通信电子线路课程设计说明书
三极管混频器
系 ： 电气和信息工程
学 号：11401340336 姓 名：王凯 专业班级：通信11-03班 指导老师： 张松华
时 间: 2013.12.16
摘要
混频器在通信工程和无线电技术中，使用非常广泛，在调制系统中，输入的基带信号都要经过频率的转换变成高频已调信号。在解调过程中，接收的已调高频信号也要经过频率的转换，变成对应的中频信号。特别是在超外差式接收机中，混频器使用较为广泛，如AM 广播接收机将已调幅信号535KHZ-一1605KHZ要变成为465KHZ中频信号，电视接收机将已调48．5M一870M 的图象信号要变成38MHZ的中频图象信号。移动通信中一次中频和二次中频等。在发射机中，为了提高发射频率的稳定度，采用多级式发射机。用一个频率较低石英晶体振荡器做为主振荡器，产生一个频率非常稳定的主振荡信号，然后经过频率的加、减、乘、除运算变换成射频，所以必须使用混频电路，又如电视差转机收发频道的转换，卫星通讯中上行、下行频率的变换等，都必须采用混频器。由此可见，混频电路是使用电子技术和无线电专业必须掌握的关键电路。
本文通过MC1496构成的混频器来对接收信号进行频率的转换,变成需要的中频信号.
Abstract
The mixer in communication engineering and radio technology, application is very extensive, in modulation system, the input of baseband signal are throughfrequency conversion into a high frequency modulated signal. In the demodulation process, the received modulated high frequency signal afterfrequency conversion, into intermediate frequency signals corresponding to.Especially in the superheterodyne receiver, mixer is widely used, such as AMradio receiver will be amplitude modulated signal 535KHZ- a 1605KHZ to become 465KHZ IF signal, image signal television receiver will have a 870M48.5M to become 38MHZ of intermediate frequency image signal. In mobile communication, a frequency and the two frequency etc.. In the transmitter, in order to improve the stability of transmitting frequency, uses the
multistagetype transmitter. With a low frequency of the quartz crystal oscillator as the main oscillator, generating the main oscillation signal of a frequency is verystable, and then through the frequency plus or minus, multiply, divide intoradio frequency, we must use a mixer circuit, such as converting TV transposer transceiver channel, the uplink, downlink frequency in satellitecommunication transform, must be in the mixer. Thus, mixing circuit is the key module of Applied Electronic Technology and professional radio must master.
This paper is composed by MC1496 conversion mixer to the frequency of the received signal, a signal is needed.
目 录
摘要 ..................................................................... 1 第一章 系统分析 ....................................................... 3
1.1设计课题任务 ...................................................... 3 1.2课题基本原理 ...................................................... 2 1.3混频电路的分类 .................................................... 4 1.4混频电路的实际使用 ................................................ 5 第二章 软件介绍 ...................................................... 6
2.1 工具的选择——Multisim 10 简介 ................................... 6 2.2 Multisim 10 的特点 .............................................. 6 第三章 设计课题的仿真分析晶体管混频器虚拟实现 ........................ 7
3.1设计课题的参数选择 ................................................ 7 3.2晶体三极管混频器设计及课题的仿真结果 .............................. 9 3.3设计课题的仿真调试 ............................................... 11 第四章 结论.......................................................14 致谢 .................................................................... 15 参考文献 ................................................................ 16 附录：Multisim 扫频仪的介绍 .............................................17