Abstract: An apparatus that automatically adjusts self-noise and can lower the lower limit value of a measurement range by reducing the effects of self-noise on measured values. This apparatus corrects self-noise when amplifying an output signal from a sensor so as to conform to a sensor sensitivity G, further processing the amplified signal, and then outputting the processed signal as a measured value. This apparatus includes a sensor sensitivity adjusting circuit that adjusts an amplification factor so as to conform to the sensor sensitivity G, a self-noise value calculating circuit 4 that calculates a self-noise component F·N from the amplification factor adjusted by the sensor sensitivity adjusting circuit so as to conform to the sensor sensitivity G, and a measured value correcting circuit that calculates a true measured value F·S from the self-noise component F·N calculated by the self-noise value calculating circuit 4 as well as a measured value L containing the self-noise component F·N.

Abstract: The present invention provides an apparatus that automatically adjusts self-noise which apparatus can lower the lower limit value of a measurement range by reducing the effects of self-noise on measured values. This apparatus corrects self-noise when amplifying an output signal from a sensor 1 so as to conform to a sensor sensitivity G, further processing the amplified signal, and then outputting the processed signal as a measured value.