Marvell International Limited

Other

Infineon Technologies Ag

Marvellworld Trade Ltd.

Marvell Asia Pte., Ltd.

Michael Madden

Zining Wu

Gregory Burd

Hongxin Song

Qiyue Zou

Zaihe Yu

Ke Han

Xueshi Yang

Nitin Nangare

Yu-Yao Chang

Pantas Sutardja

Mats Oberg

Hongwei Song

Panu Chaichanavong

Markus Hammes

Heng Tang

Vincent M Wong

Michael Speth

Kar Shing Chiu

Runsheng He

Mark K Goldstein

André Neubauer

Toai Doan

Calvin K Adams

Larry L Hench

Seyed Mehrdad Khatami

Rathnakumar Radhakrishnan

Frank L Bennardo

Jongseung Park

Henry S Pennypacker, Jr

Gerald H Stein

Deborah C Hall

A method of recovering a servo write frequency, to read servo wedge data from a rotating magnetic storage medium having at least one servo wedge that includes a servo preamble written at a known preamble frequency, includes analyzing samples of data read from the rotating magnetic storage medium to identify samples in which energy at the known preamble frequency exceeds a predetermined threshold, declaring the location of the servo preamble based on the identification of the samples in which energy at the known preamble frequency exceeds the predetermined threshold, deriving a phase angle from the samples in which the energy at the known preamble frequency exceeds the predetermined threshold, updating an accumulated phase angle using the derived phase angle, and using the updated accumulated phase angle to start a timing recovery loop to recover the servo write frequency. The analyzing and deriving may be performed using a spectral analysis operation.

Digital timing recovery for servo operations during start-up mode

A method of operating a storage device includes reading data from a storage medium using a detector, processing signals from the detector through a plurality of processing circuits, each respective processing circuit in the plurality of processing circuits being optimized for a different state of a channel condition and providing a respective output metric, selecting a processing circuit from the plurality of processing circuits by comparing the respective output metrics from each processing circuit in a predetermined manner, and designating as output of the detector output of the processing circuit that is selected. The output metrics may be branch metrics or path metrics, and the channel condition may be fly-height or phase shift. The storage device includes a storage medium, and a read channel including a detector, and processing circuits that process signals from the detector. Each respective processing circuit is optimized for a different state of a channel condition.

Method and apparatus for processing multiple servo channels in magnetic recording devices

Embodiments described herein provide methods and systems for correcting a transient phase error induced while recording on a magnetic recording medium. An input signal is received and is distributed to a plurality of sinc filters. A respective phase-shifted signal is generated at each of the plurality of sinc filters by adding a corresponding predetermined amount of phase to the received signals. A respective score is assigned to each of the generated phase-shifted signals. The generated phase-shifted signal having the highest score is selected as the phase-corrected signal to compensate for the transient phase error induced while recording on the magnetic recording medium.

Decision-free timing disturbance cancellation caused by HAMR laser power variation

An improved handrail splice for use in coupling cylindrical handrail components comprises a generally cylindrical splice having a scalloped outer surface defining a plurality of first and second grooves, with the first grooves being characterized as large grooves circumferentially spaced along the outer surface and a plurality of smaller second grooves disposed between the first grooves. The large grooves are sized to receive and maintain a quantity of adhesive therein to ensure a secure adhesive connection between exterior of the tubular splice and the interior handrail surface. The smaller second grooves receive a smaller quantity of adhesive and further function to anchor the splice relative to the hand rail sections by press-fit engagement. A longitudinal slit bounded by a pair of projecting tabs allows for the temporary reduction of the splice to facilitate inserted installation of the splice within a tubular hand rail component.

Splice coupling for connection of tubular handrail sections

A system includes, in at least one aspect, a storage device including patterned media and a head; and a read channel configured to: receive a DC readback signal from the head, the DC readback signal including position error signal (PES) information associated with a position of the head with respect to the patterned media, and determine the position of the head with respect to the patterned media based on a result of summing the DC components of the PES information.

Methods of demodulating a servo position error signal on patterned media

Systems, methods, apparatus, and techniques are provided for producing an estimate of a digital sequence. A continuous-time signal is obtained. The continuous-time signal is sampled with an oversampling factor to produce a discrete-time signal corresponding to the continuous-time signal. A phase offset estimate of the continuous-time signal is produced based on the discrete-time signal. The discrete-time signal is interpolated based on the phase offset estimate to produce an interpolated discrete-time signal. The interpolated discrete-time signal is processed to produce an estimate of a digital sequence.

