I have a basic question concerning ultrasound A-scans. Such an A-scan might typically look as follows (source: https://img.medscapestatic.com/pi/meds/ckb/18/7418tn.jpg):
I understand that the x-axis is the time axis but I'm unsure about the y-axis. In the literature, I can find that the y-axis and the amplitudes of the signal represent the "intensity of reflected sound" but what's the unit of this intensity? Or to put it in other words: What would an amplitude value of, say, 0.2 actually mean?
Thank you very much.