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公开(公告)号：US07000167B2
公开(公告)日：2006-02-14
申请号：US10044624
申请日：2002-01-08
申请人： Jon Coker , Ajay Dholakia , Evangelos S. Eleftheriou , Rick Galbraith , Thomas Mittelholzer , Sedat Oelcer
发明人： Jon Coker , Ajay Dholakia , Evangelos S. Eleftheriou , Rick Galbraith , Thomas Mittelholzer , Sedat Oelcer
IPC分类号： H03M13/00
CPC分类号： H03M13/112 , H03M13/1117 , H03M13/1515 , H03M13/255 , H03M13/2906 , H03M13/6331 , H03M13/6583
摘要： A method for decoding Low Density Parity Check (LDPC) codes comprises executing a sum product algorithm to recover a set of information bits from an LDPC code represented as a bipartite graph of symbol nodes and check nodes, the sum product algorithm being responsive to input log likelihood ratios associated with the symbol nodes. The check nodes are updated by generating a set of forward difference metrics and a set of backward difference metrics in dependence on the ratios of logarithmic probabilities each associated with a corresponding symbol node of the LDPC code, updating each metric in the set of forward difference metrics in dependence on the absolute value of the log likelihood ratio associated with the symbol node and the absolute value of the previous metric in the set, updating each metric in the set of backward difference metrics in dependence on the absolute value of the log likelihood ratio associated with the symbol node and the absolute value of the previous metric in the set, and generating log likelihood ratios to be propagated back to each symbol node in dependence on the updated sets of forward and backward difference metrics.
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公开(公告)号：US08443273B2
公开(公告)日：2013-05-14
申请号：US12750350
申请日：2010-03-30
IPC分类号： G06F11/00
CPC分类号： G11B20/10009 , G11B20/10046 , G11B20/10379 , G11B20/10509 , G11B2220/2516
摘要： According to one embodiment, a data detection system includes a coefficient-and-variance engine for selecting which infinite impulse response (IIR) filter and prediction error variance to process and store at any time, and a maximum-likelihood sequence detector. The coefficient-and-variance engine comprises a filter bank storing a plurality of IIR filters that represent a plurality of data-dependent noise whitening or noise prediction filters; a least-mean square (LMS) engine for adapting each IIR filter to actual noise conditions: a variance hank storing a plurality of prediction error variance values; and a data-dependent prediction error variance computation unit which updates the plurality of prediction error variance values. The maximum-likelihood sequence detector includes a metric computation unit that employs the plurality of IIR filters in the filter bank and the plurality of prediction error variances in the variance bank to adaptively compute detector branch metrics. Other systems and methods are also described in other embodiments.
摘要翻译： 根据一个实施例，数据检测系统包括用于选择在任何时间处理和存储的无限脉冲响应（IIR）滤波器和预测误差方差的系数和方差引擎和最大似然序列检测器。 系数和方差引擎包括存储多个表示多个数据相关噪声白化或噪声预测滤波器的IIR滤波器的滤波器组; 用于使每个IIR滤波器适应于实际噪声条件的最小均方（LMS）引擎：存储多个预测误差方差值的方差汉克; 以及数据相关预测误差方差计算单元，其更新所述多个预测误差方差值。 最大似然序列检测器包括在滤波器组中采用多个IIR滤波器的度量计算单元，并且方差库中的多个预测误差方差自适应地计算检测器分支度量。 其他系统和方法也在其他实施例中描述。
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3.发明授权Equalizer computation in a media system using a data set separator sequence 有权使用数据集分隔符序列的媒体系统中的均衡器计算公开(公告)号：US08194342B2
公开(公告)日：2012-06-05
申请号：US13096811
申请日：2011-04-28
IPC分类号： G11B5/035
CPC分类号： G11B5/09 , G11B20/10009 , G11B20/10046 , G11B20/10481 , G11B2005/0013 , G11B2220/90
摘要： An equalizer coefficients generator receives a DSS sequence and a DSS readback sequence, which is a function of a channel processing of the DSS sequence by a read channel. The generator generates a coefficient cyclic equalizer vector as a function of the DSS sequence and the DSS readback sequence. The generator further generates an error signal as a function of a comparison of the DSS sequence and an equalization of the DSS readback sequence based on the coefficient cyclic equalizer vector. An unacceptable error signal indicates a need to adjust the coefficient cyclic equalizer vector to yield an acceptable comparison of the DSS sequence and an equalization of the DSS readback sequence based on the coefficient cyclic equalizer vector.
