I know that the equation of armonic motion depends on three parameters: amplitude, frequency, phase. When a radio is receiving a signal from another radio, they’re on the same wavelength, that’s measured by period/frequency; so I guess that’s a “fixed” variable, or at least a variable that doesn’t carry information, but permits to choose which signal to listen to.
So how does a wave transfer information? Is it because the other two parameters change (or at least its amplitude).
In: Engineering
There are two types of radio: AM (Amplitude Modulated) and FM (Frequency Modulated).
AM radio carries information by keeping a constant frequency, but varying the amplitude of the wave.
FM radio carries information by varying its frequency. The general audible range for humans tops out at about 20kHz (it depends a lot on things like age), so if you’ve got two FM signals that are set 1MHz apart, then both signals can vary by 20kHz without interfering with each other. You can “subtract” the constant 1MHz part of the signal out from the variance using electronics, which will leave you with just the original 0-20kHz signal.
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