| 摘要 |
PURPOSE:To output the signal of good quality regardless of the electric field strength, by suitably controlling the attenuation of the attenuation circuit provided at the input and output side of the amplifying circuit with one varying means. CONSTITUTION:The high frequency signal incoming to the input terminal 4 via the feeding line 2a from the antenna 1 is outputted to the output terminal 5 via the first attenuation circuit 6, amplifying circuit 7 and second attenuation circuit 8 and fed to the television receiver 14 via the feeding line 2b. The impedance of the diodes D1,D2 connected in each attenuation circuit is mutually controlled to reverse direction depending on the change in the voltage value appeared at the control terminals 9a,9b with the operation of one variable resistor VR1. That is, when the knob 10' is selected to the weak position, the incoming high frequency signal is mainly attenuated at the attenuation circuit 8 at the output side, and if the knob 10' is selected to the strong position, and incoming high frequency signal is mainly attenuated at the attenuation circuit 6 at the input side. |
