Abstract: The present invention relates to apparatus for reading and writing data to a storage medium, wherein the data is written to the medium in tracks, each track having a predetermined trigger signal pattern, the apparatus comprising: structure for detecting the predetermined trigger signal pattern; an adaptive filter for signals read from the medium; and structure for triggering adaptive filtering for a track of data on detection of the predetermined trigger signal pattern in that track. In this way, during a read operation adaptive filtering is triggered on commencement of data with spectral characteristics suitable for adaption of the filter. In the embodiment to be described, each track comprises data fragments each having a header containing ancillary information wherein at least a header in an initial data fragment in the track comprises the predetermined trigger signal pattern. Preferably, at least the header of the initial data fragment in the track comprises the predetermined trigger signal pattern.

Abstract: A recording information reproducing apparatus which can precisely reproduce a digital signal from any one of a plurality of kinds of recording disks of different recording densities. A recording density of a recording medium as a reproduction target is detected and an amplitude of a high frequency component of a read signal read out from the recording medium is increased by a gain according to the detected recording density.

Abstract: A voice recording/playback apparatus includes a head unit which records a voice signal in a recording medium and for playing back a recorded voice signal from the recording medium. A playback head amplifier unit amplifies a playback signal output from the head unit. A voice output unit outputs a voice in accordance with the playback signal amplified by the playback head amplifier unit. A muting switch is provided between the playback head amplifier unit and the voice output unit. The muting switch cuts off a connection between the playback head amplifier unit and the voice output unit when a voice recording mode is performed by the head unit.

Abstract: In a data recording system used for a magnetic disk drive, a write amplifier feeds a write head with a recording current that corresponds to the data to be recorded on the disk. A recording current controller selects a current value to be fed to the write head from the write amplifier according to the recording pattern detected by a pattern detection circuit. Thus, an effective recording track width can be selected without relying on the recording wavelength of the data to be recorded. Therefore, the influence of the cross talk from adjacently located tracks can be effectively reduced without unnecessarily reducing the recording track width.

Abstract: A digital signal recording apparatus includes an amble generator for generating an amble signal representing a bit-sequence amble pattern. The bit-sequence amble patter can be detected and reproduced by a partial-response detection system “PR(1, 0, −1)” as a detected amble pattern having a period of state inversions which is shorter than a period of state inversions in a detected amble pattern corresponding to a recorded amble pattern of alternation of “1” and “0”. The amble signal generated by the amble generator and a first digital information signal are combined into a second digital information signal on a time sharing basis. The second digital information signal is recorded on a magnetic recording medium. For example, the bit-sequence amble pattern represented by the amble signal has repetition of six bits of “111000”.

Abstract: A mass storage peripheral device for use with a host computer has a rotating data medium with a motor arranged to rotate it. A sensor reads information from the medium, and a data preamplifier for amplifies the read information. An interface is connected between the mass storage peripheral device and the associated computer. The interface includes a data transmission path to conduct data signals from the data amplifier to a controller circuit for the peripheral device in the host computer. The mass storage peripheral device may also include a circuit path to receive motor control and drive signals from the host computer for operating the motor. The peripheral device may be adapted to receive motor control signals from a servo circuit, which is preferably located in the host computer and connected to the interface for operating the motor. A read channel circuit is connected to receive the amplified data signal, also may be located in the host computer.

Abstract: A method and apparatus for improving a thermal response of a (magnetoresistive) MR element. In one embodiment, the thermal response is improved by reducing the heat transfer from the MR element to a shield layer. For example, an insulation layer between the MR element and the shield layer may be a material having a lower thermal conductivity than is conventional. In another embodiment, the thermal response is improved by controlling the heating of the MR element based on feedback signal from the MR element, for example, a thermal signal and/or a magnetic or thermal spacing signal. The controlled heating of the MR element may be provided by a heating element, a write element, and/or MR bias current, for example.

Abstract: A writing unit divides a sync byte into two sync bytes of a first sync byte and a second sync byte and also divides write data into two data of first data and second data and writes them. When a first sync byte pattern is detected, a reading unit demodulates the subsequent first data, second data, and an error detection correction code. When the first sync byte pattern SB1 is not detected but a second sync byte pattern SB2 is detected, the subsequent second data and error detection correction code are demodulated and the first data is reconstructed by the error detection correction code.

Abstract: This invention relates to a recording medium, data transmission apparatus, data receiver, and optical disk unit, and particularly applies to a system which transmits video data and other data or records them on an optical disk in a predetermined block unit, and permits each frame to be easily and correctly located by low volumes of identification data. At least contiguous synchronization patterns or/and contiguous synchronization patterns with one synchronization pattern interleaved therebetween are assigned with unique combinations.

Abstract: A magnetic disk unit lowers a possibility to cause data reproduction errors by setting a gain of a variable gain amplifier (VGA) at a predetermined fixed level for a predetermined time when an output from the VGA which amplifies an input signal is changed to a value smaller than an optimum value upon occurrence of a thermal asperity and then restoring a variable gain condition so that an output amplitude automatically has a certain preset value.

