BasicB-005-007-003
Why is the range of frequencies from 20 Hz to 20 kHz termed audio frequencies?
B
Answer
Transmitters, receivers, and measurements
Type
A
Because RF signals in this range can be directly converted to sound
B
Because the human ear can sense sound in this range
C
Because sound can be in this range but it's too low for RF signals
D
Because this is the speaker response range of a modern SSB receiver
Answer Notes
The term 'audio' specifically relates to human hearing and sound. Therefore, frequencies between 20 Hz and 20 kHz are termed 'audio frequencies' (AF) purely because these are the rates of vibration that the human ear is biologically capable of sensing as sound.
Radio Frequency (RF) signals cannot be directly converted into sound without a receiver circuit to demodulate them. Furthermore, while modern communication speakers are built to reproduce sounds in this range, the biological capability of the human ear is the fundamental reason for the terminology, not the hardware.
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What approximate range of frequencies can most humans hear?
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Electrical energy at a frequency of 7125 kHz is in what frequency range?