Patent ID: 7839942

Claim:
A demodulator comprising: a plurality of demodulation modules, each receiving an OFDM signal in which a symbol interval consists of a guard interval and a valid symbol interval and demodulating the OFDM signal to extract symbol data, and a combiner for combining the demodulated data output from the plurality of demodulation modules and generating combined demodulated data, wherein each of the plurality of the demodulation modules comprises: an AGC unit for generating an AGC control signal for adjusting a magnitude of the received signal to specific level; and a correlation detector for detecting a correlation between a complex-valued baseband OFDM signal that has been gain-adjusted by the AGC unit and a signal obtained by delaying the complex-valued baseband OFDM signal by one valid symbol interval to generate a correlation waveform signal representing the detected correlation; the demodulator further comprising a correlation combiner that generates a combined correlation signal by combining the correlation waveform signals output from the correlation detectors in the plurality of demodulation modules; the correlation combiner multiplying the correlation waveform signals by coefficients calculated from gain values represented by the AGC control signals output from the respective AGC units in the plurality of demodulation modules and adding the resulting products together to generate the combined correlation signal.