收音机的原理是把从天线接受到的高频信号，经检波还原成音频信号，送到扬声器变成音波把接收到的电台高频信号，用一个变频级电路将它转化为频率固定的中频信号，然后再对这个中频信号进行多级放大，再检波，低放。由于不同频率的无线电波用途较广、接受的-The principle is the radio frequency signal received from the antenna, the reduction by the detector into an audio signal to the

RFID射频识别，包括了该工程的所有文件。-RFID radio frequency identification, including all the files in the project.

1、正弦信号发送器 2、射频信号接收和分析器(1, sine signal transmitter 2. Radio frequency signal receiving and analyzer)