Post by lab~rat >:-)On Sat, 06 Oct 2007 04:14:55 GMT, Dave Oldridge
Post by Dave OldridgePost by lab~rat >:-)On Fri, 05 Oct 2007 08:11:04 GMT, Dave Oldridge
Post by Dave OldridgePost by lab~rat >:-)If she only had one bionic ear, she wouldn't be able to tell what
direction distant sounds were coming from. FACT.
NOT fact. If the ear is moved and the software (brain) learns to read
the phase changes, it can work. We do it all the time in radio by
moving a virtual antenna in a circle and demodulating the phase
modulation that the motion imposes on the signal, comparing it against
the signal driving the motion.
It is a fact. If you're standing in a large area and only have one
ear to use, you can't tell the direction that it's coming from.
Unless you move your head around a bit while listening. As long as you
stand still you won't have a clue. Takes a while to compensate, if
you've just lost hearing in one ear, though.
It takes forever.
Not in my case. But it still required movement to place a sound. If I
was just sitting perfectly still in my chair and something happened
outside, it could seem to be inside until I moved my head. Of course the
longer and more sustained the sound, the easier it is to locate.
The principle is used in modern radio direction finders for VHF and UHF
signals. The virtual antenna is moved in a circle of known parameters
and the phase of the incoming signal is compared with the position of the
antenna in its circle. The result is an accurate direction fix within
25ms. The human brain is a good deal more complex than the antenna-moving
apparatus and doesn't need an exact or regular circle. The key
requirement is that the hardware moving the ear know where it moved it.
It then becomes possible to locate the source, even with one ear (but
slower than with two, obviously). Now a bionic ear could be constructed
to report a lot more things about the incoming sound, including tiny
phase shifts, which could be wired to give the brain (once it learned to
interpret the signals).
--
Dave Oldridge+
ICQ 1800667