Patent ID: 8428756

Claim:
A data extraction device, comprising: a processor configured to: remove a low frequency component from an acoustic signal in which arbitrary transmission data is embedded, to generate a first low-frequency-removed acoustic signal; synchronize the first low-frequency-removed acoustic signal in accordance with a frame unit used when said transmission data was embedded in the acoustic signal by detecting synchronization points in the first low-frequency-removed acoustic signal; divide the first low-frequency-removed acoustic signal into frames on the basis of the synchronization points; and extract the transmission data from the synchronized first low-frequency-removed acoustic signal based on a correlation value obtained by multiplying each of the frames of the synchronized first low-frequency-removed acoustic signal by a predetermined spread code sequence, so as to identify a first bit value if the correlation value is plus at a synchronization point of the frame, and to identify a second bit value, if the correlation value is minus at a synchronization point of the frame, wherein the synchronizing includes calculating second correlation values between the first low-frequency-removed acoustic signal and the spread code sequence by iteratively shifting the first low-frequency-removed acoustic signal by several samples and detecting a point with a highest second correlation value as a synchronization point of the frame.