Patent ID: 6501730
Filing Date: 2002-12-31
Classification: H04L

Abstract:
A receiver with a demodulator comprising a A/D converter for converting a reception analog signal to a digital signal, a I/Q detector for deriving I/Q data from the digital signal, a discrete-Fourier-transformer for discrete-Fourier-transforming the derived I/Q data, and a delay-detector for detecting the discrete-Fourier-transformed data,CHARACTERIZED BY first frequency offset detecting means (7) for detecting a frequency offset value of an input signal to the demodulator in accordance with a phase reference symbol contained in the discrete-Fourier-transformed data; second frequency offset detecting means (8) for detecting a frequency offset value of the input signal to the demodulator in accordance with a phase difference of the delay-detected signal; an integrator (17) for integrating the frequency offset value detected by said first frequency offset detecting means; and selecting means (10) for comparing an output of said integrator with a predetermined first range of threshold values, selecting the frequency offset value detected by said second frequency offset detecting means if the output of said integrator is in the first threshold value range, and selecting the frequency offset value detected by said first frequency offset detecting means if the output of said integrator is not in the first threshold value range, wherein automatic frequency control is performed in accordance with the frequency offset value selected by said selecting means.