| 摘要 |
PROBLEM TO BE SOLVED: To provide the device of small-scale circuit which optimizes a power efficiency of a power amplifier. SOLUTION: A bias voltage control unit 2 calculates the output power of a PA 8 on the basis of a TPC signal and determines a bias voltage which should be applied to bias tees 7-1 and 7-2 in order to maximize the power efficiency of the PA 8. The bias voltage control unit 2 gives an instruction to duty varying circuits 5-1 and 5-2 to vary a duty cycle of frequency division signals of transmission frequency signals generated by frequency dividing circuits 6-1 and 6-2, and gives them to DC-DC converters 4-1 and 4-2 as a driving signal. DC-DC converters 4-1 and 4-2 convert a voltage of a power source 3 to the voltage in accordance with the driving signals and apply them to the bias tees 7-1 and 7-2. Thus, the output power of the PA 8 is controlled. COPYRIGHT: (C)2006,JPO&NCIPI |
