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3~7 dB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 Photomultiplier Tube (PMT), dark current noise, PCB hot noise, Electromagnetic Interference (EMI) noise and noises induced by power source and analyze their characteristics in time and frequency domains and their effects on the system performance. To overcome 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 improves the Signal to Noise Ratio (SNR) by 3~7 dB.