AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency
"David L. Wilson" wrote in message
news:Wcyki.7231$MV6.3335@trnddc01...
"Hein ten Horn" wrote in message
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So take another example: 25000 Hz and 25006 Hz.
Again, constructive and destructive interference produce 6 Hz
amplitude variations in the air.
But, as we can't hear ultrasonic frequencies, we will not produce
a 25003 Hz perception in our brain. So ther's nothing to hear,
no tone and consequently, no beat.
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If one looks at an oscilloscope of the audio converted to voltage, one
still can see the 6Hz variations on the 25003 Hz and still refers to those
as tone and beat. These exist in mathematically formulation of the
resulting waveforms not just as something in the brain.
What is the mathematical formulation?
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