《无线对讲系统接收子系统的设计》-毕业论文.doc

PAGE 精品 摘 要 无线对讲机作为一种简单的通信工具，由于它不需要中转和地面交换机站支持，就可以进行移动通信。目前广泛应用于生产、保安、野外工程等领域的小范围通信工程中。 无线对讲机技术是很多无线移动通信技术的基础，目前应用较广泛的蜂窝式移动电话技术，就是在无线双工对讲机的基础上，发展起来的新兴现代通信技术。很好的熟悉掌握无线对讲机内部电路的工作原理和测试、调整技术，对今后从事通信工程领域的技术工作，无疑是十分重要的。 本文主要建立了无线对讲系统的接受子系统的模型，其中主要包括信号频率的选择、频率的变换方式的选择、及信号功率的放大等方式及的选择。此外，本文还主要运用超外差收形式的构建对讲机接收系统。它主要由天线输入回路、接收带通滤波器、高频信号放大器、第一本振单元电路、第一混频电路、中放级、检波级、低放级及电源等部分组成。超外差收音机的主要工作特点是:采用了变频措施。输入回路从天线接收到的信号中选出某电台的信号后，送入变频级，将高频已调制信号的载频降低成一固定的中频，然后经中频放大、检波、低放等一系列处理，最后推动扬声器发出声音。这一变频措施，是超外差收音机性能得以改善的关键，也是分析超外差接收重点。 关键词： 调频 混频器 滤波器 功率放大器 The design of a receiving system for a Wireless Interphone Student:JIANG caiyun Teacher:SHEN zhuojun Abstract: Interphone is an simple communication equipment. With Wireless Interphone We can complete mobile communication service without the support of the transfer station . Wireless Interphone has been used wildly in the field of production and so on .The technology of frequency division doplex wireless interphone is the base of our modern mobile communication systems . In this thesis ,I build a model for a receiver system of a wireless interphone .And I explain how to chose the frequency of the carrier .how to change the frequency of the signal and how to select the way to enlarge the signal power. In my thesis , the receiver system is based on the technology of superheterodyne .There are 7 parts in this system ,they are: 1 .receiving antenna 2 . receiving band pass filter. 3.high frequency power amplify. 4.the first frequency mixing circuit 5.the second frequency mixing circuit. 6. low frequency amplify 7 .power surce circuit I use frequency mixing technoloy in this system. We send the signal from receiving antenna to frequency translation circuit.In the frequency translation circuit,we translate the high frequency signal into a middle-frequency signal , Key words: Frequency modulation Frequency mixer Filter Power magnifier 目 录 TOC \o 1-3 \h \z \u HYPERLINK \l _Toc169593923 摘 要 PAGER