| 摘要 |
PURPOSE: To compensate a phase characteristic of an amplifier changing non- monotonously with respect to an RF input level by adding a distortion generating route connecting an amplifier and a phase change device after a variable attenuator to a conventional linearizer and revising a fixed resistor attenuator before a linear amplifier into a variable attenuator. CONSTITUTION: Since amplifiers 3, 7, 10 all operates in the linear region when an RF input level is sufficiently low, the gain vectors of routesα,βin the linear and nonlinear amplifier route show prescribed values with respect to a change in the RF input level. On the other hand, as the RF level increases, since only the amplifier 7 operates in the linear region, the routeαis decreased as the RF input level increases and the phase of the resultant vector C' is changed. When the RF input level is further increased, since the amplifier 10 operates also in the nonlinear region, the gain vectors of the routesα,βare both decreased and the phase of the resultant vector C" is further changed. Thus, a linearizer with a non-monotonous phase characteristic with respect to the RF input level change is realized.
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