Abstract: Code Division Multiple Access (CDMA) onboard system is an important part of Euroloop. In order to be compatible with European ring onboard system, it is necessary to add CDMA RF receiving and processing channels in the receiving and processing part. This paper studies the feasibility of RF signal processing channels, analyzes and studies from the aspects of high-power filters, low-noise amplifiers and differential conversion circuits, studies the characteristics and key technologies of the onboard radio frequency of Euroloop, and proposes the feasibility of CDMA onboard radio frequency system on the basis of modeling simulation and engineering realization verification of the filter, design analysis and index analysis of the low-noise amplifier and simulation and optimization of the differential conversion matching circuit.

Key words: radio frequency, high power, bandpass filtering, low noise amplification, power distribution, differential conversion

摘要： 码分多址（CDMA)车载系统是欧洲环线的重要组成部分，为兼容欧洲环线车载系统，需要在接收处理部分增加CDMA射频接收和处理通道。研究射频信号处理通道的可实现性，从高功率滤波器，低噪声放大器和差分转换电路方面进行分析研究，研究欧洲环线的车载射频特点和关键技术，在对滤波器进行建模仿真和工程实现验证，对低噪声放大器进行设计分析和指标分析，对差分转换匹配电路进行仿真优化的基础上，提出CDMA车载射频系统的可实现性。

关键词: 射频, 高功率, 带通滤波, 低噪声放大, 功率分配, 差分转换