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1. 发明授权

US5430744A Method and means for detecting partial response waveforms using a modified dynamic programming heuristic 失效
标题翻译：使用修改的动态规划启发式检测部分响应波形的方法和装置
公开(公告)号：US5430744A
公开(公告)日：1995-07-04
申请号：US129904
申请日：1993-09-30
申请人： Gerhard P. Fettweis , Razmik Karabed , Paul H. Siegel , Hemant K. Thapar
发明人： Gerhard P. Fettweis , Razmik Karabed , Paul H. Siegel , Hemant K. Thapar
IPC分类号： G06F11/10 , G11B20/18 , H03M13/23 , H03M13/41 , H04L25/08 , H03M13/00 , H04L25/34 , H04L25/49
CPC分类号： H03M13/6343 , H03M13/3961 , H03M13/41 , H03M13/4107 , H03M13/6502
摘要： A Viterbi decoder having a recursive processor modified to process each node in a trellis of a partial response coded signal to shift the branch metric additions over the node to effectuate compare, select, add operation order on the predecessor survivor metrics terminating in that node, to compare the metrics of the predecessor sequences terminating in the node, to select a survivor sequence, and to add the shifted branch metrics to the metric of the selected survivor sequence.
摘要翻译：一种具有递归处理器的维特比解码器，其被修改为处理部分响应编码信号的网格中的每个节点，以便通过该节点移动分支度量添加，以对在该节点终止的前导幸存者度量进行比较，选择，添加操作顺序，比较终止在节点中的前导序列的度量，以选择幸存者序列，并将移位的分支度量添加到所选存活序列的度量。

2. 发明授权

US5280489A Time-varying Viterbi detector for control of error event length 失效
标题翻译：用于控制误差事件长度的时变维特比检测器
公开(公告)号：US5280489A
公开(公告)日：1994-01-18
申请号：US869570
申请日：1992-04-15
申请人： Lyle J. Fredrickson , Razmik Karabed , James W. Rae , Paul H. Siegel , Hemant K. Thapar , Roger W. Wood
发明人： Lyle J. Fredrickson , Razmik Karabed , James W. Rae , Paul H. Siegel , Hemant K. Thapar , Roger W. Wood
IPC分类号： H03M13/31 , G06F11/20 , H03M13/12
CPC分类号： H03M13/31
摘要： A method and apparatus for detecting spectral null sequences of a spectrally-constrained code on a noisy communications channel. From a Viterbi detector with a trellis structure comprising a plurality of states and edges, predetermined ones of the states and edges in the trellis structure are deleted at preselected times modulo N, such as times .phi. modulo N and/or at intermediate times m modulo N, where m=.phi., thereby to create a time-varying trellis structure for limiting the maximum length of dominant error events. The deleted edges are generally those edges which would have entered or emanated from the deleted states if they were not deleted. The trellis structure may be a so-called systolic structure, in which case the spectral null sequences are preferably DC-free or Nyquist free.
摘要翻译：一种用于检测噪声通信信道上的频谱约束码的频谱零序列的方法和装置。从具有包括多个状态和边缘的网格结构的维特比检测器，网格结构中的预定的状态和边缘被预选为时间N，例如时间（phi）模N和/或中间时间m 模N，其中m =（phi），从而产生用于限制主要误差事件的最大长度的时变网格结构。删除的边通常是那些从删除状态输入或发出的边缘，如果它们没有被删除。网格结构可以是所谓的收缩结构，在这种情况下，光谱无效序列优选不含DC或奈奎斯特。

