I know that it’s electrowaves but how does it become sound again ? How are there several channels ?
In: Technology
Sound is just fast vibrations in air that happen at around 20-20000 times a second
Radio waves are fast vibrations in the electromagnetic field that happen around several millions to hundreds of millions of time a second
AM radios essentially used the fact that sound is much slower than radio waves and they just change the strength of the radio signal as the audio signal changes. A radio would essentially just filter out anything higher than 20 khz and you’d just be left with the original sound signal to send to the amplifier and speaker
As the frequency of the radio signal doesn’t really affect the audio sent through you can send multiple radio signals at the same time so long the frequency is different, and another filter inside the radio would take care of isolating only one as selected by a knob
FM uses exactly the same idea but instead of changing the power to the transmitter it just transmits a slightly higher frequency for louder sounds, a different circuit is still able to decide it back to sound, and this change to how the wound is encoded results in less distortion
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