Patent ID: 7580466

Claim:
A demodulation device comprising: a Fourier transform unit for performing a Fourier transform on a received OFDM signal to output a subcarrier component obtained as a result of the Fourier transform; a pilot signal-extracting unit for extracting a pilot signal contained in said subcarrier component output from said Fourier transform unit; a known signal outputting unit for outputting a known signal corresponding to said pilot signal; a first divider unit for dividing said pilot signal extracted in said pilot signal-extracting unit by said known signal output from said known signal outputting unit to calculate a transmission channel characteristic corresponding to said pilot signal; a delay profile estimation unit for estimating a delay profile based on said transmission channel characteristic of said pilot signal calculated in said first divider unit, and outputting a signal corresponding to a maximum delay time that is an arrival time of a most delayed incoming wave and a signal corresponding to a minimum delay time that is an arrival time of a front most incoming wave in said delay profile estimation; an interpolation filter unit for performing interpolation on said transmission channel characteristic of said pilot signal calculated in said first divider unit along a time axis and along a frequency axis, and outputting a transmission channel characteristic corresponding to said subcarrier component; a timing synchronization unit for outputting a timing signal that controls timing for performing said Fourier transform in said Fourier transform unit according to said signal corresponding to said minimum delay time output from said delay profile estimation unit; and a second divider unit for dividing said subcarrier component output from said Fourier transform unit by said transmission channel characteristic corresponding to said subcarrier component output from said interpolation filter unit, to output a demodulated signal, wherein said Fourier transform unit performs said Fourier transform according to said timing signal; and said interpolation filter unit sets a pass band of a frequency interpolation filter used for said frequency axis interpolation based on said signal corresponding to said maximum delay time.