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1. 发明授权

US6088445A Adaptive filter system having mixed fixed point or floating point and block scale floating point operators 失效
标题翻译：自适应滤波器系统具有混合的固定点或浮点和块标度浮点运算符
公开(公告)号：US6088445A
公开(公告)日：2000-07-11
申请号：US904898
申请日：1997-08-01
申请人： Mandeep Chadha , Shawn Robert McCaslin , John Camagna , Nariankadu Datatreya Hemkumar
发明人： Mandeep Chadha , Shawn Robert McCaslin , John Camagna , Nariankadu Datatreya Hemkumar
IPC分类号： H03H17/02 , H03H17/06 , H03H21/00 , H04B3/23 , H04M9/00 , G06F17/10
CPC分类号： H03H17/0238 , H03H17/0227 , H03H21/0012
摘要： An adaptive filter is provided which has fixed point or floating point data stored in a data RAM (74) and block scale floating point coefficients stored in a coefficient RAM (84). The data and coefficients are utilized in a filter algorithm which utilizes a multiplier and an accumulator to provide a convolution result. Coefficients are updated by adding the multiplied result of the data RAM value and the error value to the old value of the coefficient. This is done for all the coefficient values in the coefficient RAM. The error value indicates the difference between the filter output and the sampled near-end signal that is the echo. These new coefficients are examined and if any have a value above or all have a value below a predetermined threshold, then the mantissas of all the coefficients are shifted and the exponent adjusted in the next filter cycle.
摘要翻译：提供了一种自适应滤波器，其具有存储在数据RAM（74）中的固定点或浮点数据以及存储在系数RAM（84）中的块比例浮点系数。数据和系数被用在利用乘法器和累加器来提供卷积结果的滤波器算法中。通过将数据RAM值的相乘结果和误差值相加到系数的旧值来更新系数。这是对系数RAM中的所有系数值进行的。误差值表示滤波器输出和作为回波的采样近端信号之间的差异。检查这些新系数，如果有的值高于或全部具有低于预定阈值的值，则所有系数的尾数被移位，并且在下一个滤波器周期中调整指数。

2. 发明授权

US5764753A Half-duplex controller 失效
标题翻译：半双工控制器
公开(公告)号：US5764753A
公开(公告)日：1998-06-09
申请号：US536054
申请日：1995-09-29
申请人： Shawn Robert McCaslin , Nariankadu Datatreya Hemkumar , Bheeshmar Redheendran
发明人： Shawn Robert McCaslin , Nariankadu Datatreya Hemkumar , Bheeshmar Redheendran
IPC分类号： H04B3/23 , H04M1/00
CPC分类号： H04B3/234
摘要： A double-talk detector for an echo canceller includes power estimators (60) and (62) which are utilized to measure the ERLE value in a calculator (64). This ERLE is stored in a register (70) when it is the largest value generated. This register (70) is updated whenever a new and better ERLE occurs. A fraction of the value in register (70) is utilized as an input to a comparator (88), and then compared to the current ERIE value. If the current ERLE differs from the SERLE in register (70) an inhibit signal is generated for blocking the updates of an adaptive filter (40). The value stored in the register (70) is periodically decremented to reduce the value thereof. This decrement operation is performed in response to detection of an utterance from the far-end. A half-Duplex operation is provided with two attentuators (352) and (354) to provide a switching operation and allow only one side access to the communication path. Speech, or the occurrence of an utterance is monitored at each end by comparing the raw input power at each end to a scaled up background noise power for that end. Different scaling factors for speech detection, or utterance detection, are provided, there being a high scaling factor and a low scaling factor. The side with the initially detected utterance will have access to the system and have the lowest scaling factor associated therewith, the other having the highest scaling factor associated therewith.
摘要翻译：用于回波消除器的双方通话检测器包括用于在计算器（64）中测量ERLE值的功率估计器（60）和（62）。当它是生成的最大值时，该ERLE存储在寄存器（70）中。每当发生新的和更好的ERLE时，该寄存器（70）被更新。将寄存器（70）中的值的一部分用作比较器（88）的输入，然后与当前ERIE值进行比较。如果当前的ERLE与寄存器（70）中的SERLE不同，则产生阻止自适应滤波器（40）的更新的禁止信号。存储在寄存器（70）中的值被周期性地递减，以减小它的值。响应于从远端发出的话语的检测来执行该递减操作。半双工操作提供有两个注意器（352）和（354）以提供切换操作，并且仅允许一侧访问通信路径。通过将每一端的原始输入功率与该目的的放大背景噪声功率进行比较，可以在每一端监视语音或话音的发生。提供用于语音检测或话语检测的不同缩放因子，存在高比例因子和低比例因子。具有初始检测到的话语的一侧将具有对系统的访问并且具有与其相关联的最低缩放因子，另一个具有与其相关联的最高缩放因子。

