Based On Active Rfid, Electronic Road Signs

This dissertation focuses on an active RFID application in intelligent transportation—the electronic signpost system.The main function of the system is that, the ground equips which is established in road corner, wireless sends the direction and other needed imformations which is digital encoded to the car equips. Meanwhile, the car equips must be able to decode, so it can translate the information into nature voices, and achieve human-machine communication.This paper will first analyze the function, requirements and the using environmental features of the electronic signpost system, thus design the base framework. Then according to the actual use requirements, the paper chose a suitable audio encode mode (MP3), determined the chip for function modules, arrangemented for the corresponding hardware interfaces, and finally finish the design of application software.The key problem has been solved of this paper as following:1. Used high-performance ISM-band transceiver to constitute transceiver module, meet the requirements of Large amounts of data's long-distance, high-speed, high reliability RF transmission, ensure the vehicles which traveling on the relevant road sections can receive effective and corect information.2. Used high compression ratio and high quality MP3 encoding audio data, and restored the voices through the decoder chip.3. Used single-wire application of standard SPI interface to connect RF-chip, and used general IO port to connect flash and decoder chip, to some degree, these connections meet the system's high speed demands.4. Analyzed the practical application demands of the system, increased a storage module in the receiving device, so before new data has received, the device could repeat last information.