Many Signals, One Chip

New RF chip mimics inner ear to pick up cell-phone, Internet, radio, and TV signals.

The human ear is a marvel of efficient engineering–using very little energy, it can detect a stunningly broad range of frequencies. Inspired by that prowess, MIT engineers have built a fast, ultrabroadband, low-power radio chip that could be used in wireless devices capable of receiving many different kinds of signals.

Standing by The RF cochlea, a low-power, ultrabroadband radio chip, attaches to an antenna to pick up a wide range of signals.

Rahul Sarpeshkar ‘90, associate professor of electrical engineering and computer science, and his graduate student Soumyajit Mandal, SM ‘04, designed the chip to mimic the inner ear, or cochlea. The chip separates radio signals into their individual frequencies faster than any other human-designed spectrum analyzer and operates at much lower power. Traditional radio chips that could do this would consume too much power to be practical.

“The cochlea quickly gets the big picture of what’s going on in the sound spectrum,” says 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.”

The researchers describe their new chip, which they have dubbed the “radio frequency (RF) cochlea,” in a paper published in the June issue of the IEEE Journal of Solid-State Circuits. They have also filed for a patent for a universal radio architecture that uses the RF cochlea to process a broad spectrum of signals, including those transmitted in most commercial wireless applications.

In the biological cochlea, sound waves are converted to mechanical waves that travel along the cochlear membrane and the fluid of the inner ear, activating hair cells, which send electrical signals to the brain. In the RF cochlea, which is embedded on a silicon chip measuring 1.5 by 3 millimeters, electromagnetic waves travel through electronic inductors and capacitors that imitate the biological fluid and membrane, and electronic transistors play the role of the hair cells. But while the human ear can perceive frequencies from 100 to 10,000 hertz, the RF cochlea’s range extends from 600 megahertz to 8 gigahertz, encompassing cell-phone, Internet, radio, and television signals.

Trained as an engineer but also a student of biology, Sarpeshkar–with his group in MIT’s Research Laboratory of Electronics–often draws on the natural world for inspiration in designing electronic devices. He says engineers can learn a great deal from studying biological systems that have evolved over hundreds of millions of years to perform sensory and motor tasks very efficiently in environments noisy with competing signals.

Though we have a long way to go before our inventions will successfully compete with those in nature, Sarpeshkar says, “we can mine the intellectual resources of nature to create devices useful to humans.

Tech Obsessive?
Become an Insider to get the story behind the story — and before anyone else.

Subscribe today

Uh oh–you've read all of your free articles for this month.

Insider Premium
$179.95/yr US PRICE

Want more award-winning journalism? Subscribe and become an Insider.
  • Insider Premium {! insider.prices.premium !}*

    {! insider.display.menuOptionsLabel !}

    Our award winning magazine, unlimited access to our story archive, special discounts to MIT Technology Review Events, and exclusive content.

    See details+

    What's Included

    Bimonthly magazine delivery and unlimited 24/7 access to MIT Technology Review’s website

    The Download: our daily newsletter of what's important in technology and innovation

    Access to the magazine PDF archive—thousands of articles going back to 1899 at your fingertips

    Special discounts to select partner offerings

    Discount to MIT Technology Review events

    Ad-free web experience

    First Look: exclusive early access to important stories, before they’re available to anyone else

    Insider Conversations: listen in on in-depth calls between our editors and today’s thought leaders

  • Insider Plus {! insider.prices.plus !}* Best Value

    {! insider.display.menuOptionsLabel !}

    Everything included in Insider Basic, plus ad-free web experience, select discounts to partner offerings and MIT Technology Review events

    See details+

    What's Included

    Bimonthly magazine delivery and unlimited 24/7 access to MIT Technology Review’s website

    The Download: our daily newsletter of what's important in technology and innovation

    Access to the magazine PDF archive—thousands of articles going back to 1899 at your fingertips

    Special discounts to select partner offerings

    Discount to MIT Technology Review events

    Ad-free web experience

  • Insider Basic {! insider.prices.basic !}*

    {! insider.display.menuOptionsLabel !}

    Six issues of our award winning magazine and daily delivery of The Download, our newsletter of what’s important in technology and innovation.

    See details+

    What's Included

    Bimonthly magazine delivery and unlimited 24/7 access to MIT Technology Review’s website

    The Download: our daily newsletter of what's important in technology and innovation

/
You've read all of your free articles this month. This is your last free article this month. You've read of free articles this month. or  for unlimited online access.