3. 发明授权

US5537424A Matched spectral null codes with partitioned systolic trellis structures 失效
标题翻译：具有分割收缩网格结构的匹配的谱空代码
公开(公告)号：US5537424A
公开(公告)日：1996-07-16
申请号：US289811
申请日：1994-08-12
申请人： Razmik Karabed , James W. Rae , Paul H. Siegel , Hemant K. Thapar
发明人： Razmik Karabed , James W. Rae , Paul H. Siegel , Hemant K. Thapar
IPC分类号： H03M13/31 , H03M13/41 , H04L25/497 , H03M13/12
CPC分类号： H03M13/6343 , H03M13/31 , H03M13/3961 , H03M13/41 , H03M13/4107 , H03M13/4169 , H03M13/6502 , H04L25/497
摘要： Apparatus and method for transmitting spectral null sequences of a spectrally-constrained code over a partial response channel. A Viterbi detector receives the sequences from the channel and has a time-varying detector trellis structure derived from a running-digital-sum (RDS) trellis structure that requires each one of a set of quasicatastrophic sequences to be generated only from a trellis state corresponding to a respective preselected unique RDS value.
摘要翻译：用于在部分响应信道上发送频谱约束码的频谱零序列的装置和方法。维特比检测器从信道接收序列，并且具有从运行数字和（RDS）网格结构导出的时变检测器网格结构，其需要仅从对应的网格状态产生一组准基因阵列序列中的每一个到相应的预选的唯一RDS值。

4. 发明授权

US5548600A Method and means for generating and detecting spectrally constrained coded partial response waveforms using a time varying trellis modified by selective output state splitting 失效
标题翻译：使用通过选择性输出状态分割修改的时变网格来生成和检测频谱约束的编码部分响应波形的方法和装置
公开(公告)号：US5548600A
公开(公告)日：1996-08-20
申请号：US316597
申请日：1994-09-29
申请人： Lisa Fredrickson , Razmik Karabed , Paul H. Siegel , Hemant K. Thapar
发明人： Lisa Fredrickson , Razmik Karabed , Paul H. Siegel , Hemant K. Thapar
IPC分类号： H03M13/31 , H03M13/41 , H04L25/497 , G06F11/10 , H03M13/12
CPC分类号： H03M13/31 , H03M13/3961 , H03M13/41 , H03M13/4107 , H03M13/4169 , H03M13/6343 , H03M13/6502 , H04L25/497
摘要： A method and means for detecting spectral null sequences of a spectrally-constrained code at the output of a noisy communications channel by tracking the spectral content of said sequences with a Viterbi detector using an N stage trellis and mapping each spectral null sequence to a unique path of acyclic successive states and edges through said trellis by selectively outsplitting counterpart states at preselected times modulo N in said trellis such that no pair of unique paths support the same spectral null sequence.
摘要翻译：一种用于通过使用N阶网格跟踪具有维特比检测器的所述序列的频谱内容并将每个频谱零序列映射到唯一路径来检测噪声通信信道的输出处的频谱约束码的频谱零序列的方法和装置通过在所述网格中以预选的时间模N选择性地外切对应状态，使得没有一对唯一路径支持相同的频谱无效序列，从而使非循环连续状态和边缘穿过所述网格。

5. 发明授权

US5497384A Permuted trellis codes for input restricted partial response channels 失效
标题翻译：输入限制部分响应通道的格子码
公开(公告)号：US5497384A
公开(公告)日：1996-03-05
申请号：US174904
申请日：1993-12-29
申请人： Lisa Fredrickson , Razmik Karabed , Paul H. Siegel , Hemant K. Thapar
发明人： Lisa Fredrickson , Razmik Karabed , Paul H. Siegel , Hemant K. Thapar
IPC分类号： H03M13/25 , H03M13/31 , H03M13/41 , G06F11/10 , H03M13/12
CPC分类号： H03M13/6343 , H03M13/25 , H03M13/31 , H03M13/41 , H03M13/6502
摘要： Maximum likelihood detection of a trellis code using a Viterbi detector constructed from a time-varying trellis structure that is associated with a partial response channel and consists of connected trellises with periodically repeated patterns of nodes and subtrellises of said trellises. Each subtrellis has nodes representing a current state of the channel and value of a predetermined tracked attribute. A survivor metric and a survivor sequence from a node at the end of one subtrellis are reassigned to a node at the beginning of an adjacent subtrellis having a different value of the tracked attribute for increasing minimum distance properties, reducing error event length and improving code constraints for timing and gain control. The one subtrellis and adjacent subtrellis may be within a single trellis or in adjacent trellises.
摘要翻译：使用由与部分响应信道相关联的时变网格结构构成的维特比检测器的网格码的最大似然检测，并且由具有所述网格的节点和子树的周期性重复模式的连接网格组成。每个子伞具有表示通道的当前状态和预定跟踪属性的值的节点。来自一个子结尾处的节点的幸存者度量和幸存者序列被重新分配给具有跟踪属性的不同值的相邻子树的开始处的节点，用于增加最小距离属性，减少错误事件长度和改进代码约束用于定时和增益控制。一个子伞和相邻的子伞可以在单个网格内或相邻的网格中。

