| 摘要 |
Data is encoded as a number of audio tones forming a leader tone, a series of tones forming a start symbol and a greater number of data symbols following the start symbol which are each formed of a group of audio tones. The information is transmitted from a speaker or similar transducer to a microphone or similar transducer. The microphone is coupled to the input of a personal computer within which software is operative to analyze and decode the information. The leader tone is used to determine any frequency inaccuracies or errors which have occurred in the system. Based upon detected frequency inaccuracy or deviation, a frequency offset is employed within the system upon all received audio tones to adapt the system to the frequency inaccuracies or errors and produce correct data. |
