TERMINAL DEVICE, INFORMATION ACQUISITION SYSTEM, INFORMATION ACQUISITION METHOD, AND PROGRAM

PROBLEM TO BE SOLVED: To acquire, using one microphone, a plurality of sound waves having information superposed thereon and being the same in frequency, and extract information superposed on a sound wave transmitted from a transmitter near a terminal device among a plurality of transmitters each disposed at a different location.SOLUTION: A terminal device 10 demodulates sound waves transmitted by transmitters 30A, 30B and being the same in frequency and extracts a signal at a level corresponding to the amplitude of the sound wave. The terminal device 10 binarizes the extracted signal with a prepossessed threshold and specifies a transmitter identifier represented by the sound wave. If the terminal device 10 is near the transmitter 30A, the signal obtained from the sound wave of the transmitter 30A is greater than or equal to the threshold and the signal obtained from the sound wave of the transmitter 30B is less than the threshold, so that the transmitter identifier of the transmitter 30A is obtained. If the terminal device 10 is near the transmitter 30B, the signal obtained from the sound wave of the transmitter 30B is greater than or equal to the threshold and the signal obtained from the sound wave of the transmitter 30A is less than the threshold, so that the transmitter identifier of the transmitter 30B is obtained. 【課題】情報が重畳され周波数が同じである複数の音波を一つのマイクロフォンで取得し、各々異なる位置に配置された複数の発信機のうち端末装置に近い発信機から送信された音波に重畳されている情報を抽出する。【解決手段】端末装置１０は、発信機３０Ａ，３０Ｂが送信する同一周波数の音波を復調し、音波の振幅に応じたレベルの信号を抽出する。端末装置１０は、抽出した信号を、予め有する閾値で二値化して音波が表す発信機識別子を特定する。端末装置１０が発信機３０Ａに近い場合、発信機３０Ａの音波から得た信号が閾値以上となり、発信機３０Ｂの音波から得た信号が閾値未満となるため、発信機３０Ａの発信機識別子を得られる。端末装置１０が発信機３０Ｂに近い場合、発信機３０Ｂの音波から得た信号が閾値以上となり、発信機３０Ａの音波から得た信号が閾値未満となるため、発信機３０Ｂの発信機識別子を得られる。【選択図】図１