| 摘要 |
PROBLEM TO BE SOLVED: To adaptively control a step size parameter of an adaptive equalizer in a digital signal processor in accordance with a SOP variation speed.SOLUTION: A digital coherent receiver comprises an adaptive equalizer, a SOP variation speed computer, and a step size parameter control processor. The adaptive equalizer compensates for waveform distortion of a digital signal s0 under adaptive equalization control. In the SOP variation speed computer, a stokes parameter representing a state of polarization SOP of the digital signal s0 is computed from a tap coefficient of the adaptive equalizer, and a SOP variation speed ω0 at arbitrary time intervals is computed using the stokes parameter and outputted. In the step size parameter control processor, a step size parameter μ0 which is multiplied in updating the tap coefficient of the adaptive equalizer, is controlled adaptively in accordance with the SOP variation speed ω0 and set to the adaptive equalizer. |
