NOISE ELIMINATING CIRCUIT

摘要

PURPOSE:To eliminate 1/f noise outputted from a solid-state image pickup element by utilizing a reset pulse phiR and a circular phase pulse phiC which are used to set a reference voltage in an element as sample pulses of the output signal of the element. CONSTITUTION:A transistor (TR)8 is in a cutoff state during a period TS wherein a control pulse phiS is at a level L to hold the voltage Vc across a capacitor 13, the emitter voltage of a TR6 becomes VBE lower than the voltage Vo at an output terminal 5, and the collector voltage V1 of a TR8 becomes further Vc lower. The output Vo at the terminal 5 varies from VRESET to VSIG during signal output with regard to its DC level, so V1=(VSIG-VRESET)+VGL is derived. Assuming that the noise component does not vary in one period, then V1= VCL-S is derived and the varying noise component N is eliminated to obtain only a signal component N.