OPTICAL RECEIVING APPARATUS AND DIGITAL RECEIVING CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide an optical receiving apparatus and a digital receiving circuit which ensures high-accuracy digital conversion.

SOLUTION: A local oscillator 110, a 90-degree phase hybrid circuit 120 and an photoelectric conversion units 131 and 132 convert received signal light into electrical signals that indicate a complex electric field of the received signal light. A self-running sampling trigger source 140 oscillates a clock signal that has a frequency preset based on a frequency of the signal light. ADCs 151 and 152 perform sampling at the frequency of the clock signal oscillated by the self-running sampling trigger source 140 for an electrical signal converted by the local oscillator 110, the 90-degree phase hybrid circuit 120 and the photoelectric conversion units 131 and 132 to convert the electrical signal into a digital signal. A demodulating section 164 demodulates the digital signal converted by the ADCs 151 and 152.

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