International Business Machines Corporation

Other

Flir Systems, Incorporated

Robert Allen Hutchins

Sedat Oelcer

Evangelos Stavros Eleftheriou

Jens Jelitto

Glen Alan Jaquette

Giovanni Cherubini

Nhan Xuan Bui

Kazuhiro Tsuruta

Larry LeeRoy Tretter

Ernest Stewart Gale

Jacob Lee Dahle

Eric Rolf Christensen

Alan Robert Clark

Roy Daron Cideciyan

Eiji Ogura

James Mitchell Karp

Alex Chliwnyj

Mark Allan Taylor

Ara Sarkis Patapoutian

Alan D Kathman

Reed Alan Hancock

David Berman

Constantin Michael Melas

Sushama M Paranjape

Gene H Sonu

Melanie Jean Sandberg

Justin Ryan Cripps

Pantas Sutardja

Mark Alfred Lantz

Thomas R Albrecht

Thomas Mittelholzer

Allen Keith Bates

James Howard Eaton

Steven Ross Bentley

David Michael Davis

Robert Carl Barrett

Hisato Matsuo

Scott Jeffrey Schaffer

Steven Carter Wills

John James Gniewek

Shuhei Nadehara

Demura Masayuki

Evangelos S Eleftherion

A planar line generator including a first planar surface extending in a first direction, a second planar surface facing the first planar surface, and a beam splitter in front of the second planar surface, the beam splitter configured to output, from light incident thereon, an undeflected beam, a first beam deflected to a first side of the undeflected beam along the first direction, and a second beam deflected to a second side of the undeflected beam along the first direction, wherein the second planar surface includes a line diffuser configured to receive the undeflected beam, and first and second diffusers having a design different from the line diffuser, the first and second diffusers being configured to receive the first and second beams, respectively.

Planar high angle line generator

A method according to one embodiment includes receiving an increment signal at a first integrator when a second integrator overflows; receiving a decrement signal at the first integrator when the second integrator underflows; and incrementing or decrementing a gain applied to an analog signal based on receipt of the increment or decrement signal. A system according to one embodiment includes a first integrator configured to cause incrementing of a gain applied to an analog signal based on receipt of an increment signal when a second integrator overflows, the first integrator being configured to cause decrementing of the gain applied to the analog signal based on receipt of a decrement signal when the second integrator underflows; and the second integrator.

Gain control with multiple integrators

A method for selecting which tap coefficients of a programmable finite-impulse-response (FIR) equalizer to fix is disclosed. In one embodiment, such a method includes performing an initial calibration to determine an initial value for each tap coefficient of a FIR equalizer. These initial values may be used to produce a first waveform. The method then performs an operation on the first waveform to produce a second waveform comprising multiple lobes. The second waveform is then analyzed to determine one or more lobes of the second waveform that have the largest area. The method then fixes coefficients of one or more taps that are closest to the lobe or lobes having the largest area. A corresponding apparatus and computer program product are also disclosed.

Fixing tap coefficients in a programmable finite-impulse-response equalizer

A method for selecting which tap coefficients of a programmable finite-impulse-response (FIR) equalizer to fix includes performing an initial calibration to determine an initial value for each tap coefficient of a FIR equalizer. Using these initial values, a 'total' FIR equalizer is determined which sets the tap coefficients to their initial values. The method further determines multiple sets of tap coefficients that may potentially be fixed in the FIR equalizer. For each set of tap coefficients that may potentially be fixed, the method determines a 'fixed' FIR equalizer that sets the tap coefficients in the set to their initial values and other tap coefficients to zero. The method then determines a phase-difference energy between the &#x201c;total&#x201d; FIR equalizer and the &#x201c;fixed&#x201d; FIR equalizer for each set of tap coefficients that may potentially be fixed. The set of tap coefficients associated with the lowest phase-difference energy are then fixed.

Technique for fixing tap coefficients in a programmable finite-impulse-response equalizer

A fanout diffractive optical element having a discrete periodic surface relief structure having a 2-dimensional (x,y) shape is described. The surface relief structure can include a first lobe and a second lobe separated by a waist region having a width less than the first lobe and the second lobe. The 2-dimensional (x,y) shape of surface relief structure can have an inversion center and can lack symmetry about any plane that is normal to the surface relief structure. Also described are apparatuses having a fanout diffractive optical element and methods of producing a plurality of light diffracting orders using a fanout diffractive optical element.

Diffractive optical elements and applications thereof

Provided are a method, servo channel, and tape drive for determining a reference waveform used by a correlator in a servo channel. Sequences of servo signal samples are provided from read servo signals read from a servo pattern on a recording medium. A determination is made of a reference waveform based on the sequences of servo signal samples and the reference waveform is forwarded. Interpolated servo signals are generated. The interpolated servo signal samples and the forwarded reference waveform are received to generate correlation output samples. Position and velocity information are calculated from the correlation output samples.