Repeated runout (RRO) zero phase start (ZPS)

Systems and methods are provided for calibrating signals retrieved from a storage device using a first reader and a second reader. The systems and methods further include reading a first signal using the first reader and a second signal using the second reader. Control circuitry computes a calibration metric associated with the first reader and the second reader based on the combination of the first signal and the second signal. At least one of the first signal and the second signal is subsequently decoded based in part on the computed calibration metric.

Systems and methods for calibrating read and write operations in two dimensional magnetic recording

A read/write channel module for writing data to and reading data from a storage medium. A servo channel module is configured to recover a servo field from the storage medium in accordance with a read signal read from the storage medium and a first clock signal. A locator module is configured to determine, based on a location of the servo field recovered from the storage medium, a location of a predetermined bit pattern that is located subsequent to the servo field on the storage medium. A phase error calculator module is configured to estimate a phase error of a second clock signal based on the location of the predetermined bit pattern, wherein a phase and a frequency of the second clock signal are different than a phase and a frequency of the first clock signal, and adjust the phase of the second clock signal based on the estimated phase error.

Apparatus and method for adjusting a phase of a data clock signal using a predetermined bit pattern

Systems, methods, and other embodiments associated with processing a read signal from a storage medium that includes continuous embedded position information are described. According to one embodiment, an apparatus includes read logic configured to control a storage device to generate the read signal by reading a first layer and a second layer of the storage medium. The first layer defines data and the second layer defines embedded position information. The apparatus includes data detection logic configured to process the read signal to recover the embedded position information. The read logic is configured to control the storage device based, at least in part, on the embedded position information.

Processing a data signal with an embedded position signal

Systems and methods for detecting cycle slip are provided. In some embodiments, a waveform that represents data samples is received. The waveform may include a predetermined preamble and a predetermined postamble. A first value representing a phase of the predetermined preamble of the waveform may be computed. A second value representing a phase of the predetermined postamble of the waveform may be computed. A detection is made as to whether cycle slip occurred during sampling the received waveform based on a comparison of the first value with the second value.

Systems and methods for detecting cycle slip and/or framing error

Apparatus and methods are disclosed for decoding data stored on a data storage medium. A disclosed decoding method and decoder include a radial incoherence (RI) detector that increases the probability of detecting RI and improves the decoding performance in terms of the bit error rate of the decoded signal. RI is detected by comparing an input signal to the decoder against a RI threshold value and generating a RI-type signal. The RI detector may include a filter for filtering out noise and error in the RI-type signal, an adaptive threshold unit that adjusts the RI threshold value based upon the RI-type signal, a transition-based threshold unit that adjusts the RI threshold value based upon each transition in the input signal, or a path-based threshold unit that adjusts the RI threshold value based upon a best surviving path corresponding to the input signal, in combination or alone.

Viterbi decoder method and apparatus with RI detector in servo channel

A system for providing an accumulated phase to an interpolator of a read channel, the interpolator configured to provide a digital clock signal. A frequency accumulator is configured to generate a frequency offset based on a difference between the digital clock signal and a desired clock signal. A zero phase start module is configured to, during a zero phase start, output an incremental phase jump. A phase accumulator is configured to generate the accumulated phase based on the difference between the digital clock signal and the desired clock signal, and, during the zero phase start, the incremental phase jump output by the zero phase start module, or the frequency offset generated by the frequency accumulator or a predetermined frequency offset.

Applying digital frequency offset to timing loop

A read/write channel module including a sampling module configured to sample a read signal corresponding to data stored on a disk. A first preamble is encoded with a first timing recovery pattern on a first track of the disk. The first timing recovery pattern includes a first pattern that changes every x bits. A second preamble is encoded with a second timing recovery pattern on a second track of the disk adjacent to the first track. The second timing recovery pattern includes a second pattern that changes every y bits. A data processing module is configured to process the read signal to remove inter track interference from the read signal based on a difference between the first timing recovery pattern and the second timing recovery pattern.

Systems and methods for performing timing acquisition in a read/write channel module

A system including a first filter module configured to receive an input signal including (i) a first shift in a DC level of the input signal and (ii) a second shift in the DC level of the input signal. The first shift has (i) a first magnitude and (ii) a first duration. The second shift has (i) a second magnitude and (ii) a second duration. The second magnitude is different than the first magnitude. The second duration is greater than the first duration. The first filter module is configured to pass the first shift. The second filter module is configured to detect one or more of (i) the first shift and (ii) the second shift, and in response to detecting one or more of (i) the first shift and (ii) the second shift, filter one or more of (i) the first shift and (ii) the second shift.

Growing community of inventors

Mountain View, CA, United States of America

Michael Madden