《电话光纤传输系统设计与开发》解析.doc

《电话光纤传输系统设计与开发》 实验指导书 （基于RZ8644型光纤实验系统） 侯阿临 2013年9月 目 录 引言 光纤实验系统介绍···················································3 一、结构简介·······························································3 二、配套仪器·······························································4 三、系统结构框图···························································5 四、系统特点·······························································5 五、液晶显示菜单···························································5 六、使用注意点·····························································7 电话光纤传输系统设计与开发·············································8 一、实验目的·······························································8 二、实验仪器·······························································8 三、基本原理·······························································8 四、实验步骤·······························································16 五、测量点说明·····························································17 六、实验结果·······························································18 引言 光纤实验系统介绍 RZ8644型光纤实验系统是为了配合《光纤通信系统》的理论教学而设计的实验系统。它一方面结合了当今光纤通信原理课程的教学与改革，另一方面结合了当今光纤通信发展方向和工程实际应用状况。这套系统采用功能模块化设计，各模块对外开放。除了配合完成理论教学外，还可以训练增强学生的实际应用能力，完成模块的二次性开发。 一、结构简介 本实验系统可分为电端机模块、光通信模块、管理控制模块、电源供给模块等四大功能模块，每个功能模块又是由许多子模块组成： 电端机模块 电话用户接口模块 此模块为电话输入、输出接口，由电话专用接口芯片PBL38710实现。它包含向用户话机恒流馈电、向被叫用户话机馈送铃流、用户摘机后自行截除铃流，摘挂机的检测及音频或脉冲信号的识别，用户线是否有话机的识别，语音信号的2/4线混合转换，外接振铃继电器驱动输出等功能。其各项性能指标符合邮电部制定的有关标准。 本模块分为用户A，B两个模块。 PCM编译码模块 此模块采用专用芯片TP3057来实现PCM编译码功能，可完成用户A、B两路话音信号的编译码功能。 DTMF双音多频检测模块 此模块由专用芯片MT8870来完成DTMF分组滤波和DTMF译码功能，输出相应16种DTMF频率组合的4位并行二进制码。实际应用中，一片MT8870可以至多接入检测16路用户电路的DTMF信号。 记发器模块 此模块主要完成局内、局间电话用户拨叫号码的识别、交换控制功能。 计算机通信接口模块 此模块由USB和RS232串口两通信接口组成，完成计算机与本实验系统的数据交换传输功能。也为学生开发上层通信软件提供了良好的硬件平台。 数据发送单元模块 此模块主要完成各种测试信号的产生、各种线路编码、数据的复接及一些辅助性功能。 产生的数字信号有：各种频率的时钟、方波、M序列、矩形窄脉冲等、 线路编码功能有：AMI码、HDB3码、CMI码、5B6B码、5B1P码、扰码等 数据的复接：多种类型数据进行时分复接输出 数据接收单元模块 此模块主要完成接收数据的时钟提取