Determining a reference waveform used by a correlator in a servo channel

A method for monitoring a plurality of servo channels, providing a finite state machine ('FSM') comprising a single servo channel mode and a combined servo channel mode, and moving a sequential information storage medium comprising a plurality of servo bands across a read/write head comprising a corresponding plurality of servo sensors. The method further asserts an acquisition flag by a servo channel if that servo channel is tracking a servo pattern, and asserts a bit flag by a servo channel if a new LPOS bit is decoded. If at least one acquisition flag is asserted, the method determines if a bit flag is asserted by a servo channel associated with said asserted acquisition flag, and if an acquisition flag and a bit flag are asserted by a servo channel, the method determines a relative positioning of each servo sensor with respect to an associated servo pattern.

Control method and apparatus for a dual-channel weighted LPOS combining scheme

A system according to one embodiment includes an analog input for receiving an analog signal; a variable gain amplifier coupled to the analog input; a first gain control circuit coupled to the variable gain amplifier for controlling the gain of the analog signal; an analog to digital converter for converting the analog signal to a digital signal; a first gain error generation circuit for generating a first gain error signal based on an output of the analog to digital converter, the first gain error signal or derivative thereof being received by the first gain control circuit; and a second gain error generation circuit for generating a second gain error signal based on the digital signal, the second gain error signal or derivative thereof being received by the first gain control circuit, wherein the first gain control circuit uses at least one of the gain error signals to control the gain of the analog signal.

Dual gain control for magnetic data storage system

A method to position a head module, where the head module comprises at least one servo element and a plurality of data elements, where the servo element and each of the plurality of data elements can detect a servo signal, wherein the method includes moving a sequential information storage medium having a servo band encoded therein across the head module and detecting the servo band using the at least one servo element or any one of the plurality of data elements.

Method and apparatus to position a head module comprising servo elements and a plurality of data elements

A sequential information storage medium, comprising a plurality of servo patterns encoded lengthwise thereon, wherein each servo pattern encodes at least one LPOS bit and comprises a width less than 187 microns.

Apparatus and method to transfer data to and from a sequential information storage medium

A system according to one embodiment includes an analog input for receiving an analog signal; a variable gain amplifier coupled to the analog input; a first integrator coupled to the variable gain amplifier for controlling the gain of the analog signal; a second integrator generating control signals for controlling functions of the first integrator; a serializer for serializing the control signals; and a deserializer coupled to the serializer for deserializing the control signals and passing the deserialized control signals to the first integrator.

A system in one embodiment includes multiple analog inputs for receiving readback signals, an analog to digital converter coupled to each of the analog inputs for converting the readback signals to digital signals, a buffer coupled to outputs of the analog to digital converters for at least temporarily storing the digital signals, and a digital processing section also coupled to outputs of the analog to digital converters for processing the digital signals for reconstructing data therefrom. A method in one embodiment includes receiving multiple channels of analog readback signals from a magnetic head, converting the analog signals in each channel to digital signals, buffering the digital signals, and outputting the buffered digital signals. A method in another embodiment includes receiving a readback waveform from a magnetic storage device, reducing a frequency offset of the readback waveform, and generating a synchronized, oversampled waveform from the readback waveform.

System, method, and computer program product for characterizing media associated with data storage channels

Timing based servo bursts of servo frames, in which the frames are arranged to be symmetric with the same number of servo stripes in each burst of a frame, are synchronized by shifting selected bits. For example, servo frames are arranged with four servo bursts with an equal number of servo stripes in each burst, the servo frames comprising two symmetric sub-frames, each sub-frame comprising two bursts of servo stripes that are parallel to each other within a burst, and the bursts are non-parallel with respect to each other; each servo burst is arranged to comprise at least one reference servo stripe; and each servo burst is arranged to comprise at least one shifted servo stripe, wherein the shift is in the same longitudinal direction with respect to at least one reference servo stripe for each burst of a frame and the opposite longitudinal direction for bursts of sequentially adjacent frames.

Synchronization of symmetric timing based servo bursts

Common sample timing control for sample timing of multiple read channels, wherein the signal clocking of the signals received by the multiple read channels are correlated, for example from parallel tracks of magnetic tape that have been written simultaneously. In one embodiment, a common sample timing control comprises multiple phase error inputs, each indicating phase error of one of the read channels. Logic responsive to the multiple phase error inputs is configured to weight and crosscouple the phase error indication of each phase error input with the phase error indication of each other phase error input, and to apply gain related to the variance of noise of the phase error indications. Feedback logic is responsive to the crosscoupling and is configured to provide a sample timing phase estimate for each read channel.

Common state-space multi-channel digital sample timing phase control of multiple read channels for correlated signals

Growing community of inventors

Tucson, AR, United States of America

Robert Allen Hutchins