| 摘要 |
PROBLEM TO BE SOLVED: To provide a frequency offset estimation circuit and a frequency offset estimation method having high noise resistance.SOLUTION: The frequency offset estimation circuit includes: a phase difference detector which in order to estimate frequency offset expressing a difference between a carrier frequency of a received optical signal and a frequency of a locally generated light to be used for reproducing a transmission signal from the received optical signal, detects a phase difference generated between a first symbol and a second symbol due to the frequency offset on the basis of a phase of the first symbol and a phase of the second symbol located on a position separated from the first symbol only by a specified symbol internal; an estimator for estimating the frequency offset on the basis of the phase difference detected by the phase difference detector; and a symbol interval control part for specifying a symbol interval on the basis of the frequency offset estimated by the estimator. |
