| 摘要 |
PURPOSE:To improve distortion characteristics by compensating nonlinearity of a main amplifier in an ultra-high frequency amplifier which amplifies an ultra-high frequency signal including an amplitude-modulated component or several carriers. CONSTITUTION:Dotted-line part 11, indicating the microwave Schottky gate GaAs dual gate FET amplifier, constitutes the nonlinear compensator circuit. An amplitude-modulated microwave signal is inputted to input terminal 9; part of it is extracted by directional coupler 10 and envelope-detected and amplified by detection circuit 12 and great part of the microwave signal is sent to dual gate FET amplifier circuit 11. The envelop-detected and amplified signal is applied to 2nd gate 7 of dual gate FET being superposed on a direct-current bias voltage. The output of dual gate FET amplifier 11 is supplied to microwave FET amplifier circuit 13, the main amplifier, and a nonlinearly-compensated output signal is obtained from output terminal 14 of this circuit 13. |