摘要翻译： 均衡器系数发生器接收DSS序列和DSS回读序列，DSS序列是通过读通道的DSS序列的信道处理的函数。 发生器产生作为DSS序列和DSS回读序列的函数的系数循环均衡器向量。 发生器还根据系数循环均衡器矢量，作为DSS序列与DSS回读序列的均衡的比较的函数产生误差信号。 不可接受的误差信号指示需要调整系数循环均衡器向量以产生DSS序列的可接受比较和基于系数循环均衡器向量的DSS回读序列的均衡。
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4.发明申请METHOD FOR AN EQUALIZER COMPUTATION IN A MEDIA SYSTEM USING A DATA SET SEPARATOR SEQUENCE 有权使用数据集分离器序列在媒体系统中均衡器计算的方法公开(公告)号：US20110200090A1
公开(公告)日：2011-08-18
申请号：US13096811
申请日：2011-04-28
IPC分类号： H03K5/159
CPC分类号： G11B5/09 , G11B20/10009 , G11B20/10046 , G11B20/10481 , G11B2005/0013 , G11B2220/90
摘要： An equalizer coefficients generator receives a DSS sequence and a DSS readback sequence, which is a function of a channel processing of the DSS sequence by a read channel. The generator generates a coefficient cyclic equalizer vector as a function of the DSS sequence and the DSS readback sequence. The generator further generates an error signal as a function of a comparison of the DSS sequence and an equalization of the DSS readback sequence based on the coefficient cyclic equalizer vector. An unacceptable error signal indicates a need to adjust the coefficient cyclic equalizer vector to yield an acceptable comparison of the DSS sequence and an equalization of the DSS readback sequence based on the coefficient cyclic equalizer vector.
摘要翻译： 均衡器系数发生器接收DSS序列和DSS回读序列，DSS序列是通过读通道的DSS序列的信道处理的函数。 发生器产生作为DSS序列和DSS回读序列的函数的系数循环均衡器向量。 发生器还根据系数循环均衡器矢量，作为DSS序列与DSS回读序列的均衡的比较的函数产生误差信号。 不可接受的误差信号指示需要调整系数循环均衡器向量以产生DSS序列的可接受比较和基于系数循环均衡器向量的DSS回读序列的均衡。
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5.发明授权Method for an equalizer computation in a media system using a data set separator sequence 有权在使用数据集分隔符序列的媒体系统中进行均衡器计算的方法公开(公告)号：US07982997B2
公开(公告)日：2011-07-19
申请号：US12251373
申请日：2008-10-14
IPC分类号： G11B5/035
CPC分类号： G11B5/09 , G11B20/10009 , G11B20/10046 , G11B20/10481 , G11B2005/0013 , G11B2220/90
摘要： Provided is a method for receiving a DSS sequence and a DSS readback sequence, which is a function of a channel processing of the DSS sequence by a read channel. A coefficient cyclic equalizer vector is generated as a function of the DSS sequence and the DSS readback sequence. An error signal is generated as a function of a comparison of the DSS sequence and an equalization of the DSS readback sequence based on the coefficient cyclic equalizer vector. An unacceptable error signal indicates a need to adjust the coefficient cyclic equalizer vector to yield an acceptable comparison of the DSS sequence and an equalization of the DSS readback sequence based on the coefficient cyclic equalizer vector.
