What is the principle of two-tone stereo?

Dual channels create conditions for stereo radios. Because people's ears can distinguish the distance and direction of each sound source, it sounds spatial (or stereoscopic). In the sound reproduction system, two or more channels are used to make the relative spatial position of the sound source felt by the listener close to the relative spatial position of the actual sound source, which is called stereo. Stereo includes two-channel stereo, four-channel stereo, Dolby stereo, Dolby surround sound and Dolby AC-3 digital surround sound. Radio broadcasting with stereo technology is called stereo radio. Take a two-channel stereo radio as an example. Two-channel stereo radio broadcasts two sound signals corresponding to the left front and right front directions of listeners through one or two broadcast channels with different frequencies. The listener can recognize the relative position of the sound source and generate a sense of stereo when receiving it with the stereo radio of the two-channel playback system. If you use an ordinary radio, you can also receive the same program content, but there is no three-dimensional sense.