电子秤控制电路的设计

黄冈职业技术学院

毕业设计说明书

课题名称电子秤控制电路的设计

系别

起讫时间：2010年10月1 日～2010 年10月31 日（共 5 周）

摘要

信息传输是人类社会生活的重要内容。从古代的烽火到近代的旗语，都是人们寻求快速远距离通信的手段。直到19实际电磁学的理论与实践已有坚实的基础后，人们开始寻求用电磁能量传送信息的方法。话筒的争论往往是最激烈而革命性的，从电子管到晶体管、从动圈到电容飞速、从微型话筒到金话筒，还有值得珍藏的纪念版话筒等。话筒又分为无线话筒和无线话筒，其线路虽有差异，原理是一致的，都离不开调制和解调，但却是单独的各用一套调制和解调线路，造成了不必要的浪费，使用也不方便。

无线话筒是一种不用导线传送音频信号的装置。由于当今无线通讯技术的进步，无线话筒的体积越来越小，重量越来越轻，方便人们随声携带，因此得到了越来越多人的认可，并且被人们广泛使用。调频无线话筒的原理是将声波信号通过麦克风转化为音频电信号，通过改变结电容来改变高频振荡器的输出频率，产生调频波，通过高频放大与选频，最终由天线辐射。

关键词调频；振荡电路；放大

Abstract

The intelligence transmission is the human society life important content. From ancient times's beacon-fire to the modern flag indicator, is the people seeks the fast remote communication the method. Had the solid foundation after 19 actual electromagnetics's

theories and the practice, the people start to seek with the electromagnetism energy pass-along message method. Microphone's argument often is most intense, but revolutionary, from electron tube to transistor, from moving coil to electric capacity rapid, from miniature microphone to golden microphone, but also has is worth the collection the commemorative edition microphone and so on. The microphone divides into the radio microphone and the radio microphone, although its line has the difference, the principle is consistent, cannot leave the modulation and the demodulation, but is actually independent respectively with set of modulations and the demodulation line, created the nonessential waste, the use has not been convenient.

The radio microphone is one kind does not need the wire to transmit the tonic train signaling the installment. Because is now wireless the mechanics of communication the progress, radio microphone's volume, the weight is getting smaller getting more and more light, the convenient people yes carry, therefore obtained more and more person's approvals, and is widely used by the people. The frequency modulation radio microphone's principle is transforms the acoustic signal through the microphone as the audio frequency electrical signal, changes high frequency oscillator's output frequency through the change junction capacitance, produces the frequency-modulated wave, with chooses the frequency through the high-frequency amplification, finally by antenna radiation.

Key word frequency modulation; Oscillating circuit; Enlargement

目录

引言....................................................... V 一、系统设计方案及要求...................................... V

（一）设计方案 .......................................... V (二）设计要求 .......................................... V

(三) 名词介绍 .......................................... VI

（四）系统框图 ........................................ VI 二、无线话筒的频段设计.................................... VII

（一）VHF甚高频波段................................... VII （二）无线电波在各频段的传播特性 ...................... VII （三）基本工作原理 ................................... VIII 三、电路设计............................................... IX

（一）语音信号调频设计 ................................. IX

(二)振荡电路的设计 .................................... IX

（三）振荡电路的选用 .................................... X （四）载波振荡模块 ................................... XIII （五）基本放大部分设计 ............................... XIII （六）发射部分电路设计 ................................ XV 四、电路的调试............................................ XVI

（一）减少电磁的干扰 .................................. XVI （二）发射距离的控制 .................................. XVI （三）元器件选择 ..................................... XVII （四）制作与调试 ..................................... XVII 五设计心得............................................. XVIII 致谢.................................................. XVIII 参考文献.................................................. XIX