Patent ID: 6310513
Filing Date: 2001-10-30
Classification: H03D,H04L

Abstract:
A demodulator for demodulating a modulation signal which has been modulated by means of quadrature modulation, comprising:a quasi-coherent detection means for executing quasi-coherent detection to the modulation signal and thereby outputting quadrature components;a demodulation means for correcting amplitude errors of the quadrature components outputted by the quasi-coherent detection means, correcting frequency offset components and phase offset components of the quadrature components, and thereby outputting demodulated signals;a signal error detection means for detecting signal errors and polarities of the demodulated signals;a phase error detection means for generating a phase error based on the signal errors and the polarities, for use by the demodulation means;a quadrature error detection means for generating a quadrature error using at least the signal errors; anda quadrature error elimination means, coupled between the quasi-coherent detection means and the demodulation means, for executing complex multiplication to the quadrature components outputted by the quasi-coherent detection means based on the quadrature error generated by the quadrature error detection means and thereby eliminating the quadrature error in the demodulated signals.