A COMPUTER chip modelled on the human ear could be used in universal receivers for radio-frequency signals ranging from cellphone and wireless internet transmissions to radio and television broadcasts.
Devices such as cellphones or FM radios are generally tuned to only a narrow frequency band. The new device is inspired by the network of hairs in the inner ear, which can pick up a wide range of sound frequencies.
We can hear because sound waves make the eardrum vibrate, which creates waves in the fluid-filled inner ear. Hairs on the membrane inside the inner ear are moved by these waves, and because different hairs respond to different frequencies, signals from the hair cells enable the brain to work out the frequency of the sound.
Massachusetts Institute of Technology researchers mimicked this process within a chip that creates an electromagnetic wave in response to radio frequencies. The wave activates a network of transistors that act like hair cells in the ear to reveal the wave's frequency (IEEE Journal of Solid State Circuits, Previous universal digital receivers have required 100 times the power of the single-frequency receivers now in use. But the ear-based analogue version, which can process frequencies ranging from 600 megahertz to 8 gigahertz, draws no more electricity than single-frequency receivers.
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