6. 发明授权

US4651320A Inband coding of secondary data 失效
标题翻译：辅助数据的带内编码
公开(公告)号：US4651320A
公开(公告)日：1987-03-17
申请号：US685487
申请日：1984-12-24
申请人： Hemant K. Thapar
发明人： Hemant K. Thapar
IPC分类号： H04B17/00 , H04L27/34 , H04L3/00
CPC分类号： H04L27/3472
摘要： In a system for communicating primary and secondary data from a transmitter to a receiver, each of a first plurality of primary data word values is communicated by the transmitter by transmitting an individual channel symbol associated with that value, while each of at least two other primary data word values are communicated by transmitting a selected one of at least two other channel symbols associated with that primary data word value. A predetermined one of the two channel symbols associated with the first primary data word value is transmitted only when secondary data having a first value is to be communicated, and a predetermined one of the two channel symbols associated with the second primary data word value is transmitted only when secondary data having a second value is to be communicated. In the receiver, both the primary and secondary data word values are recovered from the channel symbols thus transmitted.
摘要翻译：在用于将主数据和次要数据从发送器传送到接收器的系统中，第一多个主数据字值中的每一个由发送器通过发送与该值相关联的单个信道符号来传送，而至少两个其他主数据通过发送与该主数据字值相关联的至少两个其他信道符号中的所选择的一个来传送数据字值。与第一主数据字值相关联的两个信道符号中的预定的一个信号符号只有在要传送具有第一个值的次要数据时被传送，并且传输与第二主数据字值相关联的两个信道符号中的预定的一个信道符号只有当要传达具有第二值的二次数据时。在接收机中，主数据字和辅助数据字值都从这样发送的信道符号恢复。

7. 发明授权

US4534040A Method and apparatus for coding a binary signal 失效
标题翻译：用于对二进制信号进行编码的方法和装置
公开(公告)号：US4534040A
公开(公告)日：1985-08-06
申请号：US455502
申请日：1983-01-04
申请人： Hemant K. Thapar
发明人： Hemant K. Thapar
IPC分类号： H03M13/25 , H04L27/34 , H04L3/00
CPC分类号： H04L27/3433 , H03M13/25 , H04L27/3494
摘要： An input bit sequence is encoded for transmission on a QAM carrier by dividing a scrambled version of the input sequence into groups of N consecutive bits. Each group is then subdivided into first and second subsets of r and r.sup.1 bits, where r+r.sup.1 =N. At least one of the bits in the first subset is applied to a finite state machine (such as a convolution encoder) which is arranged to expand the applied bits by at least one additional bit, in accordance with a prescribed logic arrangement. At least one bit in the second subset is processed similarly but independently, using a different finite state machine, or by time sharing a single finite state encoder. The expanded bit subsets, which include at least r+1 and r.sup.1 +1 bits, respectively, are then mapped into in-phase and quadrature symbols such that the minimum euclidean distance for an error event is larger than that obtained from an uncoded system. The symbols to be transmitted are then filtered and the filter output is modulated using conventional QAM methods.
摘要翻译：通过将输入序列的加扰版本划分成N个连续比特的组来对输入比特序列进行编码，用于在QAM载波上传输。然后将每个组细分为r和r1位的第一和第二子集，其中r + r1 = N。第一子集中的位中的至少一个被应用于有限状态机（例如卷积编码器），其被布置为根据规定的逻辑布置将所施加的位扩展至少一个附加位。第二子集中的至少一位被类似地处理，但是独立地使用不同的有限状态机，或通过时间共享单个有限状态编码器。分别包括至少r + 1和r1 + 1位的扩展位子集然后被映射到同相和正交符号中，使得用于错误事件的最小欧几里德距离大于从未编码系统获得的最小欧几里德距离。然后将要发送的符号进行滤波，并使用常规QAM方法调制滤波器输出。

