一种自动等响度数字混音算法

在电视会议系统中，为获得接近真实的会议交流氛围，混音技术不可或缺。本文利用语音信号的响度特性，提出一种自动等响度数字混音算法。该算法首先利用信号平均功率和短时自相关函数进行语音活动检测(VAD)，判断参与混音的每路信号中是否含有语音信号。然后，利用时变滤波器进行滤波处理，抑制混音过程中引入的噪声。最后，利用语音信号响度计算各路信号的权重，使各路语音的平均响度保持一致。仿真实验结果表明，本文的混音算法可使各路信号的平均响度基本相同，并具有良好的语音质量。 

A Digital Audio Mixing Algorithm with Equal-Loudness

Audio mixing is indispensable to achieve the sense of reality in video conference systems. In this paper, a digital audio mixing algorithm with equal-loudness is proposed. Voice activity detection(VAD) is first performed by the average power and short-term autocorrelation sequence of signal. Then, the noise caused by audio mixing directly is filtered by the time-varying filter, where the passband variation of the filter depends on the result of voice activity detection. Finally, to achieve the effect of equal-loudness, the weight of each channel signal in audio mixing is calculated with the average loudness of voice. Simulation results show that the proposed algorithm can make the average loudness of each channel signal close to the same, which can effectively decrease the distortion of small-signal.