With Ashoke Ravi's help, future cell phones and netbooks won't need separate circuits to transmit multiple radio signals (over a cellular network, Wi-Fi, and WiMax, for example); a single transmitter will handle them all.

Radios that use software to receive signals over different wireless protocols exist already, but progress has lagged on the transmission side. Much of the difficulty has involved building amplifiers that can cope with the different power levels needed to transmit over the varied distances typical of different wireless networks.

Ravi, a researcher at Intel, built a software-controlled transmitter that solves the problem. Instead of changing the power level to transmit different signals, its amplifier can attenuate or boost the outgoing signal by combining the output of two oscillators that operate at a constant power level. His design allows the amplifier to be optimized for a single power level, increasing battery life.

Ravi expects devices incorporating the technology, such as laptops capable of switching seamlessly between 3G and Wi-Fi networks, to be on the shelves within five years. --Stephen Cass