3. 发明授权

US5668794A Variable gain echo suppressor 失效
标题翻译：可变增益回波抑制器
公开(公告)号：US5668794A
公开(公告)日：1997-09-16
申请号：US552558
申请日：1995-11-03
申请人： Shawn Robert McCaslin , Nariankadu Datatreya Hemkumar
发明人： Shawn Robert McCaslin , Nariankadu Datatreya Hemkumar
IPC分类号： H04B3/23 , H04B3/20
CPC分类号： H04B3/234
摘要： A variable gain echo suppressor is provided that utilizes two variable attenuators (410) and (412) that are disposed in the receive and transmit paths, respectively, of a communication system. An echo suppressor (414) receives the input from the far end and transmits the output from the near end and controls the two attenuators to set a variable gain therein. The echo suppressor utilizes a normalized power level which is normalized with respect to the background noise at the respective end and then takes the ratio of this normalized power and the normalized power at the opposite end to define an associated power ratio. This power ratio value is utilized to determine the attenuation for the associated end. When the power ratio is high, this indicates that a stronger signal is being received from that end and a small amount of attenuation is associated in the transmit path from that end. When they aye equal, this will result in both systems having approximately the same attenuation, a mid-level attenuation. This is provided through a look up table (450) for the far end and a look up table (452) for the near end. Additionally, the signal power is derived from a peak detection IIR filter (420) and (428) which has the characteristics thereof changed as a function of the power ratio. This is achieved by changing the value of the pole in the IIR filter.
摘要翻译：提供了一种可变增益回波抑制器，其利用分别布置在通信系统的接收和发送路径中的两个可变衰减器（410）和（412）。回波抑制器（414）从远端接收输入，并从近端发送输出，并控制两个衰减器以在其中设置可变增益。回波抑制器利用归一化的功率电平，其相对于相应端的背景噪声被归一化，然后将该归一化功率与在相对端的归一化功率的比率定义为相关联的功率比。该功率比值用于确定相关端的衰减。当功率比高时，这指示从该端接收更强的信号，并且在该端的发送路径中少量的衰减被关联。当它们相等时，这将导致两个系统具有大致相同的衰减，即中间级衰减。这通过用于远端的查找表（450）和用于近端的查找表（452）来提供。此外，信号功率是根据功率比的函数变化的峰值检测IIR滤波器（420）和（428）导出的。这是通过改变IIR滤波器中极点的值来实现的。

4. 发明授权

US06894989B1 Separation circuit for an echo canceling system and method of operating the same 有权
标题翻译：用于回波消除系统的分离电路及其操作方法
公开(公告)号：US06894989B1
公开(公告)日：2005-05-17
申请号：US09650854
申请日：2000-08-29
申请人： Mandeep Singh Chadha , Shawn Robert McCaslin , Mile Milisavljevic
发明人： Mandeep Singh Chadha , Shawn Robert McCaslin , Mile Milisavljevic
IPC分类号： H04M1/76 , H04B3/23 , H04L1/00 , H04B3/20
CPC分类号： H04L1/0054 , H04B3/23 , H04L25/03993
摘要： A separation circuit, method of determining a residual level of an echo, and an echo canceling system, bit pump and transceiver employing the circuit and method. The echo canceling system employing the separation circuit is couplable between a transmit and receive path of the bit pump and generates an echo canceling signal. In one embodiment, the separation circuit includes a symbol determination circuit that accepts a receive signal, propagating along the receive path, substantially free of an echo and determines a symbol associated with the receive signal. The separation circuit also includes an estimator stage, coupled to the symbol determination circuit, that receives the symbol and provides an estimated receive signal. The separation circuit generates data representing a residual level of the echo as a function of the estimated receive signal and the echo canceling signal.
摘要翻译：分离电路，确定回波残余电平的方法以及回波消除系统，采用该电路和方法的位泵和收发器。使用分离电路的回波消除系统可以在位泵的发送和接收路径之间耦合，并产生回波消除信号。在一个实施例中，分离电路包括符号确定电路，其接收沿着接收路径传播的基本上没有回波的接收信号，并确定与接收信号相关联的符号。分离电路还包括耦合到符号确定电路的估计器级，其接收符号并提供估计的接收信号。分离电路产生表示作为估计的接收信号和回波消除信号的函数的回波的残余电平的数据。

5. 发明授权

US06983047B1 Echo canceling system for a bit pump and method of operating the same 失效
标题翻译：一种位泵的回波消除系统及其运行方法
公开(公告)号：US06983047B1
公开(公告)日：2006-01-03
申请号：US09650853
申请日：2000-08-29
申请人： Mandeep Singh Chadha , Shawn Robert McCaslin , Mile Milisavljevic
发明人： Mandeep Singh Chadha , Shawn Robert McCaslin , Mile Milisavljevic
IPC分类号： H04M9/08
CPC分类号： H04B3/23
摘要： An echo canceling system, method of attenuating echo, and a bit pump and transceiver employing the system and method. The echo canceling system is couplable between a transmit and receive path of the bit pump and receives and attenuates the echo in a receive signal propagating along the receive path. In one embodiment, the echo canceling system includes a slave echo canceling stage that employs a filter coefficient to attenuate the echo. The echo canceling system also includes a separation circuit, coupled to the slave echo canceling stage, that generates data representing a residual echo substantially exclusive of the receive signal. The echo canceling system still further includes a master echo canceling stage, coupled to the separation circuit, that receives the data and modifies the filter coefficient based thereon.
摘要翻译：回波消除系统，衰减回波的方法，以及采用该系统和方法的位泵和收发器。回波消除系统可在位泵的发送和接收路径之间耦合，并接收并衰减沿着接收路径传播的接收信号中的回波。在一个实施例中，回波消除系统包括使用滤波器系数衰减回波的从回声消除级。回波消除系统还包括耦合到从属回波消除级的分离电路，其生成表示基本上不包括接收信号的残余回波的数据。回波消除系统还包括耦合到分离电路的主回声消除级，其基于此接收数据并修改滤波器系数。

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