使用matlab程序实现了由随机序列到码元电平、m序列直接扩频解扩、qpsk调制解调，射频调制解调一个完整的qpsk系统过程,Matlab program to use by the random sequence to the symbol level, m direct sequence spread spectrum despreading, qpsk modulation and demodulation, RF modulation and demodulation of the QP