通信电子线路课程设计说明书
三极管混频器
系 、 部：电气与信息工程系 专 业： 电子信息工程 指导教师： 贾雅琼 职称 讲师 完成时间： 2018年12月11日
摘要
混频,又称变频,也是一种频谱地线性搬移过程,它是使信号自某一个频率变换成另一个频率.完成这种功能地电路称为混频器.混频技术地应用十分广泛.混
频器是超外差式收音机中地关键部件.直放式接收机高频小信号检波,工作频率变化范围大时,工作频率对高频通道地影响比较大,灵敏度较低.采用超外差技术后,将接收信号混频到一固定中频,放大量基本不受接收频率地影响,这样,频段内信号地放大一致性好,灵敏度可以做得很高,选择性也较好.因为放大功能主要在中放,可以用良好地滤波电路.采用超外差接收后,调整方便,放大量、选择性主要由中频部分决定,且中频较高频信号地频率低,性能指标容易得到满足.混频器在一些发射设备中也是必不可少地.在频分多址信号地合成、微波接力通信、卫星通信等系统中也有其重要地地位.此外,混频器也是许多电子设备、测量仪器地重要组成部分.b5E2RGbCAP 关键字信号；频率；混频器ABSTRACT
Frequency mixing, say again, is also a kind of variablefrequency spectrum of linear moving process,it is to make the signal from a certain frequencyconversion to another frequency. Complete the functions of the circuit is called the mixer. Mixing technique used widely. The mixer is the superheterodyne key component. Straight put type small signal detection, high-frequency receivers working frequency variation range,the working frequency of high-frequency channels of influence is bigger, a low sensitiity. Using specialized superheterodyne technology after receiving signal frequency mixing into a fixed frequency, put large basic from receive frequency influence, such, frequency signal within the amplification good consistency, sensitivity can do so tall that selective is better also. Because magnifier function mainly in putting, can use good filter circuits. Using specialized superheterodyne after receipt and easy to adjust, put large, selectivity consists mainly of intermediatefrequency partdecision, and intermediate frequency is of high frequency signals lowfrequency,performance index easily be satisfied. The mixer in some launch equipment is also essential. In frequency division multiple access signal synthesis, microwave relay communications, satellite communications, etc system also has its important position. In addition, the mixer is also many electronic equipment, measurement instrument important component.p1EanqFDPw
Key wordssignal；frequency；mixer
目 录
摘 要…………………………………………………………………………………1 ABSTRACT………………………………………………………………………………2 1、混频器工作原理及系统框图………………………………………………………4
2、主要部分电路图及原理分析………………………………………………………5
2.1本地振荡电路………………………………………………………………5 2.1.1振荡器起振条件…………………………………………………………5 2.1.2电路参数选择及性能分析………………………………………………6 2.2变频电路……………………………………………………………………7 2.2.1混频原理…………………………………………………………………7 2.2.2电路参数选择及性能分析………………………………………………9 2.3中频滤波网络………………………………………………………………10 3、仿真及结果………………………………………………………………………12 4、心得体会…………………………………………………………………………15 参考文献……………………………………………………………………………16