摘要翻译： 提供了一种用于接收DSS序列和DSS回读序列的方法，DSS序列是通过读取信道对DSS序列的信道处理的函数。 作为DSS序列和DSS回读序列的函数产生系数循环均衡器向量。 根据系数循环均衡器向量，作为DSS序列与DSS回读序列的均衡的比较的函数产生误差信号。 不可接受的误差信号指示需要调整系数循环均衡器向量以产生DSS序列的可接受比较和基于系数循环均衡器向量的DSS回读序列的均衡。
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6.发明授权Methods and systems for delay compensation in global PLL-based timing recovery loops 有权全球基于PLL的定时恢复循环中延迟补偿的方法和系统公开(公告)号：US07885030B2
公开(公告)日：2011-02-08
申请号：US12168723
申请日：2008-07-07
IPC分类号： G11B5/035
CPC分类号： H03L7/07 , G11B20/10009 , G11B20/10222 , G11B20/10425 , G11B20/1403 , G11B2220/90 , H03L7/085 , H03L7/22
摘要： A system in one embodiment includes a global PLL circuit comprising multiple inputs, each input being for receiving an error signal associated with an individual channel; and a delay compensation circuit coupled to the global PLL circuit. A method in one embodiment includes receiving multiple error signals, each error signal being associated with an individual channel; applying one or more delay compensation signals to the error signals; and outputting phase error output signals for each of the channels.
摘要翻译： 一个实施例中的系统包括包括多个输入的全局PLL电路，每个输入用于接收与单个信道相关联的错误信号; 以及耦合到全局PLL电路的延迟补偿电路。 一个实施例中的方法包括接收多个误差信号，每个误差信号与单个信道相关联; 对误差信号施加一个或多个延迟补偿信号; 并输出每个通道的相位误差输出信号。
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7.发明授权公开(公告)号：US08077764B2
公开(公告)日：2011-12-13
申请号：US12360777
申请日：2009-01-27
IPC分类号： H03H7/30
CPC分类号： H04L25/03299 , H04L25/03197 , H04L2025/03617
摘要： A 16-State adaptive NPML detector is provided for a tape drive which addresses weaknesses of a conventional fixed, 8-state EPR4 detector. Rather than having a fixed target channel, the detector is programmable to allow a range of target channels and can support “classical” partial response channels such as PR4 or EPR4 by programming predictor or whitening filter coefficients. In one embodiment, two filter coefficients may be set via XREG inputs or dynamically determined through the use of an LMS algorithm allowing the detector to adapt the predictor coefficients as data is being read. Another embodiment provides a detector for an EPR4 target in which the whitening filter has one coefficient. Components of the detection system include the detector itself, an LMS engine, a coefficient engine and a noise predictive or whitening filter. Coefficients from the LMS engine may be loaded or stored dynamically based upon conditions in the tape drive.
摘要翻译： 为磁带驱动器提供了16状态自适应NPML检测器，其解决了常规固定的8状态EPR4检测器的缺点。 不是具有固定的目标通道，检测器可编程以允许一定范围的目标通道，并且可以通过编程预测器或白化滤波器系数来支持“经典”部分响应通道，例如PR4或EPR4。 在一个实施例中，可以经由XREG输入来设置两个滤波器系数，或者通过使用LMS算法动态地确定，允许检测器在正在读取数据时调整预测器系数。 另一个实施例提供了一种用于EPR4目标的检测器，其中白化滤波器具有一个系数。 检测系统的组件包括检测器本身，LMS引擎，系数引擎和噪声预测或增白滤波器。 可以根据磁带驱动器中的条件动态地加载或存储来自LMS引擎的系数。
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8.发明申请DATA-DEPENDENT NOISE-PREDICTIVE MAXIMUM LIKELIHOOD DETECTION (DD-NPML) FOR MAGNETIC RECORDING 有权用于磁记录的数据依赖性噪声预测最大似然检测（DD-NPML）公开(公告)号：US20110242692A1
公开(公告)日：2011-10-06
申请号：US12753586
申请日：2010-04-02
IPC分类号： G11B27/36
CPC分类号： G11B20/10009 , G11B20/10046 , G11B20/10074 , G11B20/10175 , G11B20/10287 , G11B2220/90
摘要： In one embodiment, a method includes applying one or more whitening filters to an input stream of digitized samples from a magnetic data channel to produce a filtered sequence, performing one or more branch metric calculations to the filtered sequence to produce a branch metric, and applying a multi-state data-dependent noise-predictive maximum likelihood (DD-NPML) detector to the branch metric to produce an output stream. In another embodiment, a multi-channel data storage system includes a head for reading data from a storage medium, logic for applying one or more whitening filters to an input stream of digitized samples from a magnetic data channel to produce a filtered sequence, logic for performing one or more branch metric calculations to the filtered sequence to produce a branch metric, and logic for applying a multi-state DD-NPML detector to the branch metric to produce an output stream. Other systems and methods are described as well.
