Signal processing apparatus, signal processing method and communication system

Abstract

A receiver convolves an impulse response for compensating for frequency characteristics and a complex impulse response for wavelength dispersion compensation with each of a real component and an imaginary component of each polarized wave of a reception signal. For each polarized wave, the receiver performs complex signal processing of multiplying the imaginary component by the imaginary unit, then branching the resulting component, and adding one imaginary component to the real component. For each polarized wave, the receiver uses, as input signals, the real component and the imaginary component of each polarized wave after complex signal processing and the phase conjugates of them. For each polarized wave, the receiver adds a signal obtained by a process in which each of the real component and the imaginary component of each polarized wave is multiplied by a complex impulse response, the resulting components are added, and a phase rotation is applied and a signal obtained by a process in which each of the phase conjugate of the real component and the phase conjugate of the imaginary component of each polarized wave is multiplied by a complex impulse response, the resulting components are added, and an opposite phase rotation is applied, and adds a transmission data bias correction signal.