8. 发明授权

US5949820A Method for optimizing an equalization and receive filter 失效
标题翻译：优化均衡和接收滤波器的方法
公开(公告)号：US5949820A
公开(公告)日：1999-09-07
申请号：US690950
申请日：1996-08-01
申请人： Shih-Ming Shih , Hemant K. Thapar
发明人： Shih-Ming Shih , Hemant K. Thapar
IPC分类号： G05F3/22 , G11B5/00 , G11B5/035 , G11B20/10 , G11B20/18 , G11B33/14 , H03F1/30 , H03H11/04 , H03H11/12 , H03H11/50 , H03H21/00 , H03H7/30
CPC分类号： G11B20/10055 , G05F3/225 , G11B20/10009 , G11B20/10481 , H03H11/1291 , H03H21/0001 , G11B2005/001 , G11B33/14 , G11B5/035 , H03H21/0012
摘要： Apparatus and Methods are disclosed for adaptively optimizing an ER filter in a readback system of a storage device, such as a disk drive. A sample value is read from the storage device and an error measure is calculated between the sample value and an ideal value. Pole parameters and zeros of the ER filter are modified to minimize the ER filter. The apparatus and methods disclosed can function with customer data to adaptively optimize the ER filter in real time during normal operation of the storage device. Furthermore, temperature compensation circuits are disclosed to compensate for temperature dependencies in the ER filter.
摘要翻译：公开了用于在诸如磁盘驱动器的存储设备的回读系统中自适应地优化ER滤波器的装置和方法。从存储设备读取样本值，并在样本值和理想值之间计算误差测量值。 ER滤波器的极参数和零点被修改以使ER滤波器最小化。所公开的装置和方法可以与客户数据一起工作，以在存储装置的正常操作期间实时自适应地优化ER滤波器。此外，公开了温度补偿电路来补偿ER滤波器中的温度依赖性。

9. 发明授权

US5914989A PRML system with reduced complexity maximum likelihood detector 失效
标题翻译： PRML系统具有降低的复杂度最大似然检测器
公开(公告)号：US5914989A
公开(公告)日：1999-06-22
申请号：US800989
申请日：1997-02-18
申请人： Hemant K. Thapar , Shih-Ming Shih , Kwok W. Yeung
发明人： Hemant K. Thapar , Shih-Ming Shih , Kwok W. Yeung
IPC分类号： G11B20/14 , G11B20/10 , G11B20/18 , H03G3/20 , H03M13/23 , H03M13/39 , H04L1/00 , H03M13/12
CPC分类号： G11B20/10009
摘要： A less complex maximum likelihood detector can be implemented in a partial response maximum likelihood (PRML) system without degrading system performance by saturating y values from a gain control loop to a smaller range before the y values are supplied to the maximum likelihood detector. A quantity "D" of a maximum likelihood detector operating in accordance with a partial response scheme has a particular relationship with respect to the maximum (ymax) of the y input values processed by the maximum likelihood detector. In some embodiments, y values from a gain control loop are saturated from a first larger range (defined by ymaxreal) to a second smaller range (defined by a value SAT) which is at least as great as the ymax of the ideal input signal (ymaxideal) for the partial response scheme. The saturated y values are provided to the maximum likelihood detector. The D of the maximum likelihood detector (given the partial response scheme and the smaller range of y values) is in a different "two to the power of an integer range" than the D would have been given the same partial response scheme but the larger range of y values.
摘要翻译：可以在部分响应最大似然（PRML）系统中实施不太复杂的最大似然检测器，而不会在将y值提供给最大似然检测器之前将y值从增益控制环饱和到更小的范围，而不降低系统性能。根据部分响应方案操作的最大似然检测器的数量“D”与由最大似然检测器处理的y个输入值的最大值（ymax）具有特定的关系。在一些实施例中，来自增益控制环路的y值从至少与理想输入信号的ymax一样大的第一较大范围（由ymaxreal定义）饱和到第二较小范围（由SAT定义） ymaxideal）用于部分响应方案。饱和的y值被提供给最大似然检测器。最大似然检测器（给定部分响应方案和y值的较小范围）的D与D给出相同的部分响应方案不同的“二到整数范围的功率”，但是较大 y值的范围。

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