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公开(公告)号：US5278900A
公开(公告)日：1994-01-11
申请号：US680485
申请日：1991-04-04
CPC分类号： H04B3/234
摘要： A digital echo canceller has a receive path (2) and a send path (3) and comprises combining apparatus (10) for forming a send output signal [r(k)] as the difference between the signal [z(k)] applied to the send input (SI) and a replica signal [e(t)] used for cancelling an additive echo signal [e(k)] at the send input (SI) that has developed in response to a receive input signal [x(k)] applied to the receive input (RI), which echo canceller at least includes transforming apparatus (13, 15) for transforming the receive input signal [x(k)] and the send output signal [r(k)]; transforming apparatus (14) for transforming the replica signal [e(k)]; a digital adaptive filter (9) which has a number of filter coefficients for generating the replica signal [e(t)] in response to the receive input signal [x(k)] and the send output signal [r(k)], adaptation apparatus (12) for determining for each block m, adaptation components [A(p;m)] for each of the filter coefficients [W(p;m)] in response to the receive input signal [x(k)] and the send output signal [r(k)]; controllable gate means (17) for selectively passing the adaptation components [A(p;m)] to the adaptive digital filter (9); control apparatus (25-28, 21-24, 16) for determining respective levels of the send output signal [r(k)] and the receive input signal [x(k)] and for generating a control signal for the gate apparatus (17) in response to the levels thus determined, which control signals depend in a predetermined manner on the difference between the levels concerned.
摘要翻译： 数字回声消除器具有接收路径（2）和发送路径（3），并且包括用于形成发送输出信号（r（k））的组合装置（10）作为施加的信号（z（k））之间的差 用于响应于接收输入信号而产生的发送输入（SI），用于消除加性回波信号（e（k））的发送输入（SI）和复制信号（e（t））（x（ k）），该回波消除器至少包括用于变换接收输入信号（x（k））和发送输出信号（r（k））的变换装置（13,15）; 变换装置（14），用于变换复制信号（e（k））; 响应于接收输入信号（x（k））和发送输出信号（r（k）），具有用于产生复制信号（e（t））的滤波器系数的数字自适应滤波器（9） 适应装置（12），用于响应于接收输入信号（x（k））为每个块m确定每个滤波器系数（W（p; m））的适应分量（A（p; m）），以及 发送输出信号（r（k））; 用于选择性地将自适应分量（A（p; m））传递到自适应数字滤波器（9）的可控门装置（17）; 控制装置（25-28,21-24,16），用于确定发送输出信号（r（k））和接收输入信号（x（k））的各个电平，并用于产生门装置的控制信号 17）响应于如此确定的电平，哪个控制信号以预定的方式取决于所涉及的电平之间的差异。
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公开(公告)号：US06424680B1
公开(公告)日：2002-07-23
申请号：US08576544
申请日：1995-12-21
IPC分类号： H04L2704
CPC分类号： H04H20/46 , H03M13/2732 , H04H20/72 , H04H40/27 , H04H2201/20 , H04L1/0043 , H04L1/0052 , H04L1/0071 , H04L27/2647
摘要： A digital signal is interleaved by delaying samples thereof by an integral number times a unit delay in accordance with a cyclically repeated delay pattern (AL91) . . . AL(M) Select lines (AL91) . . . AL(M)) of a memory (HAS) are cyclically activated (HAS) at a cycle rate equal to unit delay. During the activation of a select line, both data is written and read from the memory. The data written comprises a relevant bit of each sample to be delayed in an integral number of sample groups. Each sample group is associated with one delay pattern cycle. The data read (b(1,1,j)@a1 . . . b(1,M,j)@aM . . . b(k,1,j)@a1 . . . b(k,M,j)@aM) comprises a number of bits which is equal to the number of bits written. The bits are read in accordance with the delay pattern. Accordingly, the speed requirements imposed on the memory (MEM) are relatively lax.
摘要翻译： 通过根据循环重复的延迟模式（AL91）将其样本延迟整数倍的单位延迟来交织数字信号。 。 。 AL（M）选择行（AL91）。 。 。 AL（M））以等于单位延迟的周期速率循环地激活（HAS）。 在选择行的激活期间，两个数据都是从存储器写入和读取的。 写入的数据包括要在整数个样本组中延迟的每个样本的相关位。 每个样本组与一个延迟模式循环相关联。 数据读取（b（1,1，j）@ a1 ... b（1，M，j）@ aM ... b（k，1，j）@ a1 ... b（k，M，j ）@aM）包括等于写入的位数的多个位。 这些位根据延迟模式读取。 因此，对存储器（MEM）施加的速度要求相对较低。
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公开(公告)号：US5862189A
公开(公告)日：1999-01-19
申请号：US576545
申请日：1995-12-21
IPC分类号： H03M13/27 , H04H20/72 , H04H40/27 , H04H60/27 , H04J11/00 , H04L1/00 , H04L27/26 , H04L27/06
CPC分类号： H04H40/27 , H03M13/27 , H04L1/0052 , H04L1/0054 , H04L1/0071 , H04L27/2647 , H04H20/72 , H04H2201/20 , H04H60/27
摘要： In a digital audio broadcast receiver a digital audio transmission signal is supplied to a demodulator which provides demodulation samples. The demodulation samples are de-interleaved in a first section of a de-interleaving memory. After having been de-interleaved, demodulation samples are transferred to a second section of the de-interleaving memory. This transfer is effectuated in bursts via a relatively small buffer which stores the bursts. The second section of the de-interleaving memory effectively constitutes a relatively large buffer. De-interleaved demodulations samples are regularly read from the second section and supplied as a regular stream to a Viterbi decoder by means of a relatively small first-in first-out register.
