说明：  基于DSP数字滤波，一个实际的应用系统中，总存在各种干扰。数字滤波器在语音信号处理、信号频谱估计、信号去噪、无线通信中的数字变频以及图像信号等各种信号处理中都有广泛的应用，数字滤波器也是使用最为广泛的信号处理算法之一。
(Based on DSP digital filtering, there are always various interferences in a practical application system. Digital filter is widely used in speech signal processing, signal spectrum estimation, signal denoising, digital frequency conversion in wireless communication, image signal and other signal processing. Digital filter is also one of the most widely used signal processing algorithms.)