Abstract: The present invention provides a magnetic disc apparatus comprising: a magnetic disc and a signal processor having functions of (i) setting measurement points at an interval which is smaller in the vicinity of an initial position of a window than in the vicinity of the maximum modification position; (ii) shifting the window from the initial position up to the maximum modification position; (iii) each time the window position is shifted according to the aforementioned interval, reproducing a check data recorded on the magnetic disc, so as to measure an error rate; and (iv) using the error rate measurement results so as to obtain an optimal position of the window.

Abstract: A system, method, and device for sensing temperature during the writing of information onto magnetic media and providing a sufficient write current for that temperature is disclosed. The system comprises a head responsive to a write current for generating a magnetic flux used in writing data onto the magnetic media, a write current source coupled to the head for receiving a write signal and providing write current to the head, and a temperature responsive device coupled to the write current source that senses temperature and provides a write signal whose magnitude is dependent on temperature.

Abstract: A system, method, and device for moving a plurality of heads in a disk drive is disclosed. The system comprises hard disks, read/write heads for reading from or writing to the hard disks, a voice coil motor for moving the plurality of heads, a voice coil motor driver for energizing the voice coil motor, a voltage clamp device for regulating a voltage across the voice coil motor, and a park voltage source. The voltage clamp device comprises a transistor, a switch, and a resistive divider network. During head parking, a park voltage source activates the voltage clamp device, which clamps the voltage across the voice coil motor to a fixed value, resulting in movement of the voice coil and heads towards a park location with fixed velocity.

Abstract: A semiconductor integrated circuit device has a data reproduction circuit for reproducing data read by a head from a magnetic disk during a read operation, a data output circuit for outputting reproduced data obtained as an output of the data reproduction circuit to an external circuit, and an erase current control circuit for controlling an erase current supplied to the head during an erase operation. During an erase operation, the data reproduction circuit is kept deactivated. During transition from an erase operation to a read operation, the data reproduction circuit is activated after the erase current is turned off, and thereafter the data output circuit is activated.

Abstract: A method of controlling a disk drive that reduces the space on the data storage surface of a storage disk otherwise effectively required to be taken up by embedded servo sectors. In disk drives employing wide-writer, narrow-reader, dual element heads, each servo burst field ends with a burst correction value (BCV) field. This BCV field enables the wide-writer head to be accurately positioned within track boundaries before writing begins to the data sector following a servo sector. The present invention takes advantage of the fact that burst correction values are only required by the head incident to data writing operations. Since a finite settle time is required to switch the read channel from servo mode to user data mode, and since the BCV field is not needed for reading operations, mode switching and channel settling can begin while the head is still passing over the BCV field.

Abstract: A magnetic recording control circuit for controlling current through a magnetic recording head includes a switch network, a signal coupler, and first and second voltage clamps. The switch network is connected to first and second magnetic recording head node regions and includes first, second, third, and fourth switches each having a variable magnitude conduction path and a control region. The signal coupler includes an input region and a plurality of output regions each connected to the control region of a corresponding switch. The first and second voltage clamps limit voltage differences between the magnetic recording head node regions and the control regions of the first and second switches.

Abstract: Servo-pattern information is magnetically recorded on a product disc by magnetic print-through from a master medium. The master servo-writing medium is brought into close proximity with the product “slave” disc, and the two are subjected to an external magnetic field which assists in transferring magnetic servo-patterns to the slave disc in a print-through process. The preferred external magnetic field alternates and rotates with respect to the master/slave combination. In an alternative product disc structure, the magnetic layer is magnetically altered in a servo-pattern configuration. Non-magnetic portions of the servo pattern are created which define both gray code and servo burst information for the product disc.

Abstract: A method and apparatus is disclosed that detects servo sectors that contain defects that need to be rewritten and writes in the servo field to correct the detected defects. The system includes a disk for storing data in data regions, the disk further comprising a plurality of servo regions formed radially between the data regions, a motor for rotating the disk, an actuator arm assembly including a head for reading and writing data on the disk and drive electronics for detecting defective servo sectors on the disk and rewriting a servo in the servo sector to correct the detected defective servo sectors.

Abstract: In a data recording apparatus, the period of the first clock signal corresponding to the record data is multiplied by the stated numeric corresponding to the transfer rate with the clock signal forming structure, so that the second clock signal is formed. And, on the basis of the record data and the second clock signal, the recording current corresponding to the transfer rate that is formed by highlighting the high-frequency component in accordance with the transfer rate and by limiting the band in accordance with the transfer rate is generated with the recording current generating structure. Then, the recording data is recorded on the recording medium with the recording structure on the basis of the recording current, therefore, even if the transfer rate varies, it is able to equalize highlighting operation of high-frequency component of the recording current and to equalize band limitation so as to keep the frequency characteristics approximately constant.

Abstract: A method and apparatus for testing digital read channel circuits within a data storage device includes a digital read channel circuit coupled to a simulated impulse response module are disclosed. The data storage device includes a digital read channel circuit coupled to a simulated impulse response module. A pseudo analog-to-digital waveform is generated by the simulated impulse response module is input into the digital read channel circuit. The digital read channel circuit then decodes the pseudo analog-to-digital waveform to form a set of binary data. After receiving the set of binary data, a formatter/deformatter verifies the correctness of the binary data, such that the integrity of the digital read channel circuit and the formatter/deformatter can be determined.