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    Filtering a read signal to attenuate secondary pulses caused by pole tips of a thin film magnetic read head
    4.
    发明授权
    Filtering a read signal to attenuate secondary pulses caused by pole tips of a thin film magnetic read head 失效
    滤除读取信号以衰减由薄膜磁头读取头的极尖引起的次脉冲

    公开(公告)号：US5623377A

    公开(公告)日：1997-04-22

    申请号：US222666

    申请日：1994-04-04

    申请人： Richard T. Behrens ,  Neal Glover ,  Trent O. Dudley ,  Alan J. Armstrong ,  Christopher P. Zook ,  William G. Bliss

    发明人： Richard T. Behrens ,  Neal Glover ,  Trent O. Dudley ,  Alan J. Armstrong ,  Christopher P. Zook ,  William G. Bliss

    IPC分类号： G11B5/09 ,  G11B20/10 ,  H03H17/02 ,  H03H17/06 ,  H04B3/06 ,  G11B5/035

    CPC分类号： H03H17/06 ,  G11B20/10009 ,  G11B5/09 ,  H03H17/02

    摘要： A filter for compensating discrete secondary pulse formations associated with a data stream of discrete main pulses produced from data read from magnetic media. The filter's impulse response comprises a center coefficient with side compensating coefficients for attenuating the secondary pulses when the input signal is convolved with the impulse response. The magnitude and delay of the compensation coefficients are programmable and are adaptively adjusted to optimize the impulse response for a given environment. In a traditional FIR embodiment, two delay lines are used to generate the two programmable delays between the center coefficient and side compensation coefficients. In the preferred embodiment, an IIR filter provides the two programmable delays using only one delay line thereby reducing the size and cost of the circuit. Also in the preferred embodiment, the data stream is interleaved into an even and odd data stream and processed in parallel by two filters in order to double the throughput. Further, the pre-cursor correcting portion of the filter can be disabled in order to avoid delaying the data stream while still canceling the post-cursor secondary pulses. The filter also comprises attenuation and adder means to match the coincident sample values in amplitude and add them to substantially eliminate the effect of the secondary pulses in the discrete data stream.

    摘要翻译： 用于补偿与从磁介质读取的数据产生的离散主脉冲的数据流相关联的离散次级脉冲形成的滤波器。 滤波器的脉冲响应包括具有侧补偿系数的中心系数，用于当输入信号与脉冲响应卷积时衰减次级脉冲。 补偿系数的幅度和延迟可编程，并进行自适应调整，以优化给定环境的脉冲响应。 在传统的FIR实施例中，使用两条延迟线来产生中心系数和侧面补偿系数之间的两个可编程延迟。 在优选实施例中，IIR滤波器仅使用一个延迟线提供两个可编程延迟，从而减小电路的尺寸和成本。 同样在优选实施例中，数据流被交织成偶数和奇数数据流，并且由两个滤波器并行处理，以使吞吐量翻倍。 此外，可以禁用滤波器的前光标校正部分，以避免在仍然取消后光标次级脉冲的同时延迟数据流。 滤波器还包括衰减和加法器装置，以使幅度上重合的采样值相匹配，并将它们相加，以基本上消除离散数据流中次级脉冲的影响。

    Fault tolerant sync mark detector enabled relative to a frequency of an acquisition preamble for sampled amplitude recording
    5.
    发明授权
    Fault tolerant sync mark detector enabled relative to a frequency of an acquisition preamble for sampled amplitude recording 失效
    容错同步标记检测器相对于采样幅度记录的采集前导码的频率启用

    公开(公告)号：US5729396A

    公开(公告)日：1998-03-17

    申请号：US440268

    申请日：1995-05-12

    申请人： Trent O. Dudley ,  Richard T. Behrens ,  Christopher P. Zook

    发明人： Trent O. Dudley ,  Richard T. Behrens ,  Christopher P. Zook

    IPC分类号： G11B5/012 ,  G11B20/10 ,  G11B20/14 ,  G11B27/30 ,  G11B5/09

    CPC分类号： G11B20/10055 ,  G11B20/10009 ,  G11B20/10037 ,  G11B20/1403 ,  G11B27/30 ,  G11B27/3027 ,  G11B5/012 ,  G11B2020/1476

    摘要： A sampled amplitude read channel reads data from a magnetic medium by detecting digital data from a sequence of discrete time sample values generated by sampling an analog read signal from a read head positioned over the magnetic medium. The digital data comprises a preamble field followed by a sync mark followed by a data field. Timing recovery in the read channel synchronizes to a phase and frequency of the preamble field and a sync detector detects the sync mark in order to frame operation of an RLL decoder for decoding the detected data field. To decrease the probability of early misdetection, the sync mark is chosen to have minimum correlation with shifted versions of the sync mark concatenated with the preamble field. To further increase the fault tolerance, the sync mark detector is enabled by timing recovery relative to the end of the preamble field. A state machine in timing recovery generates expected sample values used to acquire the preamble field, and a current state of the state machine indicates when the preamble ends relative to a predetermined clock interval. In this manner, the search for an appropriate sync mark need only look for minimum correlation during shifts at the predetermined clock interval, thereby increasing the fault tolerant characteristic of the sync mark.

