| 摘要 |
PURPOSE:To make stable the non-linear type compensation characteristics automatically, by detecting the distortion noise at the output terminal of compensated amplifier and automatically controlling the non-linear form of amplitude and phase of the nonlinear type compensation circuit so that the level can be minimized. CONSTITUTION:The band block filter 2 sufficiently rejects the noise component of specific narrow band so that the information signal in the transmission signal band is not present beforehand. Next, by using the nonlinear type distortion detector 12 provided at the output of the compensated amplifier 9, the distortion noise of nonlinear form which is fallen in the band is detected. Further, the amplitude and phase of the third order mutual modulation distortion noise put in with the predistortion non-linear type compensation circuit 14 are automatically controlled with the nonlinear type characteristic controller 13 so that the detected distortion noise can be minimized. Thus, the nonlinearity of the amplifier 9 can be compensated with highly stable state. |
