed recording track along the track direction and in which the recorded data are read out by optical means, frame sync signals based on the same format as the format for the main information are pre-recorded by offsetting the recording track itself along its width for each frame as an information recording unit, for facilitating frame synchronization and simplifying the construction through the use of a sole common synchronizing circuit. The information pre-recorded by offsetting the track itself along its width includes not only the frame sync signals but also any reproduce-only information for increasing the disc recording capacity.

Abstract: A digital servo control system for controlling a disk file head includes a main control loop at least one head for reading servo information; a voice coil motor (VCM) attached to the head for positioning the head relative to the target track centerline of a track in response to a VCM control signal; means for deriving from the servo information a digital head position error signal (PES); and a processor employing an estimator model for estimating parameters of the VCM and for generating from the estimated parameters and the digital VCM control signal. A secondary control loop receives the PES and provides a compensation signal for repeatable runout (RRO) by providing high open-loop gain near the spindle rotation frequency of said disk. The compensation signal for repeatable runout (RRO) is added to VCM control signal. The secondary control loop includes two states x.sub.a and x.sub.b with state equations x.sub.a (k)=x.sub.b (k-1)-k.sub.1r e(k) and x.sub.b (k)=2 cos .omega.Tx.sub.a (k)-x.sub.a (k-1)-k.sub.

Abstract: In a sampled amplitude magnetic read channel, pulses in an analog signal corresponding to flux transitions on a magnetic medium are sampled and equalized into a first equalization for estimating sample values and into a second equalization for sequence detection of digital data. A gain and phase error detector generate respective error signals corresponding to the difference between estimated and actual sample values. Gain control and timing recovery use the error signals to adjust the amplitude and sampling frequency/phase of the analog read signal. A pair of programmable discrete time filters equalize the signal samples into the desired equalization. In a first embodiment, the signal samples are equalized to PR4 for estimating sample values and to EPR4 for sequence detection. A slicer processes the PR4 equalized sample values to generate the estimated sample values.