| 摘要 |
PURPOSE:To obtain the limiter without waveform distortion by providing a reference potential obtained by a rectified input signal to a signal processing circuit comparing the products between an output potential and the reference potential and between an input potential and the reference potential and using the circuit for a feedback circuit of an operational amplifier. CONSTITUTION:A 1st signal processing circuit 11 and a 2nd processing circuit 12 have the relation of (I1-I2)=(V1-V2).(VG1-VG2), where 11, 12 are currents at 1st and 2nd output terminals O1, O2, and V1, V2, VG1, VG2 are sets of potential at 1st, 2nd input terminals IN1, IN2 and 3rd and 4th input terminals G1, G2. The V2, VG1 are selected to be, e.g. ground potential. A rectifier circuit 14 rectifies and smoothes an input signal VIN to be a DC voltage VRECT which is proportional to the input signal VIN and fed to a 4th input terminal G2 of a 2nd signal processing circuit 12. Since an output VOUT of the operational amplifier 13 is fed back to the operational amplifier 13 via the 2nd signal processing circuit 12, the input to the operational amplifier 13 is in an imaginary grounding state. Thus, the relation of Vout=-Vin.Vrecf/Vrect is obtained. |
