说明：  伪随机码或称PN码，是扩频通信中不可缺少的一种序列。扩频通信，简单的说来就是通过一组相关性很强的伪随机序列，使原有的信号按照伪随机序列的特性出现。从波形上看，原有信号完全淹没于随机的噪声中，达到隐藏信号和抗干扰的目的。接受方只要有相同的伪随机序列，就可以通过伪随机序列很强的相关性将信号还原出来。而m序列，是扩频系统中最长用的伪随机序列。下面的代码就是基于matlab的生成m序列的代码，通过改变初始多项式的值，就可以生成不同阶数的m序列。
(Pseudo-random code or PN code, spread spectrum communication is indispensable to a sequence. Spread spectrum communication, a simple to say that the adoption of a group of highly related to pseudo-random sequence, so that the original signal in accordance with the characteristics of pseudo-random sequence there. From the wave point of view, the original signal completely submerged in the random noise to hide the purpose of signal and interference. As long as the recipient has the same pseudo-random sequence, the pseudo-random sequence can be a strong correlation to restore the signal out. And m sequence spread spectrum system is the longest of the pseudo-random sequence used. The following code is generated based on m sequences of matlab code, by changing the value of the initial polynomial, we can generate a different order of the m sequence.)