Nec Corporation

Nec Compound Semiconductor Devices, Ltd.

Gary Hau

Naotaka Iwata

In a predistortion type linearizer including a FET, an input matching circuit connected to the drain of the FET for receiving an input signal, an output matching circuit connected to the source of said the FET for outputting an output signal, and a inductor having a first terminal connected to the gate of the FET and a second terminal for receiving a first control voltage, a variable impedance circuit is connected to the second terminal of the inductor, and the impedance of the variable impedance circuit is adjusted by a second control voltage.

Predistortion type linearizer controlled by two control voltages

A linear power amplifier includes a driver stage, employing an active feedforward-type predistorter, connected in cascade with a final power stage. The active feedforward-type predistorter has an amplifier with a predistorter connecting between its input and output. This driver stage has opposite gain and phase characteristics to that of the final power stage and is used to predistort an input signal. When combined with the final power stage, the nonlinear gain and phase of the power stage are compensated and linearized by the driver stage, resulting in a linear power amplifier with low distortion amplification and high efficiency operation.

Linearized power amplifier based on active feedforward-type predistortion

This invention relates to an electronic circuit (predistortion type linearizer) for linearizing the nonlinear responses of amplifiers, to achieve low distortion, wide-dynamic range amplification particularly suitable for cellular handsets application.

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Tokyo, Japan

Gary Hau