| 摘要 |
PURPOSE:To constitute a circuit, which does not necessitate a wavelength filter, and is constituted of one light receiving element by providing at least three sets of comparators, which compare the detection output signal of the light receiving element and a reference voltage, and outputs a comparison result. CONSTITUTION:The output of the light receiving element 2 is inputted to the comparators 1-1-n, and the comparators 1-1-n receive a threshold voltage from an REF signal block 10, and compare them respectively. A compared and outputted signal 20 is converted into the signal of every wavelength by a signal switch circuit block 11. Thus, because the signal of plural wavelengths can be outputted only using one light receiving element 2, and in addition, the filter is dispensed with, resource economy and cost reduction can be realized. |
