基于全相位陷波器解析设计的啸叫去除

为了快速且精准地抑制助听器中的啸叫效应，该文提出一种中心频率可以精确控制的全相位有限脉冲响应(FIR)陷波器解析设计。首先，为了获得较高的陷波精度，引入了整数部分m和小数部分λ来控制陷波的中心频率。然后，设计了一个偶对称的闭式解析式来计算陷波器系数。最后，为了保证输出信号的连续性和线性相位，进行数据延拓和截取操作。该陷波器具有线性传输特性，避免了非线性失真。为了检验陷波器的滤波性能，将其应用在助听器中去除啸叫。实验结果表明，该滤波器在啸叫频率下的衰减值可达–330 dB，信噪比达22 dB，输出波形质量好，算法复杂度低，鲁棒性高，具有一定的应用前景。

Howling Removal Based on Analytical Design of All-phase Notch Filter

In order to quickly and accurately suppress the howling effect in hearing aids, this paper presents an analytical design of all-phase Finite Impulse Response(FIR) notch filter with explicit controllable center frequency. Firstly, to obtain the higher accuracy, integer m and decimal λ are introduced to control the central frequency of the notch filter. Then, an even symmetric closed-form analytic formula is designed to complete the design of the notch filter, which shows that the proposed notch filter has linear transmission characteristics and avoids nonlinear distortion. Finally, data extension and interception are carried out to ensure the continuity and linear phase of the output signal. Herein, the proposed notch filter is inserted into hearing aid to suppress the howling for the sake of verifying its performances. The experimental results show that the attenuation value of the proposed filter at the howling frequency can reach –330 dB, and the SNR is 22 dB. Moreover, the proposed filter is of good output waveform quality, low algorithm complexity and high robustness, and it has a certain application prospect.