298results about "Carrier speed control/regulation/indication" patented technology

A disk drive is disclosed comprising an interface for receiving a primary supply voltage and a secondary supply voltage from a host computer. The primary supply voltage is applied to the windings of a multi-phase spindle motor in a commutation sequence, and the secondary supply voltage is connectable to a center tap of the windings.

A disk drive is disclosed employing either back electromotive force (BEMF) spindle speed control mode or wedge spindle speed control mode. A BEMF detector monitors the BEMF voltage generated by the windings of the spindle motor to generate a BEMF speed error. The BEMF spindle speed control mode is used to spin up the disk to an operating speed, and the wedge spindle speed control to maintain the disk at the operating speed. While in the wedge spindle speed control mode, a BEMF detection window is disabled to reduce acoustic noise.

A disk drive is disclosed comprising a disk, a head actuated over the disk, and a spindle motor for rotating the disk, the spindle motor comprising a plurality of windings. Disk control circuitry executes a spin-down operation of the spindle motor by estimating an angular position of the spindle motor by applying a voltage to at least one of the windings and evaluating a rise time of current flowing through the winding. The windings are commutated in response to the estimated angular position, and a driving current is applied to the windings to brake the spindle motor.

A disk drive is disclosed comprising a spindle motor having a plurality of windings including at least a first winding, a second winding, and a third winding. During a spin-up operation, a voltage is applied to the first winding and a first rise time is measured for current flowing through the first winding to reach a predetermined threshold. A voltage is applied to the second winding and a second rise time is measured for current flowing through the second winding to reach a predetermined threshold. A voltage is applied to the third winding and a third rise time is measured for current flowing through the third winding to reach a predetermined threshold. A difference is computed in response to the first rise time, the second rise time, and the third rise time, and an angular position of the spindle motor is estimated by computing an arctangent in response to the difference.

A disk drive is disclosed comprising an interface for receiving a supply voltage from a host computer and control circuitry for controlling at least one operation of the disk drive. The supply voltage is applied to the windings of a multi-phase spindle motor in a commutation sequence during a normal operating mode, and a secondary voltage supplied by a center tap of the windings is used to power the control circuitry during the normal operating mode.

The magnetic tape device includes: a magnetic tape; and a reproducing head, in which a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m/sec, the reproducing head is a magnetic head including a tunnel magnetoresistance effect type element as a reproducing element, the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide, and a C—H derived C concentration calculated from a C—H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %.

A tape transport servo system and method that do not make use of tachometers and/or encoders to derive tape velocity and position are provided. The tape transport servo system and method derive velocity and position of the tape from a primary and direct manner and also a secondary or alternative manner, especially when the primary or direct manner cannot be used. The tape transport servo system and method control a tape drive and moves a tape between one reel driven by one motor to another reel driven by another motor. The tape is read by a recording head composed of data readers, data writers and a dedicated set of servo read elements. A position and a velocity of the tape are determined from a primary velocity source when the tape is being read by the head. The position and the velocity of the tape are determined from a secondary velocity source when the tape is not being read by the head. The velocity of the tape is compared to a desired programmed reference velocity for the tape. The velocity of the tape is driven to the desired programmed reference velocity if the velocity is not equal to the desired velocity. The velocity of the tape is controlled by regulating the velocity and the driving currents of the motors. The tape transport servo system comprises a digital signal processor and a servo motor control system. The servo motor control system comprises a servo logic system, sensors, PWM motor drivers, power amplifiers, DACs, counters, computation systems, and a timing-based servo pattern monitoring system.

A system provided for protecting a disk drive from impact damages. More specifically, a disk drive is provided that includes an accelerometer interconnected to a printed circuit board that detects free fall of the disk drive. In addition, the velocity of spinning disks of the disk drive is also monitored to assess changes in velocity thereof that may indicate the presence of a tumbling condition. Furthermore, the change in acceleration measured by the accelerometer is monitored to prevent false indications of free fall due to common vibrations. Thus an enhanced system is provided that protects disk drives from the effect of free falls under a wide variety of conditions and allowing for drops from shorter distances to be identified.

In cold weather, the higher torque required for normal spinning operation of a spindle motor assembly in a direct access storage device due to the increased viscosity of the grease, is overcome by localizing the heating to the spindle motor assembly to reduce the viscosity of the grease, and then let a disk driven self heat during and after spin-up of the spindle motor assembly.