摘要翻译： 在一个实施例中，一种方法包括将一个或多个白化滤波器应用于来自磁数据信道的数字化样本的输入流，以产生经滤波的序列，对经滤波的序列执行一个或多个分支度量计算以产生分支度量，以及应用 用于产生输出流的分支度量的多状态数据相关噪声预测最大似然（DD-NPML）检测器。 在另一个实施例中，多通道数据存储系统包括用于从存储介质读取数据的头，用于将一个或多个白化滤波器应用于来自磁数据通道的数字化采样的输入流以产生滤波序列的逻辑，用于 对经滤波的序列执行一个或多个分支度量计算以产生分支度量，以及将多状态DD-NPML检测器应用于分支度量以产生输出流的逻辑。 还描述了其他系统和方法。
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公开(公告)号：US07760821B2
公开(公告)日：2010-07-20
申请号：US11558949
申请日：2006-11-13
申请人： Giovanni Cherubini , Evangelos S. Eleftheriou , Robert Allen Hutchins , Glen Alan Jaquette , Sedat Oelcer
发明人： Giovanni Cherubini , Evangelos S. Eleftheriou , Robert Allen Hutchins , Glen Alan Jaquette , Sedat Oelcer
IPC分类号： H04L27/06
CPC分类号： G11B20/10009 , G11B20/10046 , G11B20/10212 , H04B1/7085 , H04J2013/0037 , H04L25/0212 , H04L25/03038
摘要： Methods, apparatus and computer programs are provided for multiplication-free identification of the impulse response of an oversampled data channel. An input comprising a pseudo-random binary sequence of L symbols is supplied to the channel at a symbol rate of 1/T. A channel output is produced by sampling a channel output signal corresponding to the input with a sampling interval TS=(q/p)T, where q and p are relative prime integers with q
摘要翻译： 提供了方法，装置和计算机程序，用于对过采样数据信道的脉冲响应进行无乘法识别。 将包含L个符号的伪随机二进制序列的输入以符号率1 / T提供给信道。 通过以采样间隔TS =（q / p）T对与输入相对应的信道输出信号进行采样来产生信道输出，其中q和p是具有q
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10.发明申请System, method, and computer program product for characterizing media associated with data storage channels 有权用于表征与数据存储通道相关联的介质的系统，方法和计算机程序产品公开(公告)号：US20100172047A1
公开(公告)日：2010-07-08
申请号：US12350108
申请日：2009-01-07
CPC分类号： G11B20/10009 , G11B20/10055 , G11B20/10175 , G11B20/10222 , G11B2220/90
摘要： 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.
摘要翻译： 一个实施例中的系统包括用于接收回读信号的多个模拟输入，耦合到每个模拟输入的模数转换器，用于将回读信号转换成数字信号;耦合到模数转换器的输出的缓冲器，用于至少暂时地 存储数字信号，以及数字处理部分，其耦合到模数转换器的输出端，用于处理数字信号以从其重构数据。 一个实施例中的方法包括从磁头接收多个通道的模拟回读信号，将每个通道中的模拟信号转换成数字信号，缓冲数字信号，并输出缓冲的数字信号。 另一实施例中的方法包括从磁存储设备接收回读波形，减少回读波形的频率偏移，以及从回读波形生成同步的过采样波形。
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