    摘要翻译： 采样幅度读取通道从通过从位于磁性介质上的读取头采样模拟读取信号而产生的离散时间采样值的序列中检测数字数据，从磁性介质读取数据。 数字数据包括前同步码字段，随后是同步标记，后跟数据字段。 读通道中的定时恢复与前同步码字段的相位和频率同步，并且同步检测器检测同步标记，以便对RLL解码器进行帧操作，以对检测到的数据字段进行解码。 为了降低早期错误检测的可能性，选择同步标记与与前同步码字段连接的同步标记的移位版本具有最小相关性。 为了进一步增加容错能力，同步标记检测器通过相对于前同步码字段结束的定时恢复来启用。 定时恢复中的状态机产生用于获取前导字段的预期采样值，并且状态机的当前状态指示前导码相对于预定时钟间隔何时结束。 以这种方式，搜索适当的同步标记仅需要在预定时钟间隔期间寻找在移位期间的最小相关性，从而增加同步标记的容错特性。

    Disk storage system employing error detection and correction of channel coded data, interpolated timing recovery, and retroactive/split-segment symbol synchronization
    6.
    发明授权
    Disk storage system employing error detection and correction of channel coded data, interpolated timing recovery, and retroactive/split-segment symbol synchronization 失效
    磁盘存储系统采用通道编码数据的错误检测和校正，内插定时恢复和追溯/分段符号同步

    公开(公告)号：US6009549A

    公开(公告)日：1999-12-28

    申请号：US856885

    申请日：1997-05-15

    申请人： William G. Bliss ,  Christopher P. Zook ,  Richard T. Behrens

    发明人： William G. Bliss ,  Christopher P. Zook ,  Richard T. Behrens

    IPC分类号： G11B5/012 ,  G11B20/10 ,  G11B20/14 ,  G11B20/18 ,  G11B27/30 ,  C11C29/00 ,  G11B5/09

    CPC分类号： G11B20/10055 ,  G11B20/10009 ,  G11B20/1426 ,  G11B20/1833 ,  G11B27/3027 ,  G11B2020/1476 ,  G11B5/012

    摘要： A disk storage system is disclosed wherein user data received from a host system is first encoded according to a first channel code having a high code rate, and then encoded according to an ECC code, such as a Reed-Solomon code, wherein the ECC redundancy symbols are encoded according to a second channel code having low error propagation. In the preferred embodiment, the first channel code is a RLL (d,k) code having a long k constraint which allows for longer block lengths (and higher code rates). During read back, a synchronous read channel samples the analog read signal a synchronously and interpolates the asynchronous sample values to generate sample values substantially synchronized to the baud rate. In contrast to conventional synchronous-sampling timing recovery, interpolated timing recovery can tolerate a longer RLL k constraint because it is less sensitive to noise in the read signal and not affected by process variations in fabrication. Additionally, a trellis sequence detector detects an estimated binary sequence from the synchronous sample values, wherein a state transition diagram of the trellis detector is configured according to the code constraints of the first and second channel codes. The estimated binary sequence output by the sequence detector is buffered in a data buffer to facilitate the error detection and correction process, and to allow for retroactive and split-segment symbol synchronization using multiple sync marks.

    摘要翻译： 公开了一种磁盘存储系统，其中根据具有高码率的第一信道码首先对从主机系统接收的用户数据进行编码，然后根据诸如Reed-Solomon码的ECC码进行编码，其中ECC冗余 符号根据具有低误差传播的第二信道码进行编码。 在优选实施例中，第一信道码是具有长k约束的RLL（d，k）码，其允许更长的码块长度（和较高码率）。 在读回期间，同步读通道同步地对模拟读取信号进行采样，并内插异步采样值，以生成基本上与波特率同步的采样值。 与传统的同步采样定时恢复相比，内插定时恢复可以容忍较长的RLL k约束，因为它对读取信号中的噪声不太敏感，并且不受制造过程变化的影响。 另外，网格序列检测器根据同步采样值检测估计的二进制序列，其中根据第一和第二信道码的编码约束配置网格检测器的状态转移图。 由序列检测器输出的估计的二进制序列被缓冲在数据缓冲器中，以便于错误检测和校正过程，并允许使用多个同步标记进行追溯和分段符号同步。

