| 摘要 |
PROBLEM TO BE SOLVED: To prevent a momentary abnormal increase in a transmission output level of an antenna by eliminating instantaneous shut-off at the switching of an attenuator while the control of a wide transmission output level is realized without enlarging a gain variable range of a variable gain amplifier. SOLUTION: A transmitter electric power amplifying unit has a power amplifier 3 for generating electric power to an antenna; and an output branching device 4 for generating output by branching part of the output wherein information of a transmission power level is obtained from the branched output and the variable gain amplifier 2 put between the power amplifier and the input is controlled, so that the transmission output level is maintained at a prescribed value are provided. A pair of attenuators 7, 8, which are non-shut-off type at switching time, are provided between a variable gain controller 2 and the power amplifier 3 and between the output branching device 4 and the variable gain amplifier 2, to shift the attenuation amount differentially in an interlocking way. COPYRIGHT: (C)2005,JPO&NCIPI
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