| 摘要 |
PROBLEM TO BE SOLVED: To provide a portable telephone set which achieves to lower voltage to be supplied a power amplifier (PA) in a low mode than before without causing fluttering in supply switching control of supply voltage to the PA. SOLUTION: During a DC/DC converter 12 supplies voltage C to a PA 16, when a control part 5 controls a gain of a variable gain amplifier (VGA) 15 so that a desired transmission power level becomes lower than a threshold value E for a fixed time interval (a time point shown by an indication line 41), the supply voltage to the PA 16 is switched from C to F. During the DC/DC converter 12 supplies voltage D to the PA 16, when the control part 5 controls the gain of the VGA 15 so that a desired transmission power level may become more than the threshold value E (at a time point shown by an indication line 42), the supply voltage to the PA 16 is controlled to switch from F to C. COPYRIGHT: (C)2011,JPO&INPIT
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