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539results about "Analogue recording" patented technology

Active fly height control crown actuator

A micro-actuator is comprised of a piezoelectric motor mounted on a flexure tongue with offsetting hinges, to perform a fine positioning of the magnetic read / write head. The substantial gain in the frequency response greatly improves the performance and accuracy of the track-follow control for fine positioning. The simplicity of the enhanced micro-actuator design results in a manufacturing efficiency that enables a high-volume, low-cost production. The micro-actuator is interposed between a flexure tongue and a slider to perform an active control of the fly height of the magnetic read / write head. The induced slider crown and camber are used to compensate for thermal expansion of the magnetic read / write head, which causes the slider to be displaced at an unintended fly height position relative to the surface of the magnetic recording disk. The enhanced micro-actuator design results in reduced altitude sensitivity, ABS tolerances, and reduced stiction. The controlled fly height of the magnetic read / write head prevents a possibility of a head crash, while improving the performance and data integrity.
Owner:WESTERN DIGITAL TECH INC

Disk drive employing a disk with a pristine area for storing encrypted data accessible only by trusted devices or clients to facilitate secure network communications

A disk drive is disclosed comprising a disk for storing data, the disk comprising a public area for storing plaintext data and a pristine area for storing encrypted data. The disk drive comprises a head for reading the encrypted data from the pristine area of the disk, and a control system for controlling access to the pristine area of the disk. Authentication circuitry within the disk drive is provided for authenticating a request received from an external entity to access the pristine area of the disk and for enabling the control system if the request is authenticated. The disk drive further comprises a secret drive key, and decryption circuitry responsive to the secret drive key, for decrypting the encrypted data stored in the pristine area of the disk.
Owner:WESTERN DIGITAL VENTURES

Setting an operating bias current for a magnetoresistive head by computing a target operating voltage

A disk drive is disclosed having a disk, and a head actuated over the disk, the head comprising a magnetoresistive (MR) element. Control circuitry within the disk drive sets an operating bias current for the MR element by computing a target voltage for the MR element, applying a bias current to the MR element, measuring a voltage across the MR element corresponding to the bias current, and adjusting the bias current applied to the MR element until the measured voltage substantially equals the target voltage.
Owner:WESTERN DIGITAL TECH INC +1

Demagnetizing a head in a disk drive by increasing the frequency of an AC write signal while maintaining the write current amplitude

A disk drive is disclosed which demagnetizes the head after a write operation. Write circuitry applies a write signal to the head in order to write data to a selected data sector during a write operation, wherein the write signal comprises a predetermined write current amplitude. Control circuitry demagnetizes the head at the end of the write operation by maintaining the write current amplitude while increasing a frequency of an AC write signal applied to the head over a predetermined demagnetization interval, wherein increasing the frequency of the AC write signal decreases an amplitude of the AC write signal when observed at the head.
Owner:WESTERN DIGITAL TECH INC

Disk drive adjusting head bias during servo synchronization to compensate for over/under sensitivity

A disk drive is disclosed comprising a disk including a plurality of servo sectors, a head actuated over the disk, the head for generating a read signal, and a gain control circuit for adjusting a gain of the read signal in response to a gain setting. A bias setting is initialized for the head, and the gain setting for the read signal is initialized. The read signal is processed to detect at least one of the servo sectors, and when at least one of the servo sectors is not detected, the gain setting is adjusted. The read signal is processed with the adjusted gain setting to detect at least one of the servo sectors, and when at least one of the servo sectors is not detected with the adjusted gain setting, the bias setting is adjusted in response to the adjusted gain setting.
Owner:WESTERN DIGITAL TECH INC

Magnetic tape and maufacturing method thereof, and servo writer and servo write method

