LIGHT RECEIVING CIRCUIT FOR OPTICAL FREE-SPACE TRANSMISSION

摘要

PROBLEM TO BE SOLVED: To provide the light receiving circuit for optical free-space transmission with an excellent S/N ratio characteristic without causing DC saturation under an external disturbance noise light including a DC component. SOLUTION: A current-voltage converter inverted amplifier 4 of a light receiving circuit is provided with a signal feedback section 11 that has a low impedance characteristic at a signal frequency band of a transmission object and a high impedance characteristic at a higher frequency band than the signal frequency band and with a DC feedback section 12 that has a low impedance characteristic at a lower frequency band than the signal frequency band so as to realize a high S/N without provision of a signal band-pass filter at a post-stage of the current-voltage converter inverted amplifier 4.