| 摘要 |
PURPOSE:To amplify waves in common with an identical amplifier to the two waves having a large level difference by adding a nonlinear distortion reduction circuit and its operation control circuit to the input side of a low level signal and using a supervisory signal at the output side of an amplifier so as to control the operation of the nonlinear distortion reduction circuit. CONSTITUTION:In amplifying in common a TDMA signal as a high level signal and an FM signal as a low level signal, two waves in total, when two input signal waves are given respectively to input terminals 1 and 2, if a burst signal of the TDMA signal at the terminal 1 exists, the input signal level of an amplifier 6 is sufficiently high and the amplifier is operated nearly in a saturated level. A pre-distortion nonlinear distortion reduction circuit 3 exists in an input path from the terminal 2, a nonlinear distortion having opposite nonlinearity to that of the amplifier 6 is generated in advance is generated by using the circuit 3, and after the distortion is fed to the substantial FM signal, the result is fed to the amplifier 6. Thus, the nonlinearity characteristic of the reduction circuit 3 and the amplifier 6 is cancelled and the FM signal output appearing at an output terminal 8 is nearly identical to that amplified singly by the linear amplifier 6.
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