| 摘要 |
PROBLEM TO BE SOLVED: To provide a feedforward amplifier wherein the enough suppressive amount of its distortion can be obtained over a wide frequency band. SOLUTION: In the feedforward amplifier, two pilot signals of different frequencies from each other are used as the pilot signals for removing its distortion. In a matching circuit present in an auxiliary amplifier 10, a variable- capacitance element 24 is so provided as to make variable the impedance of the matching circuit. Subsequently, in a control-signal calculating circuit 19, the amplitude-level difference between the two sensed pilot signals is calculated by a subtracter 32. Then, a calculating circuit 33 so calculates a control signal based on the amplitude-level difference between the two pilot signals, and so gives the control signal to the variable-capacitance element 24 as to correct the slope of the amplitude frequency characteristic of the auxiliary amplifier 10.
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