中文说明：
摘要：本文主要介绍了软件系统视图中π/4-DQPSK系统的调制和解调。此外，本文还分析了π/4-DQPSK系统的动态和静态行为，以及在高斯信道条件下的抗噪声性能。比较了π/4-DQPSK和QPSK在相同信道下的特殊抗噪性能。模拟结果显示π/4-DQPSKI的频谱扩展在QPSK系统周围。关键词：π/4-DQPSK；系统视图；计算机辅助设计（CAD）；Matlab
English Description：
Abstract: This paper mainly introduces the modulation and demodulation of π / 4-dqpsk system in the view of software system. In addition, this paper also analyzes the dynamic and static behavior of π / 4-dqpsk system and its anti noise performance under Gaussian channel. The special anti noise performance of π / 4-dqpsk and QPSK in the same channel is compared. The simulation results show that the spectrum spread of π / 4-dqpski is around the QPSK system. Keywords: π / 4-dqpsk; System view; Computer aided design (CAD); Matlab