pulse echo measurements Flashcards
animals that use echolocation
bats and dolphins
frequency of bats chirp
50-1000kHz, lasting 3 milliseconds
how does echolocation help bats see
sensitive ears, brain measures time delay + calculate distance = speed x time
how do dolphins differ from bats
dolphins can build a mental image of what’s around them
speed of sound in air
330ms-1
human uses for pulse echo measurements
sonar, medical imaging, air traffic control, distance of asteroids and the moon
when do humans use pulse echo measurements
when other methods are difficult / dangerous
low frequency sounds travel
further than high frequency sounds
calling at high frequency (more often) gives bats
clearer images - more detailed more precise location as they get closer
as frequency of chirps increases
wavelength decreases
when wavelength decreases
resolution increases as more detail as it refracts less
intensity of a progressive wave
the gradient power passing through a surface per unit area
bats echolocation can be reflected off an objected up to
5m away - any further and echo is too attenuated
I=P/A
I=P/4PIR2