A magnetic tape of the present invention comprises a plurality of servo bands and servo signals for performing tracking-control of a magnetic head, wherein the servo signals are recorded on the servo bands, wherein a DC magnetization region magnetized in one direction by direct current is arranged along longitudinal directions of the magnetic tape on the servo bands, wherein each of the servo signals is magnetized in a reverse direction for the one direction of a DC magnetization and is recorded within the DC magnetization region, and wherein any of a relative ratio and relative difference of DC magnetization intensity in the DC magnetization region and recording magnetization intensity of each of the servo signals differs for each of the servo bands.
Owner:FUJIFILM HLDG CORP +1

Inductive power supply

In one aspect, the present invention provides a wireless power supply having a plunger for mechanically interconnecting a remote device with the power supply. The plunger may be extendable / retractable to interfit with the remote device. In a second aspect, the present invention provides a wireless power supply with a movable primary that allows for close alignment between the primary and the secondary when the remote device is disposed within a range of different positions with respect to the charging surface. The movable primary may, for example, be coupled to the remote device by a peg, a plunger or a magnet. Alternatively, the position of the movable primary may be adjusted manually. In a third aspect, the present invention provides a charging bowl having a plurality of charging stations disposed about a common axis. Each charging station may include a movable primary that permits some freedom in positioning of the remote device on the charging surface. In a fourth aspect, the present invention provides a wireless power supply having a manually movable primary.
Owner:PHILIPS IP VENTURES BV

Multi-level recording on shingled coherent magnetic media

A data storage system includes recording media with a shingled track pattern of multiple data tracks in which mapped data bits are recorded. The mapped data are coherently aligned with one another across the multiple data tracks. A read head has an effective read head width that extends across the multiple data tracks and that is aligned to coherently read the mapped data bits. A read head output includes a non-binary multi-level amplitude summation of the mapped data bits.
Owner:SEAGATE TECH LLC

Adaptive equalizer

An adaptive equalizer comprising a variable filter which equalizes a digital input signal which is input in a time sequential order, an adaptive controller unit which updates a filter coefficient of the variable filter based on an output signal of the variable filter and the input signal and according to an equalization algorithm, and a coefficient resetting unit which resets a filter coefficient of the variable filter at a predetermined timing.
Owner:SEMICON COMPONENTS IND LLC

Assembly for thermal and/or thermally-assisted information processing

An information processing assembly includes at least one heater suitable for information processing, and a controller for controlling the at least one heater by at least one of adjusting a power to the at least one heater to match a target power level, and changing a polarity of an electrical current supplied to the heater.
Owner:WESTERN DIGITAL TECH INC

Method for magnetic recording on patterned multilevel perpendicular media using variable write current

A magnetic recording method uses a patterned perpendicular magnetic recording medium where each magnetic block or island contains a stack of individual magnetic cells to providing multilevel recording. Each cell in an island is formed of a material or set of materials to provide the cell with perpendicular magnetic anisotropy and is a single magnetic domain. Each cell is magnetically decoupled from the other cells in its island by nonmagnetic spacer layers. Thus each cell can have a magnetization (magnetic moment) in one of two directions (into or out of the plane of the layer making up the cell), and this magnetization is independent of the magnetization of the other cells in its island. This permits multiple magnetic levels or states to be recorded in each magnetic island.
Owner:WESTERN DIGITAL TECH INC

Magnetic data system having bias circuit with bias resistor

A magnetic data system according to one embodiment includes at least one reader formed above a substrate, the at least one reader further comprising a shield and a magnetoresistive (MR) sensor. A first circuit sets a voltage (Vsub) of the substrate to about a voltage (Vshield) of the shield of the at least one reader.
Owner:INT BUSINESS MASCH CORP

Audiovisual (AV) device and control method thereof

According to one embodiment, video image and audio signals are transmitted to a plurality of electronic devices each having at least one of a video image display function and an audio reproducing function. Information indicating the fact that at least one of a video image and audio has been set in a mute state is acquired from each of the electronic devices. Based on the information, a processing operation is applied to the video image and audio signals supplied to each of the electronic devices.
Owner:KK TOSHIBA

