| 摘要 |
PURPOSE:To prevent the interference between an automatic gain control and an offset compensation control, and to apply the titled amplifier to the continuous signal transmission, too, except burst signal transmission, by executing compensation of an offset voltage and the automatic gain control based on the output signal of a peak level detecting circuit, an identifying circuit, a timer and a pattern detecting circuit. CONSTITUTION:In an offset voltage controlling circuit 14, when an offset control signal S12=1 is inputted, an offset compensating signal S1 which has enlarged an offset compensating voltage Vof to a positive side is outputted and applied to an adding circuit 3, and when S12=0 is inputted, the offset compensating signal S1 which has enlarged the offset compensating voltage Vof to a negative side is outputted and supplied to the adding circuit 3. The adding circuit 3 adds the offset compensating signal S1 to an input signal Si, executes an offset compensation and applied an addition result signal S2 to an amplifier 4. On the other hand, when a gain control signal S13=1 is inputted, a gain controlling circuit 15 outputs a gain variable signal S3 for increasing the gain and supplies it to an amplifier 4, and when S13=0 is inputted, the gain variable signal S3 for decreasing the gain is outputted and supplied to the amplifier 4. In such a way, the amplifier 4 adjusts an amplitude of an output signal So.
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