短波调频接收机
摘要
采用天线接收外来短波，应用超外差式方法对外来信号进行处理，并通过功率放大器放大音量，以便得到清晰准确的信息。由一个调谐回路作为输出电路，并以一个调节可变电容来选择不同频率的信号，由本机振荡、混频和选频三部分电路组成变频电路，将输入的不同频率的高频信号变换成固定的465kHz的中频信号，由一个二极管检波器进行检波，再由低放电路和OTL电路进行功率放大，最终得到准确有用的信息。利用超外差式方法来处理短波信号，具有易得到足够大而且比较稳定的放大量，频率特性的选择性较好，容易调整等优点。
关键词：超外差，中频放大，限幅器，检波，音频功放
Abstract
Use of foreign short-wave antenna, external application of superheterodyne method of signal processing, and volume through the power amplifier in order to get clear and accurate information. By a tuned circuit as the output circuit, and adjust the variable capacitor to select a different frequency signal, by the local oscillator, mixer and the selected frequency inverter circuit composed of three parts of the circuit will enter the high-frequency signals of different frequencies converted into fixed The 465kHz IF signal by a diode detector to detector, and then from low-amp circuit and the OTL power amplifier circuit, and ultimately accurate useful information. Methods used to deal with short-wave superheterodyne signals are easy to get large enough and put a lot more stable, better frequency selectivity, easy to adjust and so on.
Keywords: specialized superheterodyne, intermediate frequency amplifier, the limiter, detection, audio power amplifier
目 录
1 绪论5
1.1 无线接收机的发展概况5
1.1.1 无线接收机的历史5
1.1.2 我国无线接收机的发展及状况5
1.1.3 无线接收机的调制方式6
1.2 短波的基本介绍7
1.3 超外差式接收机7
1.4 超外差式接收机的系统分析8
2 超外差式接收机电路分析10
2.1 输入回路10
2.2 变频回路11
2.2.1 混频电路11
2.2.2 选频电路13
2.3 中频放大电路13
2.4 限幅器14
2.5 检波电路15
2.6 自动频率微调控制电路15
2.7 音频功放电路16
2.7.1 低频放大电路16
2.7.2 低功率放大电路17
2.8其他电器件18
3结论20
参考文献21
感谢辞22
