pi/4-qdpsk调制解调程序，能有效地进行差分解调和鉴频器解调，在一些不易提取载波的场合很有用。因此，利用仿真来研究系统是必要的。-pi/4-qdpsk modulation and demodulation process, can effectively reconcile the difference solution frequency discriminator demodulation, carrier extraction in a number of difficult situations is useful. Therefore, the use of simulation to study the system is necessary.