公开(公告)号：US20040218755A1

公开(公告)日：2004-11-04

申请号：US10724043

申请日：2003-12-01

Applicant: Tandberg Telecom AS

Inventor： Trygve Frederik Marton ,  Ingvar Flaten Aarnes

IPC: H04M009/08

CPC classification number: H04M9/082

Abstract: An echo canceller processing echo, noise and near end talk in a narrower, but still intelligible, frequency band for reducing required processing power and complexity. In a preferred embodiment of the present invention, an input audio signal of captured sound in an audio communication system is decimated and then divided into a number of sub bands by an analyze filter. Each sub band is processed as in background audio echo cancelling by subtracting the signal with an echo estimate from a model of the acoustic signal in the respective sub band, except from that the signal is also bypassed, adjusted by a filter and subtracted from the processed signal. The resulting signals are then recombined by a synthesize filter and interpolated to the original sampling rate and bandwidth. Finally, the output from the synthesize filter is added to the input audio signal, which has been delayed and adjusted by a filter. The filters are controlled by a control algorithm detecting the presence of near end sound, far end sound and noise, so that the filters, and consequently the high pass filter of the echo canceller, only pass high frequency (above low pass frequencies) when only near end sound is detected.

Abstract translation: 回波消除器在较窄但仍然可理解的频带中处理回波，噪声和近端通话，以减少所需的处理能力和复杂性。 在本发明的优选实施例中，音频通信系统中的捕获声音的输入音频信号被抽取，然后由分析滤波器分成多个子频带。 通过从相应子带中的声学信号的模型中减去具有回波估计的信号来处理每个子带，除了信号被旁路之外，由滤波器调整并从处理的信号中减去 信号。 然后，所得到的信号由合成滤波器重新组合，并被内插到原始采样速率和带宽。 最后，将合成滤波器的输出添加到输入音频信号中，输入音频信号被滤波器延迟和调整。 滤波器由检测近端声音，远端声音和噪声的存在的控制算法控制，使得滤波器以及因此的回波消除器的高通滤波器仅在仅仅通过高频（高于低通频率）时才通过 检测到近端声音。