    Servo decoder for decoding an error correcting servo code recorded on a disc storage medium
    7.
    发明授权
    Servo decoder for decoding an error correcting servo code recorded on a disc storage medium 失效
    伺服解码器，用于解码记录在盘存储介质上的纠错伺服码

    公开(公告)号：US6005727A

    公开(公告)日：1999-12-21

    申请号：US790038

    申请日：1997-01-28

    申请人： Richard T. Behrens ,  Christopher P. Zook ,  David E. Reed ,  Stephen A. Turk

    发明人： Richard T. Behrens ,  Christopher P. Zook ,  David E. Reed ,  Stephen A. Turk

    IPC分类号： G11B5/55 ,  G11B5/596 ,  G11B7/007 ,  G11B21/08 ,  G11B21/10 ,  G11B27/30 ,  G11B5/09

    CPC分类号： G11B7/00745 ,  G11B21/083 ,  G11B21/106 ,  G11B27/3027 ,  G11B5/553 ,  G11B5/59655 ,  G11B5/59688 ,  G11B5/5547

    摘要： A servo decoder is disclosed for disc storage systems that operates according to a novel coding scheme capable of accurately decoding detected codewords representing servo track address during seek operations, even when the recording head flies between two adjacent tracks, and capable of correcting errors in the detected codedwords caused by noise in the read signal, such as inter-symbol interference. In a first embodiment, the coding scheme comprises an error correcting code (ECC) capable of correcting a predetermined number of bit errors in the detected codewords. To achieve the equivalent effect of a conventional Gray code, the codewords are arranged such that adjacent track addresses differ by a number of bits equal to the minimum distance of the ECC code. In a second embodiment, the servo code corrects certain minimum distance error events associated with a trellis type sequence detector. To achieve the equivalent effect of a conventional Gray code in this embodiment, the codewords are arranged such that adjacent track addresses differ by a number of bits relative to the minimum distance error events corrected. In this manner, when the recording head spans two adjacent tracks during a seek operation, the ambiguity in the detected codeword will be resolved in favor of one of the adjacent track addresses. Further, due to the error correcting capabilities of the code, the present invention improves the performance of servo seeking and tracking operations, and allows the servo data to be recorded at a higher density.

    摘要翻译： 公开了一种用于盘存储系统的伺服解码器，该盘存储系统根据能够在搜索操作期间精确地解码表示伺服轨迹地址的检测码字的新型编码方案进行操作，即使当记录头在两个相邻的轨道之间飞行时，也能够校正检测到的错误 读取信号中由噪声引起的编码字，如符号间干扰。 在第一实施例中，编码方案包括能够校正检测码字中预定数量的位错误的纠错码（ECC）。 为了实现常规格雷码的等效效果，码字被布置成使得相邻轨道地址与等于ECC码的最小距离的位数相差。 在第二实施例中，伺服代码校正与网格型序列检测器相关联的某些最小距离误差事件。 为了实现本实施例中常规格雷码的等效效果，码字被布置成使得相邻轨道地址相对于校正的最小距离误差事件相差多个位。 以这种方式，当在搜索操作期间记录头跨越两个相邻轨道时，检测到的码字中的模糊度将被解析为有利于相邻轨道地址之一。 此外，由于代码的纠错能力，本发明提高了伺服寻找和跟踪操作的性能，并允许以更高的密度记录伺服数据。

    PR4 sampled amplitude read channel employing an NRZI write modulator and a PR4/NRZI converter
    8.
    发明授权
    PR4 sampled amplitude read channel employing an NRZI write modulator and a PR4/NRZI converter 失效
    PR4采样幅度读通道采用NRZI写调制器和PR4 / NRZI转换器

    公开(公告)号：US5786950A

    公开(公告)日：1998-07-28

    申请号：US681694

    申请日：1996-07-29

    申请人： Christopher P. Zook ,  David E. Reed

    发明人： Christopher P. Zook ,  David E. Reed

    IPC分类号： G11B5/09 ,  G11B20/10

    CPC分类号： G11B20/10055 ,  G11B20/10009 ,  G11B20/10037 ,  G11B20/10175 ,  G11B5/09

    摘要： A PR4 sampled amplitude read channel is disclosed which employs an NRZI modulator for writing encoded user data directly to a magnetic disc storage medium instead of using a conventional 1/(1+D.sup.2) precoder. This avoids the ambiguous initial state of the precoder and allows the read channel to directly control the magnetic flux transitions written onto the disc. Upon read back, a PR4 sequence detector outputs a preliminary data sequence which is converted back into the NRZI domain and then decoded into an estimated user data sequence.

