| 摘要 |
A gain-control-type transistor power amplifier is provided which performs gain control in a state in which there is satisfactory linearity by extending the varying range of a gain control voltage capable of controlling the output level of an RF signal. The gain-control-type transistor power amplifier includes an amplifying transistor, to the base of which a bias voltage and an amplification signal are supplied, and a control transistor, to the base of which a gain control voltage is supplied. The gain control voltage output from the emitter of the control transistor is supplied to the base of the amplifying transistor in such a manner as to be superposed onto the base bias, and the base bias voltage is varied by the supplied gain control voltage, controlling the gain of the amplifying transistor and the output level of the RF signal.
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