| 摘要 |
PROBLEM TO BE SOLVED: To provide a transmission circuit that protects a power amplifier by limiting power output to preset valve even when a transmission setting voltage is changed and shorten the time until the transmission power is converged to a set transmission power in addition to giving no disturbance onto other receivers. SOLUTION: The transmission circuit is provided with: a power amplifier 5 subjected to gain control; a detection section 10 for detecting a transmission signal outputted from the power amplifier 5 and outputting a detection voltage corresponding to its level; and a gain control section 7 for comparing the detected voltage with a transmission power setting voltage to set the level of the transmission signal outputted from the power amplifier 5 and applying a gain control voltage to the power amplifier 5, and the transmission power setting voltage is given to the gain control section 7 via a low pass filter 9. COPYRIGHT: (C)2004,JPO
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