小 功 率 调 幅 发 射 机 论 文
大连大学论文
学 生 姓 名：
学 生 姓 名： 指 导 教 师： 张玉霞 专 业： 通信工程 课 题 名 称： 小功率调幅发射机 完 成 日 期：
大连大学 Dalian University
大连大学论文
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摘 要
我们的课题是以电子线路课程设计为背景，查阅大量教学文献，并结合专业基础课程教学需要，以教学内容为基础，小组分工合作完成了小功率调幅发射机从设计、仿真、调试等一系列设计工作。
小功率调幅发射机包括了主振级、被调级、推动级、音频处理器、功率放大末级等几个主要的模块。根据原理框图拟定大致的方案，在由技术指标设计出各部分电路参数。主振级电路是LC正弦整荡器，电路组装调试合格后，将输出信号由发射机经耦合电容送到推动级将信号加以放大，主振器采用频率稳定度高的石英晶体振荡器，并在它后面加上缓冲级，以削弱后级对主振器的影响，经过音频放大后的信号在高频部分的末级功放实现对载波信号的调幅。推动级采用小信号谐振放大器电路，应注意该级谐振在信号频率上，连接本电路时一定先调整好该级正常工作。功率放大级采用丙类谐振功率放大器电路。调幅信号的是在功率放大实现的情况下进行。整机发射与接收是在前面联调的基础上，应首先测量发射机工作频率、输出功率，在满足要求的情况下，在进行实际的发射与接受联机实验，同时测试发射效果。
在实验的过程中我们逐步了解到小功率调幅发射机常用于通信系统和其它无线电系统中，特别是在中短波广播通信的领域里更是得到了广泛应用。原因是调幅发射机实现调幅简便，调制所占的频带窄，并且与之对应的调幅接收设备简单，所以调幅发射机广泛地应用于广播发射。
关键字：小功率发射机；主要模块；电路设计；仿真
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Abstract
Our task is to Electronic Circuit Design background, access to a large number of teaching literature, combined with professional foundation courses teaching needs, content-based teaching, the group completed the division of labor from low-power AM transmitter design, simulation, debugging series complete design work.
Low-power AM transmitter includes a main vibration level is adjusted level, to promote several major module level, the audio processor, power amplifier final stage and so on. According to a rough block diagram of the preparation program, devised by the technical specifications for each part of the circuit parameters.Main vibration level circuit LC Sine oscillator, circuit assembly debugging qualified, the output signal from the transmitter via a coupling capacitor to promote the level of the signal to be amplified, the main oscillator uses high frequency stability of quartz crystal oscillator, and behind it with a buffer stage to weaken the influence of the master oscillator stage, after the audio signal amplified in the high frequency part of the final amplifier to achieve the carrier signal amplitude. Push-class small-signal amplifier circuit resonance, you should note that the resonance frequency of the signal level, the connection of the circuit must first adjust the level to work properly. Class C power amplifier stage with a resonant power amplifier circuit. AM signal is carried out in the case of the power amplifier implementation. Machine transmit and receive is based on the front of the FBI, should first measure the transmitter operating frequency, output power, to meet the requirements of the situation, making the actual launch and acceptance of the online test, while the test launch effect.
During the experiment, we gradually learned that low-power AM transmitters commonly used in communication systems and other radio systems, particularly in the field of short-wave radio communications where it is widely used. The reason is simple amplitude modulation AM transmitter to achieve narrow band modulation percentage, and the corresponding device simple AM receiver, AM transmitter so widely used in broadcast transmission.
Keywords: low-power transmitters; the main module; circuit design; simulation
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目 录
摘 要............................................................................................................................................ I Abstract ............................................................................................................................................ II 目 录 .............................................................................................................................................. III 1小功率调幅发射机的基本原理 .................................................................................................... 1
1.1小功率调幅发射机的总体认识 ........................................................................................ 1 1.2调幅发射机的原理 ............................................................................................................ 1 1.3电路各部分工作原理 ........................................................................................................ 2
1.3.1主振级工作原理 .................................................................................................... 2 1.3.2高频电压放大器工作原理 .................................................................................... 3 1.3.3高频功率放大器工作原理 .................................................................................... 3 1.3.4音频功率放大工作原理 ........................................................................................ 3 1.3.5振幅调制工作原理 ................................................................................................ 4
2设计思路........................................................................................................................................ 5
2.1设计方案的确定 ................................................................................................................ 5 2.2参数计算 ............................................................................................................................ 6
2.2.1技术指标 ................................................................................................................ 6 2.2.2计算 ........................................................................................................................ 6
4总体电路设计 ................................................................................................................................ 7
4.1总体电路 ............................................................................................................................ 7 4.2等效电路 ............................................................................................................................ 7 5电路仿真........................................................................................................................................ 8
5.1 调试步骤及结果 ............................................................................................................... 8
5.1.1主振级 .................................................................................................................... 8 5.1.2缓冲级 .................................................................................................................... 9 5.1.3高频放大级 .......................................................................................................... 12 5.1.4音频放大级： ...................................................................................................... 13 5.1.5调幅级 .................................................................................................................. 15 5.1.6功率放大级 .......................................................................................................... 16 5.2整体电路 .......................................................................................................................... 17 5.3 调试过程中遇到的问题 ................................................................................................. 18 6心得体会...................................................................................................................................... 19 7原件清单...................................................................................................................................... 20 参考文献......................................................................................................................................... 23 附录 ................................................................................................................................................ 24
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