MODULATION DEVICE, DEMODULATION DEVICE, SOUND TRANSMISSION SYSTEM AND DEMODULATION METHOD

A problem is to increase possibility of extracting data from sound in a system which transmits data using the sound as a transmission medium. Frames are transmitted while shifting the transmission timing among a plurality of frequency bands, whereby tolerance for multipath fading, noise mixing, or the like is obtained and improvement of a substantial transmission rate can be expected compared to a case where one frame is transmitted using only one frequency band. When selecting blocks forming a frame, since a block is selected under a condition that a time period necessary for collecting sound, on which the blocks to be selected are superimposed, becomes shorter, even if a phenomenon, in which a substantial rate of data transmission decreases, occurs, it becomes possible to suppress a decrease in rate.