用matlab记录一段基带语音信号，采样频率设为44.1kHz。产生一个高斯白噪声

随机过程，并将噪声叠加在语音信号上（相当于将语音信号通过一个高斯信道）。

（1） 设定不同的噪声信噪比，画出并比较高斯信道接收端的信号时域波形，播

放接收信号。

（2） 由于语音信号的范围通常在3kHz以内，在接收端加载一个低通滤波器，

截止频率为3kHz，画出并比较滤波前后的信号时域波形，并播放滤波后

的信号。-Matlab record with some baseband voice signal, the sampling frequency is set to 44.1kHz. Generating a Gaussian white noise

Random process, and the noise superimposed on the speech signal (corresponding to the speech signal through a Gaussian channel).

(1) set different noise SNR, draw time-domain waveform signal and compares the receiving end of a Gaussian channel, broadcast

Put the received signal.

(2) Because of the voice signal is usually less than 3kHz, is loaded at the receiving end of a low-pass filter,

Cutoff frequency of 3kHz, draw time-domain waveform signal and compare before and after filtering, the filtered and play

Signal.