Servo control methods and apparatus for a tape drive. A read/write head reads and writes data on magnetic tape with at least one servo track providing transverse position information. At least two servo readers arranged for reading a servo track associated with the read/write head operate concurrently to generate servo read signals. A position estimator processes each servo read signal to generate a series of position values corresponding to respective time instants indicative of their transverse positions. A servo controller calculates a skew value indicative of tape skew relative to the read/write head and a tension variation value indicative of variation of tape tension. The servo controller is adapted to account for cross-coupling between tape skew and tension variation.

Attributes of a hard disk drive are stepped between different power consumption levels to optimize the trade-off between minimizing power consumption and maximizing performance depending on whether AC or battery power is used. One attribute is the clock speed which can be changed for a number of disk drive components including the processor, the external interface bus and the memory interface bus. The system power supply voltage can further be changed in a number of components integrated together on an application specific integrated circuit (ASIC). Further, spindle motor rotation speed can be changed, or the spindle motor spun-down. Further, actuator movement by the VCM can be controlled to provide faster movement during track seek operations when high performance is desired. Additionally, write-back caching parameters are adjusted based on the source of power for the hard drive, be it battery, AC power, or a combination.

A magnetic tape apparatus includes a magnetic tape, a reading element unit and an extraction unit, in which the magnetic tape includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support, a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the magnetic layer is equal to or smaller than 0.050, and an extraction unit performs a waveform equalization process according to a deviation amount between positions of the magnetic tape and the reading element unit, with respect to each reading result for each reading element, to extract data derived from the reading target track from the reading result.

A magnetic tape apparatus, in which an intensity ratio of peak intensity of diffraction peak of (110) plane with respect to peak intensity of diffraction peak of (114) plane of a hexagonal ferrite crystal structure obtained by XRD analysis of the magnetic layer by In-Plane method is 0.5 to 4.0, a vertical squareness ratio of the magnetic tape is 0.65 to 1.00, a reading element unit includes a plurality of reading elements each of which reads data by a linear scanning method from a specific track region including a reading target track in a track region included in the magnetic tape, and an extraction unit performs a waveform equalization process according to a deviation amount between positions of the magnetic tape and the reading element unit, with respect to each reading result for each reading element, to extract data derived from the reading target track from the reading result.

A disk drive configured to control spindle spin is provided. The disk drive includes a spindle motor for spinning a disk configured for storing data, a nonvolatile memory comprising instructions associated with a first process for spin-up of the spindle motor from a power-on mode and the nonvolatile memory comprising instructions associated with a second process for spin-up of the spindle motor from a power save mode, a controller for determining which of the first or the second process for spin-up of the spindle motor to implement in accordance with the instructions stored in the nonvolatile memory and a motor driver for spinning up the spindle motor according to the first process or according to the second process for spin-up of the spindle motor.

A rotational operation mechanism for a DJ apparatus enables smooth rotation to be achieved using a simple configuration. A rotational operation mechanism has a base, a display window member fixed onto the base, a ring member positioned on the display window member and holding a plurality of rotatable balls, and a rotation operation portion positioned on the ring member and operated by an operator. Mutually facing surfaces of the display window member and the rotation operation portion are provided with grooves that have substantially the same diameter as the ring member. The ring member is sandwiched between the display window member and the rotation operation portion such that the plurality of balls are received in the groove of the display window member and the groove of the rotation operation portion, and the ring member is rotatable in a peripheral direction. One of the rotation operation portion and the base is provided with magnets and the other of the rotation operation portion, and the base is provided with metal portions at positions facing the magnets.

A disk drive having a motor and a velocity control loop, which includes a frequency detector and a filter. The filter includes a filter section and an accumulator. The filter is programmable in that filter coefficient(s) are dynamically received by the filter section. One embodiment of the filter section is an infinite impulse response filter. One embodiment of the filter is a digital integrated circuit. A method for compensating a control loop by infinite impulse response filtering and accumulating. The control loop may be a position, velocity, acceleration or force control loop. A programmable digital integrated circuit for compensating a velocity control loop having a filter section cascaded with an accumulator. The integrated circuit may include memory for storing filter coefficient(s) for the filter section, thereby not requiring external components.