| 摘要 |
PURPOSE:To eliminate a noise component and an external disturbance light component by providing a photodetector receiving an input signal and a noise signal, a photodetector where an interruption object through which a noise signal passes and an input signal is interrupted is arranged on the front face and an amplifier circuit amplifying signals deferentially from the two photodetectors. CONSTITUTION:When an input signal Vin is received by a 1st photodetector 13 and a 2nd photodetector 15, an external electric noise or a noise from the inside of the detector is received as a noise signal Vn. Moreover, the 2nd photodetector 15 eliminates the input signal Vin by the interruption object 14 and receives only the noise signal. Thus, an output signal from the 1st photodetector 13 and an output signal from the 2nd photodetector 15 are amplified deferentially by an amplifier 2, thereby outputting a signal with the noise signal due to noise eliminated thereof. |
