NON-CONTACT AUTOMATIC FARE COLLECTION SYSTEM

摘要

An electronic transit fare card for use in an automatic fare collection system that is activated to pay the fare when brought into proximity with a coil mounted on access equipment at the entrance and exits of a transit system. The electronic fare card makes a non-contact communication connection with a target assembly by momentary coupling to a RF magnetic field carrier signal that is modulated either by a source impedance modulator on the card or by a target modulator. Both card and target assembly are shielded against electrostatic discharge (ESD) and unwanted radio transmittion (EMI) by means of magnetically permeable electrostatic shields, thereby preventing the generation of unwanted radio transmissions and the accidental modifications of fare card data by ESD or stray radio signals. While our invention uses a coupled source impedance for modulation of a carrier signal, other modulation schemes may be used as known to those experienced in the art.