Amplitude is the magnitude — the “height” — of a wave.1 For a
radio wave it corresponds to signal strength, which a
receiver reports as a power level in dBm or
dBFS.
Amplitude is the height of the wave; greater amplitude delivers more power to the receiver.
How it works
A larger amplitude carries more power. As a signal spreads from a transmitter and
passes obstacles, its amplitude falls (path loss), which is
why distant signals are weaker.
Relevance to SDR
Varying amplitude is the basis of amplitude modulation
and part of what an IQ sample encodes (its distance from the
origin). A signal’s amplitude relative to the noise floor
sets its SNR.
Sources
Amplitude — Wikipedia, on the magnitude of a wave’s oscillation. ↩
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