The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 25, 2024
Filed:
May. 27, 2020
Nippon Telegraph and Telephone Corporation, Tokyo, JP;
Ryo Igarashi, Musashino, JP;
NIPPON TELEGRAPH AND TELEPHONE CORPORATION, Tokyo, JP;
Abstract
An optical reception apparatus includes an optical coherent reception unit that generates an I-axis component of a reception signal and a Q-axis component of the reception signal based on an optical signal subjected to continuous phase frequency shift keying, a conversion unit that generates a digital signal of the I-axis component of the reception signal and a digital signal of the Q-axis component of the reception signal, a differential detection unit that generates a differential detection signal, a frequency offset compensation unit that derives a phase change amount or a temporal change in the Q-axis component of the differential detection signal whose component of a frequency offset has been compensated, a clock error detection unit that detects an amount of shift of a sampling phase of the differential detection signal whose component of the frequency offset has been compensated, based on the phase change amount or the temporal change in the Q-axis component of the differential detection signal, and a reception clock generation unit that generates the clock at a frequency adjusted such that the amount of shift becomes small.