GT-1DF西安光谷数据测试仪.ppt

GUANGGU munication ? 20 10 GUANGGU Corporation GT-1DF 数据通信测试仪培训教程 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 2 GUANGGU munication ? 20 10 GUANGGU Corporation GT-1DF 数据通信测试仪培训教程 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 3 GUANGGU munication ? 20 10 GUANGGU Corporation 基本知识仪表简介仪表外观仪表设置应用举例问题探讨主要内容 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 4 GUANGGU munication ? 20 10 GUANGGU Corporation 一、基础知识 概述?通信的目的是传递或交换信息,信息有语言、文字、数据、图文等多种形式。这些不同形式的信息必须变换成适合于在信道中传送的信号。从时域特性看,基本上可分为模拟信号和数字信号两种形式,常按传输信道中所传输的信号类别分为模拟通信和数字通信两大类。由于数字通信与模拟通信相比具有信息传输噪声不积累等显著优越性, 近年来得到了迅速发展。数字通信已成为主要的通信方式,所以我们主要讨论数字通信系统传输特性的测量。 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 5 GUANGGU munication ? 20 10 GUANGGU Corporation ?衡量数字传输系统可靠性的主要指标是误码,这个指标直接与通路系统和信道质量有关。?误码是指在传输过程中接收与发送数字信号之间单个数字的差异。根据误码的定义,误码测量必须逐位比较发送端的输入信号和接收端的接收信号。由于在系统运行时,发送端发送的业务信号是随机的二进制码流,所以作逐位比较是不可能的,据此误码检测手段分为开业务(在线)和停业务(离线)的误码测量两种。 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 6 GUANGGU munication ? 20 10 GUANGGU Corporation 开业务的误码检测常用于传输系统本身的监测, 如SDH 的开销字节安排中就有强大的误码监测功能,这种在线误码检测实现简单,能长时间