MODULATION APPARATUS, MODULATION METHOD, DEMODULATION APPARATUS, AND DEMODULATION METHOD

摘要

PROBLEM TO BE SOLVED: To transmit information with audible sound waves based on a level that is not uncomfortable for human hearing sense and to improve the bit rate of transmission information.

SOLUTION: A modulation apparatus comprises a modulation section 51 in which the carrier wave 42 of an audible sound band is modulated by an encoded transmission signal 3 to generate a modulated signal; a masker sound generation section 44 for generating a masker signal to be output as a masker sound that prevents the modulated signal from being heard in transmission together with the modulated signal; and an acoustic signal generation section 52 for generating an acoustic signal by inserting the masker signal into the modulated signal.

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