Rahul Sarpeshkar, associate professor of electrical engineering and computer science at MIT, and his graduate student, Soumya-jit Mandal, designed the chip to mimic the inner ear, or cochlea. They have built a fast, ultra-broadband, low-power radio chip, modeled on the human inner ear that could enable wireless devices capable of receiving cell phone, Internet, radio and television signals. The chip is faster than any human-designed radio-frequency spectrum analyzer and also operates at much lower power.

The RF cochlea 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 sent to the brain. As sound waves enter the cochlea, they create mechanical waves in the cochlear membrane and the fluid of the inner ear, activating hair cells (cells that cause electrical signals to be sent to the brain). The cochlea can perceive a 100-fold range of frequencies — in humans, from 100 to 10,000 Hz. Sarpeshkar used the same design principles in the RF cochlea to create a device that can perceive signals at million-fold higher frequencies, which includes radio signals for most commercial wireless applications. The RF cochlea, embedded on a silicon chip measuring 1.5 mm by 3 mm, works as an analog spectrum analyzer.

Sarpeshkar and his students describe their new chip in a paper to be published in the June/July issue of the IEEE Journal of Solid-State Circuits. They have also filed for a patent to incorporate the RF cochlea in a universal or software radio architecture that is designed to efficiently process a broad spectrum of signals including cellular phone, wireless Internet, FM, and other signals.

By Vasil Sidorov on April 20, 2009     after MIT Tech Talk