紫外光通信系统的噪声研究

Research on noise in ultraviolet communication systems

在UV(紫外光)通信系统中,噪声对信号会产生比较明显的干扰。为了提高系统的通信性能,文章对UV通信系统中的噪声进行了分析。设计了一个模块对噪声进行采样,并分析了PMT(光电倍增管)暗电流噪声、PCB(印制电路板)热噪声、EMI(电磁干扰)噪声以及电源引入的噪声等4种噪声的时域和频域特性,及其对系统性能的影响。为了克服模拟滤波性能不理想的缺点,在接收端采用FPGA(现场可编程门阵列)设计了一个数字滤波器来抑制噪声。实验结果表明,该数字滤波器对SNR(信噪比)有3～7dB的改善。

Noises in the Ultraviolet （UV） communication system bring about significant interference in signal transmission. In order to improve the system performance, this paper designs a module to sample the noises in the system, including Photomul-tiplier Tube （PMT）, dark current noise, PCB hot noise, Electromagnetic Interference （EMI） noise and noises induced by pow-er source and analyze their characteristics in time and frequency domains and their effects on the system performance. To over-come the disadvantages of analog filters, it develops a digital filter at the receiver end by using FPGA to suppress the noise. The experimental results show that this digital filter imoroves the Signal to Noise Ratio （SNR） bv 3-7 dB.