摘要翻译： 在数字音频广播接收机中，将数字音频传输信号提供给提供解调样本的解调器。 在解交织存储器的第一部分中对解调样本进行解交织。 在解交织之后，将解调样本传送到解交织存储器的第二部分。 该传输通过存储脉冲串的相对较小的缓冲器以突发方式实现。 解交织存储器的第二部分有效地构成相对较大的缓冲器。 从第二部分定期读取解交织的解调样本，并通过较小的先进先出寄存器作为常规流提供给维特比解码器。
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公开(公告)号：US5390250A
公开(公告)日：1995-02-14
申请号：US810776
申请日：1991-12-17
CPC分类号： H04M9/082
摘要： An echo canceller for use in send/receive apparatus includes a frequency-domain adaptive filter which provides filter parameters to a time-domain programmable filter. The programmable filter produces a signal y(k) which is an estimate of the echo signal produced by acoustic coupling between a loudspeaker in the received path and a microphone in the send path. By subtracting this estimate from the signal produced in the send path, an output signal r(k) is obtained from the send path which is essentially free of echoes. An accurate estimate of the echo signal cannot be obtained if a send signal is present at the input of the send path. Therefore, detecting means in the adaptive filter detects whether such a send signal is present and in that case blocks the transfer of filter parameters from the adaptive filter to the programmable filter. Erroneous modification of the estimated echo signal is thereby avoided. Detection of the presence of a send signal is based on whether the ratio of the power of the signal z(k) in the send path to the power of an output signal of the adaptive filter exceeds a specific threshold.
摘要翻译： 用于发送/接收设备的回波消除器包括频域自适应滤波器，其向时域可编程滤波器提供滤波器参数。 可编程滤波器产生信号y（k），其是通过接收路径中的扬声器与发送路径中的麦克风之间的声耦合产生的回波信号的估计。 通过从在发送路径中产生的信号中减去该估计，从基本上没有回波的发送路径获得输出信号r（k）。 如果发送信号存在于发送路径的输入端，则无法获得回波信号的精确估计。 因此，自适应滤波器中的检测装置检测这样的发送信号是否存在，并且在这种情况下阻止滤波器参数从自适应滤波器到可编程滤波器的传送。 从而避免了估计的回波信号的错误修改。 发送信号的存在的检测基于发送路径中的信号z（k）的功率与自适应滤波器的输出信号的功率的比率是否超过特定阈值。
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5.发明授权Receiver de-interleaving means and a method for a reduced time de-interleaving memory 失效接收机解交织装置和减少时间解交织存储器的方法
公开(公告)号：US6075828A
公开(公告)日：2000-06-13
申请号：US961966
申请日：1997-10-31
CPC分类号： H03M13/2789 , H04H40/18 , H04H2201/20
摘要： A DAB receiver in which a reduced time de-interleaving memory for storing metrics is used, but which still allows processing of DAB services which normally would exceed the storage capacity of the memory. This is achieved by varying the length of a stored metric, depending upon the storage capacity required, by varying the number of stored reliability bits in a metric. In this way, a trade-off can be made between storage capacity and processing quality.
摘要翻译： 一种DAB接收机，其中使用用于存储度量的减少时间解交织存储器，但是仍然允许处理通常将超过存储器的存储容量的DAB服务。 这通过改变存储的度量的长度来实现，取决于所需的存储容量，通过改变度量中存储的可靠性位的数量。 以这种方式，可以在存储容量和处理质量之间进行权衡。
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公开(公告)号：US4903247A
公开(公告)日：1990-02-20
申请号：US210268
申请日：1988-06-23
CPC分类号： H04B3/237 , H04M9/082 , H04B3/234 , H04B3/238 , Y10S367/901
摘要： A digital echo canceller [1] with a good protection against double-talk comprises a first filter [9] for the echo cancellation proper, a second adaptive filter [11] for making continuously adapted filter coefficients available to the first filter [9] and gate means [15] which will only apply the adapted filter coefficients to the first filter [9] if certain conditions are satisfied. In the echo canceller [1] a specific filter combination is used, in which the first filter [9] is a time-domain programmable filter (TDPF) and the second filter [11] is a frequency-domain block-adaptive (FDAF), and further means [20,20(1)] are provided that are arranged in cascade with the gate means [15] for transforming the frequency-domain filter coefficients [W(p;m)] of the FDAF [11] into time-domain filter coefficients [w(i;m)] for the TDPF [9]. These measures result in the advantages of a negligible delay in the echo cancellation by the TDPF [9], and of the possibility to improve in a simple manner the convergence behavior of the FDAF [11] and considerably reduce its computational complexity.
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