OPTICAL SIGNAL RECEIVING APPARATUS

摘要

PURPOSE: To provide an optical signal receiving apparatus which can easily demodulate information taken in optical signals at high SN ratio even in a high frequency band. CONSTITUTION: Electric signals with a first frequency sent out of a transmitter are supplied to a photoconductive light receiving apparatus 100 through a voltage applying part 200. In this state, in the case the photoconductive light receiving apparatus 100 receives photo signals, current signals corresponding to the values of the products of voltage signals and photo signals are generated in the photoconductive light receiving apparatus 100. The current signals generated in this way are sent to a frequency selecting apparatus 500 and components in a frequency band with a prescribed frequency width are selected and sent out while the frequency of the difference of a first frequency and a second frequency being utilized as a center. The signals with selected frequency are demodulated by demodulating part 700.