A True Artificial Cochlea
Constructed by engineers at MIT, a single low power radio receiver chip has been painstakingly modelled on the function and deciphering capabilities of the human ear.
Rahul Sarpeshkar, associate professor of electrical engineering and computer science, and his graduate student, Soumyajit Mandal, designed the chip to mimic the cochlea. They felt it had done such a good job, they have actually named it the "radio frequency (RF) cochlea".
"The cochlea quickly gets the big picture of what's going on in the sound spectrum," said Sarpeshkar. "The more I started to look at the ear, the more I realized it's like a super radio with 3,500 parallel channels."
"Somebody who works in radio would never think of this, and somebody who works in hearing would never think of it, but when you put the two together, each one provides insight into the other."
A human cochlea is a mix of fluid mechanics, piezoelectrics and neural signal processing to convert sound waves into electrical code. It was relatively straightforward to duplicate the process technologically, when approached from that angle. Using electronic inductors and capacitors, the exact same principles are involved, but concentrating on a much higher frequency of spectrum.
This approach is two orders of magnitude more efficient than any previous attempt to create a RF spectrum analyzer. In addition, it is only 1.5mm by 3mm in total size.
Circuits for an RF Cochlea (original paper) (PDF)