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    Adaptive discrete-time transversal filter
    3.
    发明公开
    Adaptive discrete-time transversal filter 失效
    适应性Zeitdiskretes Transversalfilter。

    公开(公告)号：EP0398441A1

    公开(公告)日：1990-11-22

    申请号：EP90201238.4

    申请日：1990-05-16

    申请人： Philips Electronics N.V.

    发明人： Sommen, Petrus Christianus Wilhelmus ,  Van Valburg, Christinus Johannes

    IPC分类号： H03H21/00 ,  H04B3/23

    CPC分类号： H03H21/0012 ,  H04B3/23 ,  H04B3/238

    摘要： Adaptive discrete-time filters, as used, for example, in echo cancellers, comprise a control circuit for controlling the coefficients for adjusting the discrete-time transversal filter. A prior art manner of adjustment is the LMS algorithm. This algorithm is relatively simple because few computations are necessary but they may lead to poor convergence results with autocorrelated input signals. Further, the OP algorithm is known which leads to good convergence results with auto-correlated input signals but which also requires a substantial amount of computation. According to the invention an algorithm is provided for input signals, more specifically speech signals, which may be modelled with an autoregressive process of the order of p, which algorithm requires the same amount of computation as the LMS algorithm but leads to the same or better convergence results for this type of signals than the OP algorithm.

    摘要翻译： 如在回波消除器中使用的自适应离散时间滤波器包括用于控制用于调整离散时间横向滤波器的系数的控制电路。 现有技术的调整方式是LMS算法。 该算法相对简单，因为很少的计算是必要的，但是它们可能导致与自相关输入信号的收敛结果较差。 此外，OP算法是已知的，其导致与自动相关输入信号的良好收敛结果，但是还需要大量的计算。 根据本发明，提供了一种用于输入信号，更具体地语音信号的算法，其可以用p阶的自回归过程来建模，该算法需要与LMS算法相同的计算量，但是导致相同或更好 这种类型的信号的收敛结果比OP算法。

    Frequency-domain block-adaptive digital filter
    4.
    发明公开
    Frequency-domain block-adaptive digital filter 失效
    Blockadaptives，digitales Filter im Frequenzgebiet。

    公开(公告)号：EP0250048A1

    公开(公告)日：1987-12-23

    申请号：EP87201133.3

    申请日：1987-06-16

    申请人： Philips Electronics N.V.

    发明人： Sommen, Petrus Christianus Wilhelmus ,  Claasen, Theodoor Antonius Carel Maria ,  Van Gerwen, Petrus Josephus ,  Kotmans, Hendrik Jan

    IPC分类号： H03H21/00

    CPC分类号： H03H21/00 ,  H03H21/0027

    摘要： A frequency-domain block-adaptive digital filter (FDAF) having a finite impulse response of length N for filtering a time-domain input signal in accordance with the overlap-save method includes window means (11) for obtaining modifications (B(p;m)) of the 2N frequency-­domain weighting factors (W(p;m)) from correlation pro­ducts (A(p;m)). A known FDAF of this type contains five 2N-points FFT's, two of which are used in the window means (11). By utilizing a special time-domain window function which can be implemented very efficiently in the window means (11) with the aid of a frequency-domain convolution, a FDAF of this type containing only three 2N-point FFT's is obtained whose convergence properties are comparable to those of the known FDAF containing five 2N-point FFT's.

    摘要翻译： 具有根据重叠保存方法对时域输入信号进行滤波的长度为N的有限脉冲响应的频域块自适应数字滤波器（FDAF）包括用于获得修改的窗口装置（11）（B（p; （A（p; m））的2N个频域加权因子（W（p; m）））。 这种类型的FDAF包含五个2N点FFT，其中两个用于窗口（11）。 通过利用可以在频域卷积的窗口装置（11）中非常有效地实现的特殊时域窗口函数，获得这样的仅包含三个2N点FFT的类型的FDAF，其收敛特性为 与已知的含有5个2N点FFT的FDAF的相似。