G11B5/59622

Data storage device demodulating servo stripes using matched filter

A data storage device is disclosed comprising at least one head configured to access a magnetic tape comprising a plurality of servo frames each comprising a plurality of servo bursts, wherein each servo burst comprises a plurality of servo stripes. The servo stripes in a first servo burst are read using the head to generate a first read signal that is processed using a first matched filter matched to the first servo burst in order to generate an average time stamp for the servo stripes in the first servo burst. A position error signal (PES) is generated based on the average time stamp of the first servo burst, and the head is positioned relative to the magnetic tape based on the PES.

DATA STORAGE DEVICE DEMODULATING SERVO STRIPES USING MATCHED FILTER
20220108721 · 2022-04-07 ·

A data storage device is disclosed comprising at least one head configured to access a magnetic tape comprising a plurality of servo frames each comprising a plurality of servo bursts, wherein each servo burst comprises a plurality of servo stripes. The servo stripes in a first servo burst are read using the head to generate a first read signal that is processed using a first matched filter matched to the first servo burst in order to generate an average time stamp for the servo stripes in the first servo burst. A position error signal (PES) is generated based on the average time stamp of the first servo burst, and the head is positioned relative to the magnetic tape based on the PES.

DATA STORAGE DEVICE DEMODULATING SERVO STRIPES USING MATCHED FILTER
20220108719 · 2022-04-07 ·

A data storage device is disclosed comprising at least one head configured to access a magnetic tape comprising a plurality of servo frames each comprising a plurality of servo bursts. A first servo burst is read using the head to generate a read signal which is sampled to generate signal samples. A first matched filter matched to the first servo burst is used to generate filtered samples in response to the signal samples, and at least part of the filtered samples are interpolated to generate interpolated samples. The interpolated samples are processed to generate a position error signal (PES), and a position of the head relative to the magnetic tape is controlled based on the PES.

SPLIT-ACTUATOR DISK DRIVE THAT USES MICROACTUATOR FEEDFORWARD TO REDUCE EFFECTS OF CROSS-ACTUATOR COUPLING

In a multi-actuator drive, the effect of moving a first actuator (the so-called “aggressor actuator”) in on a second actuator (the so-called “victim actuator”) is reduced or compensated for. A victim feedforward signal is added to a microactuator control signal of the victim actuator in response to a voice-coil motor (VCM) control signal that is applied to the aggressor actuator. The feedforward signal is configured to compensate for disturbances to the victim microactuator caused by VCM commands provided to the aggressor actuator. The feedforward signal is based on a transfer function that models commands added to the victim microactuator, which is coupled to the head of the victim actuator, as a function of the aggressor VCM control signal applied to the aggressor actuator.

MAGNETIC DISK DEVICE AND FILTER COEFFICIENT SETTING METHOD OF THE MAGNETIC DISK DEVICE
20220084552 · 2022-03-17 ·

According to one embodiment, a magnetic disk device includes a controlled object, a controller which controls a motion of the controlled object, and loop shaping filters each connected in parallel to the controller. During a determination of coefficients of the loop shaping filters using a transfer function from outputs of the loop shaping filters to before an input of a disturbance affecting the controlled object, the first set of coefficients of each the loop shaping filter is determined by reflecting a frequency response of the other loop shaping filters, and the determined first sets of coefficients of the loop shaping filters are set to the loop shaping filters, respectively.

DATA STORAGE DEVICE USING WINDOWED DELTA-SIGMA ANALOG-TO-DIGITAL CONVERTER IN DIGITAL CURRENT CONTROL LOOP
20220084548 · 2022-03-17 ·

A data storage device is disclosed comprising a voice coil motor (VCM) configured to actuate a head over a disk. The data storage device further comprises control circuitry comprising a digital current control loop including a windowed delta-sigma analog-to-digital converter (ADC) configured to control the VCM. A vibration of the data storage device is measured, and at least one of a gain or a window of the windowed delta-sigma ADC is configured based on the measured vibration.

Split-actuator disk drive that uses microactuator feedforward to reduce effects of cross-actuator coupling

In a multi-actuator drive, the effect of moving a first actuator (the so-called “aggressor actuator”) in on a second actuator (the so-called “victim actuator”) is reduced or compensated for. A victim feedforward signal for a particular head of the victim actuator is added to a microactuator control signal of the victim actuator in response to a voice-coil motor (VCM) control signal that is applied to the aggressor actuator. The feedforward signal is configured to compensate for disturbances to the victim microactuator caused by VCM commands provided to the aggressor actuator. The feedforward signal is based on a transfer function that models commands added to the victim microactuator, which is coupled to the particular head of the victim actuator, as a function of the aggressor VCM control signal applied to the aggressor actuator.

SPLIT-ACTUATOR DISK DRIVE THAT USES MICROACTUATOR FEEDFORWARD TO REDUCE EFFECTS OF CROSS-ACTUATOR COUPLING

In a multi-actuator drive, the effect of moving a first actuator (the so-called “aggressor actuator”) in on a second actuator (the so-called “victim actuator”) is reduced or compensated for. A victim feedforward signal for a particular head of the victim actuator is added to a microactuator control signal of the victim actuator in response to a voice-coil motor (VCM) control signal that is applied to the aggressor actuator. The feedforward signal is configured to compensate for disturbances to the victim microactuator caused by VCM commands provided to the aggressor actuator. The feedforward signal is based on a transfer function that models commands added to the victim microactuator, which is coupled to the particular head of the victim actuator, as a function of the aggressor VCM control signal applied to the aggressor actuator.

Data storage device compensating for seek vibration using vibration sensor

A data storage device is disclosed comprising an actuator configured to actuate a head over a disk surface, and a vibration sensor configured to generate a vibration signal (VS). Control circuitry comprising a servo control system having a torque rejection curve (TRC) configured to control the actuator is configured to measure a position error signal (PES) of the head, and measure the VS output by the vibration sensor. A feed-forward compensator is configured based on PES/VS/TRC. While seeking the head across the disk surface, the VS is processed using the feed-forward compensator to generate a feed-forward compensation during a settle interval of the seek, and the actuator is controlled using the feed-forward compensation during the settle interval.

Two dimensional magnetic recording (TDMR) off-track performance improvement
10916270 · 2021-02-09 · ·

In a two-dimensional magnetic recording (TDMR) system, a first finite impulse response (FIR) filter processes data read from a track of a magnetic medium by a first head using first filter tap values determined a priori independently of a second head. A second FIR filter processes data read from a track by the second head using second filter tap values determined a priori independently of the first head. A read channel module generates an output based on outputs of the first and second FIR filters.