HIGH FREQUENCY AMPLIFIER CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a high frequency amplifier circuit capable of suppressing gain fluctuation due to variation in input power to improve linearity.

SOLUTION: Amplifiers 24, 26 amplify a wide area modulation signal distributed into two by a distributor 12. A bias circuit 34 impresses fixed bias voltage to an input terminal of the amplifier 24. A bias circuit 36 adjusts bias voltage impressed on an input terminal of the amplifier 26 so that bias current is converged to a fixed value by a predetermined time coefficient to fluctuation of the bias current in an output terminal of the amplifier 26. The time constant here is set to a value sufficiently larger than an inverse number of bandwidth of a wide area modulation signal.

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