SAMPLE INTERVAL SYNCHRONOUS POSITION NOTIFICATION DEVICE, OPTICAL RECEIVER AND SAMPLE INTERVAL SYNCHRONOUS POSITION NOTIFICATION METHOD
A sample interval synchronized position notification device includes: a tap coefficient acquisition unit configured to acquire a tap coefficient from an adaptive equalization unit which is configured to perform adaptive equalization of a signal; a group delay calculation unit configured to calculate a group delay based on the tap coefficient; and a shift amount calculation unit configured to calculate a shift amount based on the group delay.
1 . A sample interval synchronized position notification device, comprising:
a tap coefficient acquirer unit configured to acquire a tap coefficient from an adaptive equalization unit which is configured to perform adaptive equalization of a signal;
a group delay calculator configured to calculate a group delay based on the tap coefficient; and
a shift amount calculator configured to calculate a shift amount based on the group delay.
2 . The sample interval synchronized position notification device according to claim 1 , wherein the group delay calculator s configured to:
perform a discrete Fourier transform on the tap coefficient; and
calculate the group delay using the discrete Fourier transform results.
3 . The sample interval synchronized position notification device according to claim 1 , wherein the group delay calculator is configured to:
calculate the group delay by calculation based on a rotator of a discrete Fourier transform matrix and a frequency component of one-fourth of a sampling rate.
4 . The sample interval synchronized position notification device according to claim 1 , wherein the group delay calculator is configured to:
perform a discrete Fourier transform on the tap coefficient and calculate a matrix whose elements are the discrete Fourier transform results;
calculate a PMD operator based on the matrix; and
calculate the group delay by calculating an eigenvalue of the PMD operator.
5 . An optical receiver, comprising:
the sample interval synchronized position notification device according to claim 1 ;
an adaptive equalizer configured to adaptively equalize a signal based on the tap coefficient;
a sampling phase synchronizer configured to synchronize a sample position of the received signal at a sample period based on the shift amount.
6 . A sample interval synchronized position notification method, comprising:
acquiring a tap coefficient from an adaptive equalization unit which is configured to perform adaptive equalization of a signal;
calculating a group delay based on the tap coefficient; and
calculating a shift amount based on the group delay.