The adaptive algorithm used for echo cancellation(EC) system needs to provide 1) low misadjustment and 2) high convergence rate. The affine projection algorithm(APA) is a better alternative than normalized least mean ...The adaptive algorithm used for echo cancellation(EC) system needs to provide 1) low misadjustment and 2) high convergence rate. The affine projection algorithm(APA) is a better alternative than normalized least mean square(NLMS) algorithm in EC applications where the input signal is highly correlated. Since the APA with a constant step-size has to make compromise between the performance criteria 1) and 2), a variable step-size APA(VSS-APA) provides a more reliable solution. A nonparametric VSS-APA(NPVSS-APA) is proposed by recovering the background noise within the error signal instead of cancelling the a posteriori errors. The most problematic term of its variable step-size formula is the value of background noise power(BNP). The power difference between the desired signal and output signal, which equals the power of error signal statistically, has been considered the BNP estimate in a rough manner. Considering that the error signal consists of background noise and misalignment noise, a precise BNP estimate is achieved by multiplying the rough estimate with a corrective factor. After the analysis on the power ratio of misalignment noise to background noise of APA, the corrective factor is formulated depending on the projection order and the latest value of variable step-size. The new algorithm which does not require any a priori knowledge of EC environment has the advantage of easier controllability in practical application. The simulation results in the EC context indicate the accuracy of the proposed BNP estimate and the more effective behavior of the proposed algorithm compared with other versions of APA class.展开更多
自适应滤波是语音增强算法中的常用技术,而算法复杂度与收敛速度是设计各种自适应算法需要首要考虑的问题.本文提出一种用于片上的语音增强自适应滤波新算法.该算法分两步实现,首先,利用一阶微分麦克风阵列,获得噪声的实时估计;其次,对...自适应滤波是语音增强算法中的常用技术,而算法复杂度与收敛速度是设计各种自适应算法需要首要考虑的问题.本文提出一种用于片上的语音增强自适应滤波新算法.该算法分两步实现,首先,利用一阶微分麦克风阵列,获得噪声的实时估计;其次,对传统的仿射投影算法(Affine projection algorithm,APA)加以改进,得到计算误差向量的快速算法,并根据估计误差动态调整搜索步长以及仿射投影维数,对带噪语音进行自适应滤波消噪.在TMS320VC5509 DSP芯片上实现该算法.实验表明,算法的自适应滤波过程具有接近递推最小二乘算法(Recursive least squares,RLS)的快速收敛速度,以及类似最小均方误差算法(Least mean squares,LMS)的低算法复杂度.展开更多
在传统的LMS(Least Mean Square)算法中,固定步长的选取影响收敛速度与稳态误差,而且两者不可兼得。因此,为在相应的领域内合理使用此类算法,针对这个问题在对多种自适应滤波LMS类算法进行原理分析后,得出此类算法在不同领域的特点,对...在传统的LMS(Least Mean Square)算法中,固定步长的选取影响收敛速度与稳态误差,而且两者不可兼得。因此,为在相应的领域内合理使用此类算法,针对这个问题在对多种自适应滤波LMS类算法进行原理分析后,得出此类算法在不同领域的特点,对今后不同人群的合理使用提供了良好条件。展开更多
文摘The adaptive algorithm used for echo cancellation(EC) system needs to provide 1) low misadjustment and 2) high convergence rate. The affine projection algorithm(APA) is a better alternative than normalized least mean square(NLMS) algorithm in EC applications where the input signal is highly correlated. Since the APA with a constant step-size has to make compromise between the performance criteria 1) and 2), a variable step-size APA(VSS-APA) provides a more reliable solution. A nonparametric VSS-APA(NPVSS-APA) is proposed by recovering the background noise within the error signal instead of cancelling the a posteriori errors. The most problematic term of its variable step-size formula is the value of background noise power(BNP). The power difference between the desired signal and output signal, which equals the power of error signal statistically, has been considered the BNP estimate in a rough manner. Considering that the error signal consists of background noise and misalignment noise, a precise BNP estimate is achieved by multiplying the rough estimate with a corrective factor. After the analysis on the power ratio of misalignment noise to background noise of APA, the corrective factor is formulated depending on the projection order and the latest value of variable step-size. The new algorithm which does not require any a priori knowledge of EC environment has the advantage of easier controllability in practical application. The simulation results in the EC context indicate the accuracy of the proposed BNP estimate and the more effective behavior of the proposed algorithm compared with other versions of APA class.
文摘自适应滤波是语音增强算法中的常用技术,而算法复杂度与收敛速度是设计各种自适应算法需要首要考虑的问题.本文提出一种用于片上的语音增强自适应滤波新算法.该算法分两步实现,首先,利用一阶微分麦克风阵列,获得噪声的实时估计;其次,对传统的仿射投影算法(Affine projection algorithm,APA)加以改进,得到计算误差向量的快速算法,并根据估计误差动态调整搜索步长以及仿射投影维数,对带噪语音进行自适应滤波消噪.在TMS320VC5509 DSP芯片上实现该算法.实验表明,算法的自适应滤波过程具有接近递推最小二乘算法(Recursive least squares,RLS)的快速收敛速度,以及类似最小均方误差算法(Least mean squares,LMS)的低算法复杂度.