    摘要翻译： 公开了一种PR4采样幅度读取通道，其采用NRZI调制器来将编码的用户数据直接写入磁盘存储介质，而不是使用常规的1 /（1 + D2）预编码器。 这避免了预编码器的不明确的初始状态，并允许读通道直接控制写入光盘的磁通转换。 在读回时，PR4序列检测器输出初步数据序列，其被转换回NRZI域，然后被解码为估计的用户数据序列。

    Servo track address channel code for d=1 magnetic recording
    9.
    发明授权
    Servo track address channel code for d=1 magnetic recording 失效
    d = 1磁记录的伺服磁道地址通道代码

    公开(公告)号：US07126775B1

    公开(公告)日：2006-10-24

    申请号：US08678011

    申请日：1996-07-10

    申请人： Christopher P. Zook

    发明人： Christopher P. Zook

    IPC分类号： G11B5/09 ,  G11B5/596

    CPC分类号： G11B5/59644 ,  G11B20/10046 ,  G11B20/10194 ,  G11B20/10296 ,  G11B20/22 ,  G11B27/3027 ,  G11B2220/2516 ,  H03M7/16 ,  H03M7/46

    摘要： A rate ½, d=1 channel code encodes a Gray code servo track address into channel data recorded on a magnetic disk; a d=1 Viterbi sequence detector detects the recorded servo track address upon read back; a cost effective d=1 decoder decodes the recorded servo track address into its Gray code representation; and a 1/1+D filter decodes the Gray code track address into its binary representation. The channel encoding scheme increases the data density of the storage system due to the d=1 constraint and use of the Viterbi sequence detector. Further, the implementation advantageously uses the Viterbi sequence detector already provided in a read channel for detecting user data, and the cost and complexity of the decoder is reduced by encoding/decoding the Gray code track address in sections of five bits.

    摘要翻译： 速率½，d = 1通道代码将格雷码伺服轨迹地址编码到记录在磁盘上的通道数据; d = 1维特比序列检测器在读回时检测记录的伺服轨迹地址; 成本有效的d = 1解码器将记录的伺服轨道地址解码为其格雷码表示; 并且1/1 + D滤波器将格雷码轨迹地址解码为其二进制表示。 信道编码方案由于d = 1约束和维特比序列检测器的使用而增加了存储系统的数据密度。 此外，该实现有利地使用已经在读通道中提供的维特比序列检测器来检测用户数据，并且通过以5比特的部分对格雷码轨道地址进行编码/解码来降低解码器的成本和复杂度。

    Error detection convolution code and post processor for correcting dominant error events of a trellis sequence detector in a sampled amplitude read channel for disk storage systems
    10.
    发明授权
    Error detection convolution code and post processor for correcting dominant error events of a trellis sequence detector in a sampled amplitude read channel for disk storage systems 有权
    错误检测卷积码和后处理器，用于校正磁盘存储系统采样振幅读取通道中网格序列检测器的主要错误事件

    公开(公告)号：US06516443B1

    公开(公告)日：2003-02-04

    申请号：US09499930

    申请日：2000-02-08

    申请人： Christopher P. Zook

    发明人： Christopher P. Zook

    IPC分类号： H03M1300

    CPC分类号： G11B20/10055 ,  G11B20/10009 ,  G11B20/10296 ,  G11B20/18

    摘要： In a disk storage system for digital computers (e.g., optical or magnetic disk drives) a sampled amplitude read channel is disclosed comprising a convolutional code channel encoder for encoding check bits into channel data recorded to a disk storage medium, a trellis sequence detector for detecting a preliminary sequence from read signal sample values generated during read back, a convolutional code syndrome generator for generating an error syndrome from the preliminary sequence, and a post processor for evaluating the error syndrome to detect and correct errors made by the trellis sequence detector. The post processor remodulates the preliminary sequence output by the trellis sequence detector into a sequence of estimated sample values which are subtracted from the actual read signal sample values to form a sequence of sample errors. When the error syndrome indicates the presence of an error in the preliminary sequence, the post processor processes the sample errors to determine the most likely location of the error and corrects it. The convolution code provides a significant performance gain due to its high rate and capacity to detect several of the dominant error events associated with the trellis sequence detector.

    摘要翻译： 在用于数字计算机（例如，光盘或磁盘驱动器）的磁盘存储系统中，公开了一种采样幅度读取通道，其包括卷积码通道编码器，用于将检查位编码到记录到盘存储介质的通道数据中，格子序列检测器用于检测 从回读期间产生的读取信号样本值的初步序列，用于从初步序列生成错误综合征的卷积码校验发生器，以及用于评估误差综合征以检测和校正由格子序列检测器产生的错误的后处理器。 后处理器将网格序列检测器的初始序列输出重新调整为从实际读取信号采样值中减去的估计样本值序列，以形成一系列样本误差。 当错误综合征指示初步序列中存在错误时，后处理器处理样本误差以确定误差的最可能位置并对其进行校正。 卷积码提供了显着的性能增益，这是由于其高速率和容量来检测与格子序列检测器相关联的几个主要误差事件。