现代通信电路（课程设计）目录一、设计题目..............................................................1二、设计内容..............................................................12.1AM广播通信系统..............................................12.2FM广播通信系统..............................................22.3半双工调频无线对讲机.....................................32.4论证：...............................................................3三、实现方法.............................................................33.1载频信号产生模块............................................43.1.1论证：.......................................................53.2调制器...............................................................63.2.1论证...........................................................83.3解调器...............................................................83.3.1论证：.......................................................93.4混频器.............................................................103.4.1论证：....................................................123.5高频谐振电压放大器.....................................123.5.1论证：.....................................................153.6高频功率放大器............................................153.6.1论证：.....................................................17四设计平台...............................................................184.1硬件平台.........................................................184.2软件平台.........................................................18五、电路调试............................................................195.1AM发射机调试...............................................195.2AM接收机调试...............................................205.3调幅通信系统联调..........................................205.4调制信号幅度小的问题...................................255.5解调信号不稳定的问题...................................255.6连接后的实际电路...........................................26六、电路仿真............................................................276.1LC振荡器：....................................................276.2振幅调制器：..................................................296.3振幅信号的解调：..........................................31七、心得体会............................................................32八、附录....................................................................338.1GP4实验板模块分布图....................................33一、设计题目模拟通信系统的设计与实现二、设计内容设计并实现一个模拟通信系统，系统总体框图如图1所示。具体方案可以采用AM、FM或者无线对讲系统。音频放大器调制器激励放大输出功率放大载波振荡器天线开关高频放大混频器中频放大与滤波解调器音频放大器话筒本地振荡器扬声器变频器2.1AM广播通信系统图2a中波调幅发射机图2b超外差中波调幅收音机2.2FM广播通信系统图3FM接收机2.3半双工调频无线对讲机图4半双工调频无线对讲机2.4论证：AM(调幅)是用音频信号去调制高频载波的振荡幅度!形成由音频信号包络振幅的调幅载波!FM(调频)是用音频信号去调制高频载波的振荡频率!形成随音频信号而在一定宽带内变频的调频载波!经过小组内讨论我们选择了AM广播系统三、实现方法3.1载频信号产生模块实现方法1：LC振荡器可以用西勒电路，也可用克拉泼电路图5正弦波振荡电路将开关S1的1拨下2拨上，S2全部断开，由晶体管N1和C3、C10、C11、C4、CC1、L1构成电容反馈三点式振荡器的改进型振荡器——西勒振荡器，电容CCI可用来改变振荡频率。振荡器的...