Method and apparatus for cache management for a digital VCR archive

An apparatus marks files within a content archive. The content archive contains a database that has a plurality of content files. The content archive also contains a plurality of entries or records. Each of the entries corresponds to a distinct one of the plurality of content files. Each of the entries also includes a played field that is automatically set when the corresponding content file has been played. The content archive also includes a writing module that is configured to record a new content file to the content archive and, if insufficient space is available, to overwrite a content file for which the played fields are set. According to one aspect, the plurality of entries also includes an entry corresponding to an overwritten content file previously contained within the database that is no longer contained within the database. The database may contain references to content no longer in the database.
Owner:ATI TECH INC

Method for actively controlling electric potential at the head/disk interface of a magnetic recording disk drive

An electrical potential difference between a slider body and a hard disk of a hard disk drive is eliminated based on the flying-height spacing of the slider body between the slider body and the hard disk. A predetermined bias voltage is applied between the slider body and the hard disk that includes a DC component and an AC component and that is based on the detected flying-height spacing of the slider body. The flying-height spacing can be detected based a minimum slider-to-disk clearance change from a design flying height of the slider at a frequency of the AC component as the DC component of the predetermined bias voltage is varied. Alternatively, the flying-height spacing can be detected based on a minimum electrodynamic response of the slider to a first harmonic of the AC frequency of the AC component as the DC component is varied.
Owner:WESTERN DIGITAL TECH INC

Shingled magnetic recording disk drive with minimization of the effect of far track erasure on adjacent data bands

A shingled magnetic recording (SMR) hard disk drive (HDD) essentially eliminates the effect of far track erasure (FTE) in the boundary regions of annular data bands caused by writing in the boundary regions of adjacent annular data bands. The extent of the FTE effect is determined for each track within a range of tracks of the track being written. Based on the relative FTE effect for all the tracks in the range, a count increment (CI) table or a cumulative count increment (CCI) table is maintained for all the tracks in the range. For every writing to a track in a boundary region, a count for each track in an adjacent boundary region, or a cumulative count for the adjacent boundary region, is increased. When the count reaches a predetermined threshold the data is read from that band and rewritten to the same band.
Owner:WESTERN DIGITAL TECH INC

Recording method for magnetic recording medium, recording device for magnetic recording medium and magnetic recording medium

After a DC erasing is performed in a direction by permanent magnets on a servo signal recording part, servo signals are recorded in the signal recording area of the servo signal recording part by a magnetic field in the direction opposite to that of the DC erasing. Thus, in a recording method for a magnetic recording medium having a data signal recording part and the servo signal recording part on a magnetic layer, accurate servo signals can be recorded and reproduced even on the medium having the magnetic layer of 0.13 μm or smaller.
Owner:SONY CORP

Playback apparatus and method

A playback apparatus used for an audio database includes a first acquisition unit configured to acquire first position information and second position information, an estimation unit configured to estimate a required period from a first position to a second position based on the first position information and the second position information, a second acquisition unit configured to acquire a data length of an audio signal to be played back from the audio database, a determination unit configured to determine a playback speed required to play back the audio signal based on the required period and the data length to complete playback of the audio signal within the required period, and a playback unit configured to play back the audio signal according to the playback speed.
Owner:KK TOSHIBA

Method and apparatus for write head demagnetization

An apparatus and method for demagnetizing a write head of a disc drive. Under control of a clock oscillator, synthetic demagnetizing pulses are generated and applied to a writer-driver bridge. Also under control of the clock oscillator, a write current produced by the writer-driver bridge incorporates the demagnetizing pulses and ramps down to about zero. The train of demagnetizing pulses and the write current ramp down demagnetizes the head, reducing write head magnetic bias that may influence the proximate read head of the disc drive head.
Owner:AVAGO TECH INT SALES PTE LTD
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