| 摘要 |
<p>A device 3 for transmitting data by means of an audible sound wave is disclosed. The device generates or receives data to be transmitted. The device also measures the ambient noise level. The device produces a sound wave that is modulated by the data and adjusted to be unobtrusive with respect to the ambient noise level. The device then transmits the sound wave. The sound wave is received by a corresponding receiver, which extracts the data. Because the data is transmitted as an audible sound wave, it is transmitted only for a limited range (for example, it is confined within the boundaries of a room). This may enhance security and be advantageous in certain applications, for example those where it is desired to ensure that a recipient is within a particular predefined area.
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