Stories tagged Rahul Sarpeshka

Jun
21
2009

Inner ear provides secret to better radio reception

Cochlea model for radio reception
Cochlea model for radio receptionCourtesy Welleschik
A group of MIT engineers is looking to the human body for solutions to some of our technological problems. Many of us are discovering that our HDTVs or cell phones won't work without a better antenna.
Rahul Sarpeshkar, and his graduate student, Soumyajit Mandal, realized that the cochlea in our inner ear is like an antenna. In a paper titled "A Bio-Inspired Active Radio-Frequency Silicon Cochlea" (15 pg PDF) they explain that

The biological inner ear or cochlea is an amazing custom analog computer capable of the equivalent of 1GFLOPS of spectral-analysis and gain-control computations with 14uW of power on a 150mV battery and a minimum detectable signal of 0.05 angstroms. It achieves such efficiency because of the clever use of an active nonlinear transmission line implemented with fluids, membranes, active piezoelectret cells, micromechanics, and electrochemistry.The cochlea has an amazingly large input dynamic range of 120dB, analyzes frequencies over a 100-fold range in carrier frequency (100Hz-10kHz), and amplifies signals at 100kHz even though its cells have time constants of 1ms.

Mining the intellectual resources of nature

By modeling the cochlea with analagous electronic components, they created what they call an RF silicon cochlea.

The RF cochlea, embedded on a silicon chip measuring 1.5 mm by 3 mm, works as an analog spectrum analyzer, detecting the composition of any electromagnetic waves within its perception range. Electromagnetic waves travel through electronic inductors and capacitors (analogous to the biological cochlea's fluid and membrane). Electronic transistors play the role of the cochlea's hair cells.

The chip is faster than any human-designed radio-frequency spectrum analyzer and also operates at much lower power.

Looking to nature for technological solutions

This is not the first time Sarpeshkar has drawn on biology for inspiration in designing electronic devices. Clicking this link will direct you to ten papers resulting from bio-inspired projects in sensing and computing.

Source MIT News