基于CIC滤波器原理的音频信号快速重采样算法

A FAST RESAMPLING ALGORITHM OF AUDIO SIGNAL BASED ON THE PRINCIPLE OF CIC FILTER

针对现有音频信号重采样算法普遍具有的计算开销大的缺点,提出一种基于级联积分器与梳状(CIC)滤波器原理的音频信号快速重采样算法,应用于计算资源有限的嵌入式系统中。构造同时包含内插和抽取环节的三级CIC重采样滤波器,并根据其工作过程提出一种基本的音频信号重采样算法。推导由积分器寄存器值计算重采样值的公式,替代基本重采样算法中耗时的内插循环操作,从而得到音频信号快速重采样算法。该快速算法不需要存储滤波器系数,计算开销极小,在满足奈奎斯特采样定理的前提下可实现任意采样率转换,极大地提高了嵌入式音频重采样系统的性价比。

Aiming at the shortcoming that the existing audio signal resampling algorithm has great computational overhead,a fast resampling algorithm of audio signal based on the principle of Cascade Integrator and Comb(CIC) filter is proposed. We applied it to the embedded system with limited computing resources. We constructed a three-stage CIC resampling filter containing both interpolation and decimation links,and proposed a basic audio signal-resampling algorithm according to its working process. Then,the formula for calculating the resampling value from the integrator register value was deduced,which replaced the time-consuming interpolation loop operation in the basic resampling algorithm,and the fast resampling algorithm of the audio signal was obtained. The fast algorithm does not need the storage filter coefficient,and has very small calculation overhead. It can realize arbitrary sampling rate conversion under the premise of satisfying the Nyquist sampling theorem,and greatly improves the performance price ratio of the embedded audio resampling system.