Signal transmission, transmission mode

The signal is transmitted as if you were making a sound. The transmitting device is mainly composed of resistors and inductors, forming a resonant circuit to generate the desired carrier frequency. The transmitter transmits the modulated signal through the antenna into the air for the receiving device to receive. It's like when you shout through a loudspeaker so that your distant friends can hear you.

Reception of signal

Once you get the signal, it's like when you hear a friend Shouting and you need to understand what he means. First, the audio information in the high-frequency carrier signal needs to be extracted by demodulator. The process of demodulation involves filtering to remove the high-frequency components, leaving only the low-frequency audio signal. The demodulation methods of AM signal and FM signal are different. AM signal is demodulated by envelope detector, FM signal is demodulated by frequency discriminator.