| 摘要 |
PURPOSE: A portable radio transceiver is provided to obtain optimum operating efficiency by permitting both the RFPA and audio PA to amplify linear signals and controlling the supply voltage in correspondence with the envelope. CONSTITUTION: A portable radio transceiver(100) comprises a radio frequency power amplifier(RFPA)(102) for amplifying a signal to be transmitted, such as a radio frequency signal provided by a modulator(104). The modulator modulates an audio signal produced at a microphone(106), which is to be transmitted. The power to the RFPA is provided by a shared power regulator or power source(108), which regulates voltage provided by a battery(109). The RFPA is connected to an antenna switch(112) which alternatively couples an antenna(114) with the transmit path or the receive path. The receive path includes a demodulator(116) which demodulates a received radio signal, and provides an audio signal on line(118). The audio signal is fed to an audio amplifier(110) which is used for amplifying the audio signal to a level sufficient that it is capable of hearing at a distance from a first speaker(120). A second audio amplifier(122) is used to amplify the audio signal for near distance use, such as an earpiece(124). The received audio signal has an audio signal envelope, which corresponds to the audio amplifier power demand during operation.
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