Patent ID: 6041085
Filing Date: 2000-03-21
Classification: H04L

Abstract:
A carrier regenerating circuit attached to a multi-level orthogonal amplitude demodulator, which compriseslevel-holding means which samples and holds two demodulated signal components at adjoining apertures of eye patterns of said two demodulated signal components to get location information (I0, Q0) and (I1, Q1) on a phase plane of said two demodulated signal components and at a middle point of said adjoining aperture to get additional location information (I1/2, Q1/2) on said phase plane of said two demodulated signal components,frequency deviation calculating means which calculates a semi frequency deviation signal based on deviation of a current locus of said two demodulated signal components from a proper locus of said two demodulated signal components using said location and additional location information (I0, Q0), (I1/2, Q1/2), and (I1, Q1), anda voltage controlled oscillator which regenerates a carrier used by said multi-level orthogonal amplitude demodulator,wherein said voltage controlled oscillator is controlled by said semi frequency deviation signal,wherein automatic frequency control of regenerated carrier is performed.