Patent ID: 7835475

Claim:
A digital broadcast receiver for receiving digital broadcasts using OFDM, comprising: a Fourier transformation circuit to perform Fourier transformation of a received signal to obtain a plurality of carrier signals including a plurality of DBPSK carrier signals respectively carrying a DBPSK signal; a phase difference calculation unit to detect a phase difference between adjacent symbols in each of the plurality of carrier signals; a correlation calculation unit to calculate a correlation value representing the correlation between the phase difference detected by the phase difference calculation unit and zero or π; and a determination unit to determine whether an OFDM signal is present, wherein the plurality of DBPSK carrier signals are allocated in a predetermined allocation pattern, the phase difference calculation unit sequentially detects the phase differences for a plurality of carrier signals in the allocation pattern while sweeping frequency, the correlation calculation unit respectively calculates sums of the correlation values for the plurality of carrier signals in the allocation pattern in the sweeping, and detects a maximum sum of the correlation values, the determination unit determines that the OFDM signal is present if the maximum sum of the correlation values is larger than a predetermined threshold.