基于Simulink的通信系统眼图测试仿真

摘要

文中基于Simulink设计了通信系统眼图测试系统,分析了眼图测试在通信系统中的应用,从滤波、调制、信道噪声3个方面研究了如何通过眼图测试分析信号质量.噪声引起信号幅度畸变,过零点失真,加大误码率,且发送信号的比特率越高,噪声对信号的影响越明显,因此噪声限制了信号的传输速率.调制和滤波能够一定程度抑制噪声,改善系统性能.最后,本文提出了一种在任意波形发生器产生的串行信号添加高斯噪声的方法,用示波器测试合成信号的眼图,验证了Simulink的仿真中噪声对信号的影响结果.%This paper discusses the importance of eye diagram test in communication system. The eye diagram is a useful tool for the qualitative analysis of signal used in digital transmission. Firstly , a digital transmission system for eye diagram measurement is designed in the Simulink platform. Then , we test eye diagram under different conditions by changing the roll off factor of filter , modulation mode or channel noise and discuss how to analyze the signal quality through eye diagram. The simulation results show that the noise induces signal amplitude distortion and zero crossing distortion , increases the bit error rate. The higher the bit rate of the transmitted signal , the more obvious the effect of noise on the signal, so the noise limits the transmission rate of the signal. Filtering and modulation can suppress the influence of the noise to some extent. Finally , a new method of adding Gauss noise to the serial signal is presented. The eye diagram of the composite signal measured by the oscilloscope verifies the effect of noise on the signal as the simulation results show.