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with fir and iir filters echokompensator for compensation of echoes with a long ausschwingen.

机译:带有冷杉滤光片和IIR滤光片的echokompensator用于补偿较长的ausschwingen的回波。

摘要

An echo canceller comprises a finite impulse response filter (6) connected to the incoming port of a hybrid (1), and a tail canceller (7) which includes an infinite impulse response filter (24; 40) having a multiplier (14; 33) for recursively multiplying an output digital symbol from the tapped-delay line (8) of the FIR filter with an attenuation coefficient R. A digital symbol from the IIR filter or one from the tapped-delay line (8) is multiplied with a tap-weight coefficient Ci and summed with the outputs of tap-weight multipliers of the FIR filter to produce a replica of an echo symbol, which is subtracted from a digital symbol yn from the outgoing port of the hybrid (1), producing a residual echo symbol en. The coefficient Ci is derived from correlation between residual echo en and a symbol from the tapped-delay line. In one embodiment, symbol from the tapped-delay line is further delayed (17) for a unit interval on the one hand, and multiplied (18) with coefficient R on the other, the difference between them being detected (19) and multiplied (20) with a coefficient K, which is either sgn(Ci) or 1/Ci, to generate a multiplied difference. Correlation is detected (22) between the difference and residual echo en to derive the coefficient R. In a second embodiment, symbol from the tapped-delay line is further delayed (36) for a unit interval and multiplied (37) with K to produce a delayed-multiplied symbol. Correlation is detected (35) between it and residual echo en to derive the coefficient R.
机译:回声消除器包括连接到混合器(1)的输入端口的有限脉冲响应滤波器(6)和尾部消除器(7),尾部消除器(7)包括具有乘法器(14; 33)的无限脉冲响应滤波器(24; 40)。 )递归地将FIR滤波器的抽头延迟线(8)的输出数字符号与衰减系数R相乘。IIR滤波器的数字符号或抽头延迟线(8)的数字符号与抽头相乘。加权系数Ci并与FIR滤波器的抽头加权乘法器的输出相加,以产生回声符号的副本,然后从混合器(1)的输出端口的数字符号yn中减去回声符号的副本,从而产生残留回声符号en。系数Ci是从残留回波en和抽头延迟线的符号之间的相关性得出的。在一个实施例中,来自抽头延迟线的符号一方面进一步延迟(17)一个单位间隔,另一方面又与系数R相乘(18),它们之间的差被检测(19)并相乘( 20)的系数K为sgn(Ci)或1 / Ci,以产生相乘差。在差和残余回声en之间检测到相关性(22)以得出系数R。在第二实施例中,来自抽头延迟线的符号被进一步延迟(36)一个单位间隔,并且与K相乘(37)以产生延迟乘法符号。检测到它与残余回声en之间的相关性(35),以得出系数R。

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