 　　产生长度为1000的标准正太分布的随机信号，画出时域波形及频谱；

 　　采用u=255的非均匀PCM编码，每符号为8bit，画输入-输出关系图；

 　　计算信号量化噪声比（SQNR）；

 　　信道误码率为10-3；

 　　解码，并画出u律反变换后的信号时域波形及频谱。

扩展要求：

 　　采用均匀PCM、量化级数可变、信道误码率可变。

-　have a standard length of 1000 is too random signal distribution, draw time-domain waveform and frequency spectrum　　u = 255 using the non-uniform PCM encoding, each symbol for 8bit, drawing input- output relationship diagram　　calculated quantization noise signal than (SQNR)　　channel bit error rate of 10-3　　decoder, and law to draw u the signal after the inverse transform time-domain waveform and frequency spectrum. Expansion of the requirements: 　uniform PCM, quantization level variable, a variable channel bit error rate.