一个仿真数字带通QPSK调制系统的误码率的matlab程序。无论是仿真带通系统还是基带通信系统，通信系统模型的误码率的计算过程主要由设置相关参数、创建信号、即信源编码、调制、对调制信号添加高斯噪声、解调、计算系统的误码率等步骤组成。这个例子详细介绍如何利用matlab通信工具箱中提供的函数实现系统的误码率的仿真。-BER simulation of a digital bandpass QPSK modulation system matlab program. The simulation system either bandpass or baseband communication system, a communication error rate calculation process system model parameters set primarily by creating a signal, i.e., the source coding, modulation, Gaussian noise is added to the modulated signal, a demodulator, a computing system BER and other steps. This example describes in detail how to use matlab communication toolbox provides functions to achieve BER simulation system.