| 摘要 |
PROBLEM TO BE SOLVED: To provide an embedding device of different acoustic signals to acoustic signals, capable of preventing duplication in a normal state by reproducing sound based on inaudibly embedded different acoustic signals when sound being played is sampled and duplicated and then the acoustic signals after the duplication are to be reproduced.SOLUTION: A first acoustic frame of N samples is read from first acoustic signals and a second acoustic frame of N samples is read from second acoustic signals (S1, 2). Frequency conversion is performed to the first acoustic frame and the second acoustic frame to obtain a first spectrum and a second spectrum (S3, 4), and in signal components of the second spectrum, the signal components whose frequencies are Fk and higher are removed, and the signal components whose frequencies are Fk and lower centering on a frequency Ft larger than the frequency Fk are folded in a frequency direction of a high frequency (S5). The folded signal components of the second spectrum in the range from a frequency Ft+(Ft-Fk) to a frequency 2*Ft are combined with the signal components of a corresponding frequency of the first spectrum while being attenuated (S6). |
