| 摘要 |
PROBLEM TO BE SOLVED: To provide a transmission circuit in which effect of a reflected wave on a power amplifier can be reduced while reducing power consumption. SOLUTION: The transmission circuit comprises a power amplifier circuit 20, a directional coupler 24 having an input terminal 24a for inputting an amplified transmission signal, an output terminal 24b for outputting the transmission signal to the antenna side, a terminal 24c for detecting the travelling-wave of the transmission signal, and a terminal 24d for detecting the reflected wave of the transmission signal, a travelling-wave AC/DC conversion circuit 27 connected with the travelling-wave detection terminal 24c, a reflected wave AC/DC conversion circuit 28 connected with the reflected wave detection terminal 24d, an FET 11 having a current path connected with the output of the travelling-wave AC/DC conversion circuit 27 and a gate connected with the output of the reflected wave AC/DC conversion circuit 28, and a control circuit 10 having a capacitor 14 connected between one end of the FET 11 and a joint 19, a capacitor 15 connected between the other end of the FET 11 and the earth, and a first resistive element 12 connected in parallel with the current path of the FET 11. COPYRIGHT: (C)2005,JPO&NCIPI
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