1933年，世界上第一台发射机诞生。美国发明家阿姆斯特朗发明了短波（FM）收音机。1939年,FM发射机的发明者阿姆斯特朗在美国建立了第一个FM广播的发射站。同年,调幅收音机开始在美国出售。从此FM发射机技术开始迅速发展。在各行各业中得到应用，尤其是小功率FM发射机的应用更为广泛。. 论文是关于小功率调频发射机电路的设计。通常小功率发射机采用直接调频方式，其中调频振荡级主要是产生频率稳定，中心频率符合指标要求的正弦波信号，且其频率受到外加音频信号电压调变，缓冲级主要是对调频振荡信号进行放大，以提供末级所需的激励功率，同时对前后级起有一定的隔离作用，为避免末级功放的工作状态变化而直接影响振荡级的频率稳定度。功放级的任务是确保高效率输出足够大的高频功率，并馈送到天线进行发射。
论文设计了一个FM调频发射机，它由音频信号处理、调频信号和功率放大发射三部分组成。音频信号由麦克风和音频线输入，经过音频信号处理电路的限幅、低通滤波和混合后，得到立体声复合信号。复合信号经调频调制电路调制后，通过功率放大器放大，经发射电路，从天线发射出去。
关键词：调频；发射机；天线；高频
Abstract
In 1933, the world's first transmitter.Armstrong American inventor invented the short-wave radio (FM).In the United States in 1939, the inventor of the FM transmitter Armstrong first FM radio station was established.That same year, am sold in the United States.From now on FM transmitter technology began to develop rapidly.Has been applied in all walks of life, especially the application of small power FM transmitter.. The paper is about a small FM transmitter power circuit ually small power transmitter adopts direct frequency modulation method, including the oscillator stage mainly produce frequency stability, conform to the requirements of the indicators of center frequency sine wave signal, and the frequency of audio signal voltage modulation, buffer stage is mainly to FM oscillation signal amplifier, to provide the necessary level at the end of the driving power, at the same time there is a certain isolation effect to the level before and after, to avoid the last stage amplifier working condition changes directly affect the level oscillation frequency stability.Power amplifier level's mission is to ensure high efficiency high frequency power output is large enough, and feed to the antenna to launch.
Paper designed a FM transmitter, it consists of audio signal processing, frequency modulation signal and power amplification launch of three parts.Audio signals by a microphone and audio input line, after the audio signal processing circuit of the limiter, low-pass filtering and blend, get the stereo composite posite signal after modulation frequency modulation circuit, through the power amplifier amplification, the transmission circuit, from the antenna to launch out.
Keywords: frequency modulation; transmitter; antenna; high frequency
目录
引言 (1)
1 设计内容和意义 (1)
1.1 设计目的 (1)
1.2 设计要求 (1)
2 发射机简介及原理 (2)
2.1 调频发射机简介 (2)
2.2 设计整体思路： (2)
2.3 基本原理 (2)
2.4 调频发射机的原理图 (3)
2.5元器件说明 (3)
2.5.1 BA1401 (3)
2.5.2 三端稳压电源调整器78L05 (4)
3 模块说明 (5)
3.1 音频输入模块 (5)
3.2 振荡模块 (5)
3.3 放大和发射模块 (5)
3.4 调频发射机的主要技术指标 (5)
3.4.1 工作频率范围 (5)
3.4.2 发射功率 (5)
3.4.3 频率计算 (5)
5 电路的调试 (5)
5.1 电路的调试 (5)
6 实验的总结与心得体会 (6)
谢辞 (7)
参考文献 (8)
附录 (9)
