I'm looking at communicating digital data through the air as soundwaves.
To illustrate the problem, I generate a 10-cycle 2kHz wave, play it out through my MacBook's speakers and pick it up on my iPod Touch:
The echoes are about half the amplitude of the probing signal.
HotPaw pointed out to me in a comment on a recent question that there is a potential problem with dead-spots: regions of destructive interference.
If I use a particular carrier frequency, transmitting from one point in the room to another, there will be certain locations where acoustic cancellation / destructive interference occurs, resulting in a dead spot.
Surely other technologies such as Wi-Fi must encounter the same difficulties. How do engineers deal with this phenomenon?
The only solution I can think of is to simultaneously use say three different carriers, and have the listener select the strongest.
PS severely hampered on the tags: data transmission, communication, radio, information transfer, echo, Radio, rf, signal, bleh