| 摘要 |
A composite signal having frequencies within a sonic first frequency bandwidth may be received from a communication media on a receiver. The composite signal may include an audio base signal and at least one code signal. The code signal may be encoded with a code, may have a duration shorter than a duration of the base signal, and may have a second frequency bandwidth within the first frequency bandwidth. The composite signal may be output on a speaker, the speaker converting the composite signal into sound. While outputting the composite signal, a signal processing device may detect the output sound corresponding to the code signal. The code may be determined from the detected output sound corresponding to the code signal. Data associated with the code may be retrieved from a data storage device. The retrieved data may be displayed on a display device. |
