文档介绍：天津大学硕士学位论文测绘工程中无线语音及数据传输系统设计姓名:李杰申请学位级别:硕士专业:通信与信息系统指导教师:沈保锁 20071201 中文摘要利用无线通信信道的短距离传输语音及数据业务,是近年来发展很快的一门技术。在电力、水利、测绘工程、GPS数据采集、远程设备监控,高危场所检测等领域,由于自然及地域原因,部分工程不能实施有线语音和数据的连接,因此无线数据传输就能在这种情况下发挥特殊的作用。通过无线电方式,以电磁波为载体传输语音和数据的方式称为无线语音和数据传i:;f;基于已有的无线网络系统也可以做到无线数据传输,例如GPRS、CDMA 1X、SMS等,但通过这种运营系统的数据传输往往会出现数据延时、在网络拥挤状态下失效的问题,而且在边远地区也无法实现网络的覆盖。所以,确保实时的语音和数据无线传输,保证语音和数据采集、监控等正常进行,必须有专用的硬件设备和通讯条件。本设计根据测绘工程对无线语音和数据传输系统的要求设计了相应的硬件系统。其中语音传输使用模拟调频技术,在1 44MHz~ 148MHz频段上,实现了话筒输入和线路输入语音信号的小功率远距离单工发送和接收。数据通信采用FSK调制方式,主、从机可实现智能控制通信,可连接多达256个从站,构成一点对多点的单工无线呼叫系统。从站号码可任意改变,主站可拨号选呼和对全部从站群呼,在语音通信同时可传送信息数据,使用液晶显示器显示英文和汉字短信及站号信息。本系统可实现无失真的语音传输,且具有数据传输误码率低的特点。关键词: 测绘工程无线语音和数据频移键控群呼短信 ABSTRACT ItdeVelops Very fast in recent years that the technology,which voice and data transmit through munication domain likes electric power, irrigation works, mapping engineering,GPS data coJIection,long—distance equipment stakeout and control,high danger fieJddetect and so on,owing to nature and clime,wire transmits ofvoice and data isimpossible insome proiects. Inthat status,wireless data transmit wi undergo aspecial reaction. Via wireless model. transmits of voice and data base on ic wave be called wireless voice and data transmit: Some works known like and works could do that work, but use these svstems transmit data sometimes be delayed, or data invalidation work iam, work can not cover with far from the center area. insure voice and data transmit in . and data collection. stakeout and controI process in the course of nature normalIv, special hardware equipment munications condition are needed. Base on require of mapping engineering ,Analog signals frequency modulation technique was adopted in our design. In the frequency interval of 44~1 48IⅥHz,it was realized that voice signals were inputted through microphone and long host and subordinate machines can undertake munication bv frequency shift keying (FSK) modulation mode. There are 256 subor