| 摘要 |
PROBLEM TO BE SOLVED: To provide a transmitter of an EER (envelope elimination and restoration) method with wide band and high efficiency. SOLUTION: Amplitude components of a modulation signal are inputted in a power supply terminal of a high frequency power amplifier 130, an IQ quadrature signal is inputted in a high frequency input terminal of the high frequency power amplifier 130 and an original modulation signal is obtained from the output of the high frequency power amplifier 130. Collector voltage is supplied from a group 615 of DC-DC converters with successively different output voltage to an emitter follower 729 via a group 621 of switches. As for the collector voltage, efficiency of the emitter follower 729 is enhanced by reducing difference between emitter voltage of the emitter follower 729 and collector voltage of the emitter follower 729 by selecting any one output of DC-DC converters 616 to 620 by the group 621 of switches corresponding to the level of the amplitude components and giving the output to the emitter follower and a wide band operation is made possible by performing voltage conversion of power voltage of the high frequency power amplifier 130 by the emitter follower 729. COPYRIGHT: (C)2004,JPO
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