The cochlea, or inner ear, inspired the design of a fast, ultra-broadband, low-power radio chip. Rahul Sarpeshkar, associate professor of electrical engineering and computer science at Massachusetts Institute of Technology, and his graduate student, Soumyajit Mandal, dissected the workings of the human ear. Sarpeshkar said, "The more I started to look at the ear, the more I realized it’s like a super radio with 3,500 parallel channels."
Their “RF cochlea” chip mimics the structure and function of the biological cochlea which uses fluid mechanics, piezoelectrics and neural signal processing to convert sound waves into electrical signals that are routed to the brain.
The RF cochlea is embedded on a small silicon chip which is attached to an antenna. It works as an analog spectrum analyzer, picking up electromagnetic waves which travel through electronic inductors and capacitors to electronic transistors, much like the fluid, membrane, and hair cells in the human cochlea translate sound into electric signals the brain can understand.
Their device is faster than any other RF spectrum analyzer and consumes about 100 times less power. The chip could become part of a radio which could receive a broad range of frequencies and differentiate between them. The device can perceive radio signals at very high frequencies such as used by most commercial wireless applications.
Sarpeshkar’s group has been taking inspiration from the human body at MIT’s Research Laboratory of Electronics for some time. Previously, the human vocal tract became their model for an analog speech-synthesis chip which could be used for speech recognition and voice identification.
The two researchers have filed for a patent to incorporate their RF cochlea in a universal or software radio architecture designed to efficiently process a broad spectrum of signals including cellular phone, wireless Internet, FM, and TV.
Sarpeshkar blends biology with electronics in his research. He explains, “The work provides an analysis of why cochlear spectrum analysis is faster than any known spectrum-analysis algorithm. Thus, it sheds light on the mechanism of hearing as well.” A Renaissance man, Sarpeshkar mixes life with technology. He would surely find the following Haiku poem written by a child as having relevance to his work:
Green trees blow as the
wind is whispering in my
ear with nature’s music.