公开(公告)号：US5432803A

公开(公告)日：1995-07-11

申请号：US876324

申请日：1992-04-30

申请人： Qingli Liu ,  Xiangyang Chen ,  Lise Vanterpool ,  Andrew Sendyk

发明人： Qingli Liu ,  Xiangyang Chen ,  Lise Vanterpool ,  Andrew Sendyk

IPC分类号： H03M13/41 ,  G06F11/10

CPC分类号： H03M13/6505 ,  H03M13/3961 ,  H03M13/41 ,  H03M13/4107 ,  H03M13/4169

摘要： A maximum likelihood decoding system includes a branch metric processor which calculates only one of four branch metrics associated with branches leading to two consecutive states S.sub.j and S.sub.+1, where j is even. The system determines the remaining three metrics by producing a second branch metric by manipulating the first branch metric using simple binary operations and assigns the first and second metrics to the second and first branches, respectively, leading to the odd state. The system next retrieves associated path metrics from a path metric memory which stores the information in locations accessed by addresses related to identifiers associated with the branch initial states. After the system selects a surviving path for each end state, it stores in a path memory location associated with the end state information identifying the previous state on the surviving path. Thereafter, during trace back, the system uses the identifier of a known end state to address the path memory and retrieve the information identifying a previous state on the path. The system assigns data values to the branches of the most likely path as soon as it identifies the states on the path, since all branches leading to an even state are associated with a "ZERO" data bit and all branches leading to an odd state are associated with a "ONE" data bit.

摘要翻译： 最大似然解码系统包括分支度量处理器，其仅计算与分支导致两个连续状态Sj和S + 1相关联的四个分支度量中的一个，其中j是偶数。 该系统通过使用简单的二进制操作来操纵第一分支度量来产生第二分支度量来确定剩余的三个度量，并且分别将第一和第二度量分配给导致奇数状态的第二和第一分支。 系统接下来从路径度量存储器中检索相关联的路径度量，路径度量存储器将信息存储在通过与分支初始状态相关联的标识符相关的地址访问的位置中。 在系统为每个结束状态选择幸存路径之后，它存储在与存活路径上标识先前状态的结束状态信息相关联的路径存储器位置。 此后，在回溯期间，系统使用已知结束状态的标识符来寻址路径存储器并且检索标识路径上的先前状态的信息。 一旦识别路径上的状态，系统会将数据值分配给最可能路径的分支，因为导致均匀状态的所有分支都与“零”数据位相关联，导致奇数状态的所有分支都是 与“ONE”数据位相关联。

公开(公告)号：US5263053A

公开(公告)日：1993-11-16

申请号：US856526

申请日：1992-03-24

申请人： Yongbing Wan ,  Qingli Liu ,  Andrew Sendyk

发明人： Yongbing Wan ,  Qingli Liu ,  Andrew Sendyk

IPC分类号： H04L25/03 ,  H04B15/00

CPC分类号： H04L25/03292

摘要： The channel-impulse-response estimator (44') in a maximum-likelihood-sequence-estimation receiver produces channel-model parameters for a model that produces outputs not only for symbol times but also for intermediate times between the symbol times. A symbol-sequence-derivation circuit (42') determines the most-likely sequence on the basis of metrics computed from the differences between the received signal and the responses of the model to candidate sequences not only at the symbol times but also at the intermediate times. An interpolator (100) receives the symbol decisions from the symbol-sequence-derivation circuit (42') and generates intermediate values from them by simulating the Nyquist filter formed by the concatenation of pulse-shaping filters (22 and 24) in the transmitter and matched filters (36 and 37) in the receiver. The channel-impulse-response estimator (44') uses these values together with the derived-symbol values as inputs to its updating process to maintain the model.

摘要翻译： 最大似然序列估计接收机中的信道脉冲响应估计器（44'）为不仅用于符号时间而且也用于符号时间之间的中间时间产生输出的模型产生信道模型参数。 符号序列导出电路（42'）基于从接收信号和模型与候选序列的响应之间的差异计算的度量来确定最可能的序列，不仅在符号时间，而且在中间 次 插值器（100）从符号序列导出电路（42'）接收符号判定，并通过模拟由发射机中的脉冲整形滤波器（22和24）的级联形成的奈奎斯特滤波器，从而产生中间值，并且 接收机中的匹配滤波器（36和37）。 信道脉冲响应估计器（44'）将这些值与导出的符号值一起用作其更新过程的输入以维持模型。

公开(公告)号：US5432859A

公开(公告)日：1995-07-11

申请号：US47556

申请日：1993-02-23

申请人： Jin Yang ,  Andrew Sendyk

发明人： Jin Yang ,  Andrew Sendyk

IPC分类号： H04R3/00 ,  H04B15/00

CPC分类号： H04R3/00

摘要： A noise-suppression circuit (10) divides the signal from a microphone (12) into a plurality of frequency sub-bands by means of a noise-band divider (18) and a subtraction circuit (36). By means of gain circuits (32) and (34), it applies separate gains to the separate bands and then recombines them in a signal combiner (38) to generate an output signal in which the noise has been suppressed. Separate gains are applied only to the lower subbands in the voice spectrum. Accordingly, the noise-band divider (18) is required to compute spectral components for only those bands. By employing a sliding-discrete-Fourier-transform method, the noise-band divider (18) computes the spectral components on a sample-by-sample basis, and circuitry (50, 52) for determining the individual gains can therefore update them on a sample-by-sample basis, too.

摘要翻译： 噪声抑制电路（10）通过噪声带分频器（18）和减法电路（36）将来自麦克风（12）的信号分成多个频率子频带。 借助于增益电路（32）和（34），它向单独的频带施加单独的增益，然后将它们复合到信号组合器（38）中，以产生噪声被抑制的输出信号。 单独的增益仅应用于语音频谱中的较低子带。 因此，需要噪声带分频器（18）来计算仅这些频带的频谱分量。 通过采用滑动离散傅立叶变换方法，噪声带分频器（18）逐个采样地计算频谱分量，因此用于确定各个增益的电路（50,52）可以在 也是逐个样本的基础。