The Research And Design Of 125kHz Radio Frequency Identification System

Radio Frequency Identification (RFID) is a manner of un-touch data communication by radio in mutual directions. At the same time, RFID can identify the aim and collect information rapidly. RFID has some outstanding virtues such as use conveniently, data communication speedy, safety highly. These virtues make the study of technique in RFID important. The technique of RFID is used widely in many occupations. For example, traffic and transport, goods assignment, military and national defense. In the future, the technique of RFID has enormous potentiality and chance in the open global market. This paper studies the RFID system in 125 kHz, and designs a set of separately reader circuit, it can identify tag and communication data range from 2cm to 10cm.RFID technology is embedded with many modern techniques, it is an interdisciplinary field. This paper describes the development trends in RFID firstly. By the study of basis theory in RFID, it researches thoroughly the channel coding and modulation, anti-collision mechanism, data safe, the control of microprocessor. In the design of hardware, the paper details in introducing the reader circuit and function module, especially the theory and method of design in D-type power amplifier, Manchester code and coil. At the same time, it elaborates the function and character of MCRF250 tag. Moreover, the paper states the design of software in RFID system, introduce the control process of microprocessor and interface in PC.