| 摘要 |
<P>PROBLEM TO BE SOLVED: To attain higher power efficiency of PA in a transmission circuit. <P>SOLUTION: The transmission circuit passes a frequency in a predetermined range through a signal output from an amplifier via a directional coupler and extracts a secondary harmonic level from the passing frequency in a predetermined range. Also, the transmission circuit outputs a difference between a set value of an output level of a high-frequency signal and a preset value corresponding to a level difference between a main signal and the high-frequency signal. In addition, the transmission circuit compares the output difference to the secondary harmonic level, and when the secondary harmonic level is larger, controls to increase a power supply voltage of the amplifier and, when the difference is larger, controls to decrease the power supply voltage of the amplifier. <P>COPYRIGHT: (C)2012,JPO&INPIT |
