sheji

代码说明：

  先对语音信号进行采集、播放，分析其频谱，对该信号源添加噪声，再播放音频并分析频谱，然后分别通过IIR低通、带通滤波器和FIR低通、带通滤波器，分别播放音频和得到滤波后的频谱。(Firstly， voice signal acquisition, play, analyze its spectrum to add noise to the signal source, and then play the audio spectrum analysis, and then were by IIR low-pass, band-pass filter and FIR low-pass, band-pass filters, respectively, play audio and get the spectrum after filtering.)