WAVELENGTH DISPERSION ESTIMATION CIRCUIT, OPTICAL RECEIVER, AND WAVELENGTH DISPERSION ESTIMATION METHOD

摘要

A Fourier-transformer (11) performs Fourier transform on a filter coefficient output from an adaptive equalizer (6) which comprises a finite impulse response filter of N taps (N represents an integer of 2 or more) in a time direction. An eigenvalue sum calculator (15) integrates a frequency-differentiation result of the Fourier-transformed filter coefficient and a complex conjugate of the Fourier-transformed filter coefficient to calculate a matrix, and calculates a sum of two eigenvalues of the matrix. A proportionality factor calculator (14) calculates a proportionality factor for frequency from the sum of the two eigenvalues.