说明：  1)生成2KHz和8KHz的混合信号，使该信号通过上述滤波器，观察滤波前后的波形变化和频谱分布情况。 2) 在改信号中加入高斯白噪声，观察滤波前后的波形变化和频谱分布情况3) 将上述滤波器改为中心频率为100KHz的带通滤波器，信号源为带外的90KHz和带内的100KHz的混合正弦信号，。 4) 用M文件实现上述低通滤波器。
(1) 2KHz and 8KHz to generate the mixed-signal, so that the signal through the above-mentioned filter, filter before and after observation of the waveform and spectrum distribution of the changes. 2) add to the signal in white Gaussian noise was observed before and after filtering and spectral waveform changes in the distribution of 3) will be replaced by the above-mentioned filter center frequency of 100KHz band pass filter, the signal source for the band and the band of 90KHz 100KHz Sine of the mixed signals. 4) achieve the above-mentioned documents with M low-pass filter.)