CATV宽带网回传噪声分析与回传设计

众所周知,HFC有线电视网络的上行(回传)噪声,由于树枝型结构电缆分配系统的汇集,形成所谓的"漏斗"效应,使回传噪声累积到前端,严重恶化上行信道的信噪比.因此,如何降低回传噪声干扰,提高上行信道的频谱利用率,一直是确保交互系统上下行传输特性的关键问题.同时,宽带业务的上行通道运行没有像下行通道那样受人注意,上行通道存在的问题还没有完全被暴露并解决,上行通道的设计方案迄今为止还没有完全成形.本文在讨论噪声的同时,兼顾了回传系统的设计.

浅议光链路传输部分的回传设计

本文通过介绍噪声功率比(NPR)、反向激光器的"动态范围"、节点回传增益三个概念,详细说明了怎样利用上述概念搞好光链路传输部分的回传设计,保证回传信号稳定、可靠。

Soft sensor design for hydrodesulfurization process using support vector regression based on WT and PCA

A novel method for developing a reliable data driven soft sensor to improve the prediction accuracy of sulfur content in hydrodesulfurization(HDS) process was proposed. Therefore, an integrated approach using support vector regression(SVR) based on wavelet transform(WT) and principal component analysis(PCA) was used. Experimental data from the HDS setup were employed to validate the proposed model. The results reveal that the integrated WT-PCA with SVR model was able to increase the prediction accuracy of SVR model. Implementation of the proposed model delivers the best satisfactory predicting performance(EAARE=0.058 and R2=0.97) in comparison with SVR. The obtained results indicate that the proposed model is more reliable and more precise than the multiple linear regression(MLR), SVR and PCA-SVR.