How can there be different fequencies (it’s a difference in wave-lengths right?) but the tone of the music doesn’t seem altered by it.
In: 85
Are you asking: Despite having multiple radio waves (e.g. from different frequencies / radio stations) occupying the same space, how are the sounds they encode not mixed together when we finally hear them?
Terrestrial radio stations have a Carrier frequency. For example, 88.3 MHz. Another station within a certain range is required to operate at a different frequency. This is because if two radio signal sources with the same frequency operate in a certain range, depending on their power output, they will indeed cause interference with each other.
Each station is assigned a “channel” which has a bandwidth of around 200kHz.
The size of the bandwidth determines how much raw information you can transmit on that channel without interfering with other channels.
In simplistic terms, music can occupy a range of 20Hz to 20kHz. To encode this as an FM signal, we need to be able to modulate (change the frequency) of the carrier signal by around 20kHz. The rest of the 200kHz bandwidth is used for Stereo (left+right) signal, other information and spacing to avoid overlapping with other stations.
As to how radios lock on to a frequency that changes, you can look into superheterodynes and phase-locked-loops.
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