| 摘要 |
Apparatus and method for providing a radio frequency output to promote higher amplifier efficiencies is described herein. The apparatus includes driver means having a driver output for providing an amplified radio frequency signal and switching means in communication with the driver output of the driver means. The switching means directs the amplified radio frequency signal to a first or a second circuit path connectable to the driver output of the driver means. The first circuit path provides a low power level output of the radio frequency signal, and the second circuit path provides a high power level output of the radio frequency signal. In the low power level mode, the power amplifier in the output stage is switched out of the circuit path. The method includes the steps of supplying a modulated signal from a driver stage which includes at least one radio frequency amplifier, determining the transmission power requirements of the modulated signal, selecting one of a plurality of output stages in accordance with the transmission power requirements, and switching the modulated signal to the selected output stage to supply the output of the selected output stage to an antenna.
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