| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultrasonic communication system that takes into consideration difference in frequency characteristics that microphones of individual mobile terminals have, the ultrasonic communication system being not influenced by a Doppler effect due to noise and the movement of the mobile terminals, and exercising an excellent communication performance with a simple configuration.SOLUTION: A beacon 5 that oscillates an ultrasonic wave in a salesroom is installed, and an ultrasonic communication system 1 communicates with a mobile terminal 6 of a customer. After converting two digital signals into an analog signal as a combination of a first carrier and a second carrier that have adjacent frequencies and include specific identification information of a store and as transmission information about which the active areas of the first carrier and the second carrier alternate on the time axis, the analog signal is transmitted in the salesroom from the beacon. The transmission information is received by a portable microphone of the mobile terminal of the customer in the salesroom, and a demodulation processing unit demodulates the transmission information including the specific identification information for presence confirmation of the customer by comparison calculation of a pattern corresponding to the sound volume levels on the time axis of the first carrier and the second carrier. |
