Design And Implementation Of Data Transmission System In Short Distance Based On Audio Signal

Nowadays, with the popularization of mobile devices, data transmission within close range is increasingly desired by people. There are several types of short distance data transmission modes we are using, such as Bluetooth, NFC (Near Field Communication) etc. While Bluetooth has complicated operation steps, and NFC needs extra hardware support, so they can’t be widely used. The existing data transmission modes are not convenient, especially for improvisational small data transmission.In this thesis, I introduced another new way of data transmission based on audio signal, which could transfer data very conveniently in short distance with little hardware requirement, just loudspeaker and microphone. The technical principle of the method is a little similar with DTMF (Dual Tone Multi Frequency). While the frequency range that DTMF adopted overlaps the frequency of human voice, resulting in weak anti-interference function, besides, the data which each audio signal carries is relatively low. So how to effectively improve the recognition rate and transmission rate are the keys of this technology. I made a demand analysis based on data transmission by audio signal in short distance, introducing the design objective and functional needs of this system, based on which, I projected the layout and the working process of the system. After that I designed the system in a detail way and finally realized it. The system covers three parts:Basic Framework, Transmitting Part and Receiving Part. The Basic Framework provides service and foundation for the system, such as RS Codec, frequency mapping, configuration information. The Transmission Part is responsible for sending data, including data coding, audio synthesis, audio transmission. The Receiving Part is in charge of receiving data, including audio acquisition, audio recognition, data decode. I tested and verified the prototypical Demo and released application. I also analyzed and demonstrated the practical application effect of the Transmitting Side and Receiving Side.I designed and implemented the system. It is easy to operate and convenient on impromptu transmission in short distance. Such system can be used in many fields and scenarios as a sub module, such as business card exchange, e-payment, broadcasting etc. It will bring more convenience and happiness for those who use it.