说明：  QPSK的MATLAB实现包括发送数据、QPSK比特映射、成型滤波、载波调制、载波解调、收成型匹配、IQ抽样判决、接收比特数据恢复8个模块
(The MATLAB implementation of QPSK includes eight modules: sending data, QPSK bit mapping, shaping filtering, carrier modulation, carrier demodulation, shaping matching, IQ sampling decision and receiving bit data recovery.)