【作者】 鄢凯；

【导师】 黄秋元；

【作者基本信息】 武汉理工大学 ， 通信与信息系统， 2007， 硕士

【摘要】 随着WCDMA在全球范围内的铺开，其网络覆盖问题已经成为运营商不容忽视的一个问题。光纤直放站在GSM、CDMA和PHS系统中得到了广泛的应用，较好的解决以上通信网络的覆盖问题。因此，毫无疑问光纤直放站在WCDMA系统中会起到重要的作用。而射频光模块是光纤直放站的核心组成部分，它的工作性能直接影响网络覆盖的质量。本论文的研究目的就是设计一种WCDMA射频光模块，以满足WCDMA光纤直放站的设计需求，实现通信网络的覆盖。本文在深入分析了GSM、CDMA射频光模块的基础上，阐述了RF信号在光纤链路中应用的工作原理，从而提出了WCDMA射频光模块的解决方案并详细介绍了关键电路的实现原理及方式。首先，提出了使用PIN二极管构成的π型压控衰减器。该衰减器的优点是成本低，动态范围大，线性好等。其次，讨论了耦合微带线带通滤波器的设计理论，设计实现了一种之字形微带滤波器用来抑止模块的杂散发射，可以节约PCB空间提高产品性能的一致性。然后，在数传控制模块的输入和输出端加入了滤波器，使用1片FSK芯片完成了原来2片芯片才能实现的功能，大大节约了成本的同时提高了模块的集成度。最后，从系统角度分析了射频光模块的电磁兼容问题，设计了模块的腔体，解决了模块的电磁兼容问题。本文在介绍了射频光模块的各组成部分设计原理和全部硬件实现的同时，使用仿真软件ADS(Advanced Designing System)和HFSS(High FrequencyStructure Simulator)进行了设计仿真，极大的简化了电路的设计过程。通过仿真所设计的模块具有独特的双腔结构和可插拔的数传控制模块，实现了模块的模块化设计和灵活配置的改造能力。该WCDMA射频光模块已参加了直放站厂家的现场测试，各项指标都满足WCDMA的入网标准，取得了较满意的结果。更多还原

【Abstract】 As the construction of WCDMA network in the world, the network coverage becomes an inevitable issue for operators. Fiber optic repeater is widely applied in GSM, CDMA and PHS communication systems, which resolves the coverage problem well. Therefore the fiber optic repeater will play an important role in WCDMA system. As the key part of the repeater, the quality of the coverage network is directly affected by the performance of RF optical module. The purpose of this paper is to design a WCDMA RF optical module, which can fulfill the need of WCDMA fiber optic repeater and realize the coverage of WCDMA network.On the base of analysis of the GSM and CDMA RF optical module, this paper expatiates the theory of RF optical link and proposes a solution for WCDMA RF optical module. At first this paper brings forward a voltage control attenuator composed by PIN diode, which has good linearity, wide dynamic range and low cost. Then it discusses the theory for coupled line micostrip BPF and realizes a zig-zag micostrip BPF to attenuate spurious emission. After that this paper introduce a method using only one FSK chip to fulfill the function that was achieved by two chips in the past. This way is costly and develops the integration of this module. At last a cavity is designed to solve the EMC/EMI problem of the module.This paper introduces the design theory for each part and realization of the whole hardware. During this period, ADS and HFSS are applied to optimize the design, which predigests the design greatly. The WCDMA RF optical module has unique dual cavity construction and pluggable data transmission module, which realizes the modularization and flexible update ability of the module. This WCDMA RF optical module has passed the filed test for repeater supplier, all the parameters meet the access standard for WCDMA and achieves good performance.更多还原