本仿真程序对一串二进制信息进行QPSK调制，并画出其波形图和功率谱，在某种无线AWGN信道上进行传输，然后并在接收端进行解调，最后画出其误符号性能曲线-The simulation program for a string of binary information in QPSK modulation, and draw the waveforms and power spectrum, in some wireless AWGN channel for transmission, and t