说明：  数字通信中的QPSK调制解调模型，该模型包含完整的QPSK系统，含调制、脉冲成型、解调、判决等，对学习QPSK的开发人员有较大帮助。
(QPSK modulation and demodulation digital communication model, the model contains a complete QPSK system, including modulation, pulse shaping, demodulation, judgment, etc., help learning QPSK developers.)