强背景下混响时间的非线性滤波M序列相关测量

本文提出采用非线性滤波抑制在强背景噪声环境中用Ｍ－序列相关法得到的房间脉冲响应中的残余噪声影响，以扩大混响衰减曲线的动态范围，从而达到能够在强背景噪声环境下准确测量混响时间的目的。首先讨论了影响Ｍ序列相关法测量混响时间的几个因素。其次，采用非线性滤波进一步抑制背景噪声的影响。结果表明，非线性滤波的效果相当显著。本文还在非白噪声背景条件下用该法进行强背景下的混响时间测量，结果与传统测量结果符合得很好

Method of measuring reverberation time in strong noise environment using nonlinear filtering of the M-sequence correlation

To enhance the dynamic range of decay curves and obtain accurate reverber-ation time under the condition of strong background noise, nonlinear filtering of impulseresponse obtained by M-sequence correlation technique is presented in the paper. First,several factors affecting the measurement by M-sequence are discussed. Second, nonlinearfiltering is applied to improve immunity of M-sequence to background noise. Researchshows that nonlinear filters work very efficiently without the need to cut off impulse re-sponse data. We also make similar measurements under the condition of non-white noisebackground. Results are in good agreement with those of conventional measurementwhen S/N is above 40dB.