巴特沃斯带通数字IIR滤波器对加了高斯随机噪声和正弦噪声的语音信号进行滤波，并绘制了两滤波器滤波后的语音信号时域图和频谱图。-Butterworth band-pass digital IIR filter added Gaussian random noise and sinusoidal noise of the speech signal is filtered, and draw a diagram of two filter the filtered speech signal tim