The system of bus ID card is a contactless automatic identification technique. The hardcore is RFID, it is a radio frequency signal using automatic target recognition and access to relevant information technology.This technique is widely applied in many fields such as industry automation, commerce automation and transport control, especially in transportation control, freeway automatic toll collection parking lots control system, goods control, automatic pipeline production, safety control, storage control, animal management and vehicle’s theftproof system and so on.
The design is to achieve a simple circuit of bus ID card toll collector system .We setted up the toll collector system (reader)by general discrete device . Without contact of reader and responder(bus card)，we simple simulate this state to identify the bus card correctly then do the relevant movements, such as charging display and remind people by tweeting.The heart and basis is the part of power amplifier . In order to make the transponder passive working, the device applies with the mutual inductance between the two coils of the readers and transponders to achieve power transmission. Applying load modulation to transmit data from transponder to the reader in order that they can communicate with each other but not to rely on any other coupling manners.After reader do justice to the data,the information from transponder can be confromed ,then the reader will do the next operation.
Key words: Passive Radio Frequency Identification (RFID) Load Modulation Reader
