【作者】 李吉光；

【导师】 曹明翠；

【作者基本信息】 华中科技大学 ， 物理电子学， 2005， 硕士

【摘要】 随着网络对传输带宽的要求越来越高,越来越多的网络设备被置于运营商的同一个机房中,由于超高速数据连接的需要,这些设备之间一般都采用光互联,并且连接的距离较短。因为长距离光传输技术成本较高,所以在短距离内采用长距离光传输技术不合适,而具有较高性价比的甚短距离光传输技术(Very Short Reach,VSR)是这种情况下的最好选择.本课题对甚短距离光传输系统进行了设计和测试。本文首先描述了系统中关键的信号转换模块的实现。给出了信号转换部分的总体结构。然后根据自顶向下的设计方法的原则,对发送模块和接收模块的逻辑进行了设计。包括在接收和发送方的数据信道中的帧定界符替换模块、数据映射校准模块、数据缓存模块、失同步和失帧报警恢复状态机、编码解码模块、循环冗余校验模块、双倍速率数据接口电路和接口电路等等子模块的设计和实现。然后根据逻辑电路的优化方法和调整系统芯片逻辑资源的布局,并采用芯片提供商提供的逻辑锁的方式对系统进行优化,使系统性能有很大提高。然后在对实验系统的信号格式,保护倒换方式进行分析的基础上,对其保护倒换提出了改进方案,并进行了分析,大大提高了系统的可靠性。然后介绍了系统测试板的设计中需要考虑的主要因素,包括信号完整性问题、电磁兼容性等问题,并根据理论要求,给出了在实验系统之中相应的措施,进行了印刷板板层参数、电源分割、布线的处理和布局布线设计,特别是低压差分信号接口的端接和布线的处理,完成了系统的电路原理图和印刷板图。经过测试,系统设计完全满足需要。本文给出了测试结果。并且就系统性能的进一步优化和本系统的设计在其他标准的甚短距离光传输系统之中的应用和拓展做了介绍和展望。给出了后期工作的建议。更多还原

【Abstract】 With the development of the networks capacity, more and more network devices are put together in the service provider’s office. Most of these devices are connected by the optical link in very short distance. The former long haul optical link scheme is not suitable under this condition because of high price. Thus the very short reach (VSR) optical transfer scheme comes out. The implementation and improvement of the VSR technology are shown in this paper. The overall structure of the system is shown at first. Then the design of key module-signal transformer module is shown. According to the top-down methodology, the designs the logic circuits of the transmitter and receiver are shown. The sub blocks include the substitutions of the framer limiter, data mapping and alignment module, the First In First Out module, the loss synchronization and lose framer state machine, the 8B/10B coder decoder, the Cyclic Redundancy Check module, the double data rate circuit and so on. Then, the entire circuit module is optimized by the logic circuit optimization methods and the proper routing of the whole module. By using the logic lock method provided by the vendor and soft, the performance of the design is optimized step by step. Then a novel switch protecting method is proposed based on the analysis of the signal format. The performance of this method is analyzed, the result shows that it improve the system reliability greatly. The design of the print board circuit of the VSR system is shown next. the high speed digital phenomena, signal integrity、electromagnetic compatibility, are expatiated in detail. The mechanism and solution of reflection、crosstalk、ringing, especiall the teminal of the low voltage differential signal, are also given. The overall scheme and circuit routing design of the system are shown. Finally, the satisfied test result and analysis of the system is shown. The improvement and extensional application of current sytem is also discussed in the end. Keywords: very short reach, parellel optical transimition, dignal transform, test board更多还原