| 摘要 |
PURPOSE:To input an input radio wave by connecting the primary coil of the 1st magnetic circuit in series with a voltage detecting coil of the 2nd magnetic circuit so as to form a voltage drop coil and extracting a difference of effective voltage generated between the secondary coil of the 1st magnetic circuit and the voltage drop coil. CONSTITUTION:The primary coil L1 of the 1st magnetic circuit 1 and the voltage detecting coil Ls of the 2nd magnetic circuit 2 are connected between a signal input point X and ground in series to form a voltage drop coil LD. Since an AGC signal is increased when an input signal is larger, a DC voltage given to a DC control coil LDC1 via an inversely proportional amplifier circuit 3 is lower and a voltage generated in the secondary coil L2 is higher. Since a DC voltage given to a DC control coil LDC2 via a proportional amplifier circuit 4 is higher in the 2nd magnetic circuit 2, the inductance of the voltage detecting coil LS is smaller, and a voltage generated in the voltage detecting coil LS is lower. Thus, a large input signal is suppressed. |
