The basic workflow: the reader transmits a radio frequency signal predetermined frequency through the transmitting antenna, induced current, RF card when the RF card entry transmitter antennas work area for energy is activated; RF card itself encoded information transmitted via the card built-in transmission antenna out; reception antenna system to the radio frequency carrier signal transmitted from the card, is transmitted to the reader via the antenna controller, the reader received signal is demodulated and decoded and then back to the host system performs the correlation process; the main system logic determining the legitimacy of the card operation, and make the appropriate treatment for the control of different settings, issues a command signal for controlling the operation of the actuator.
In the coupling - Aspect (electromagnetic inductor), a communication process (FDX, HDX, SEQ), data transmission method from a radio frequency to the card reader (load modulation, backscatter, higher harmonic) frequency range, and the like, different the method of non-contact transmission are fundamentally different, but all of the readers on the functional principle, and very similar design configuration which determines all the reader high frequency can be reduced to two basic control unit and an interface module. Frequency interface includes a transmitter and a receiver, the function comprising: generating a high frequency RF transmit power to activate the card and provide energy; modulated transmission signal, for transmitting data to the RF card; receives and demodulates the RF card from a high frequency signal. Interface design different frequency radio frequency identification system has some differences.
Reader function control unit comprises: a communication with the application software, application software and execute the commands sent; RF card communication procedure control (master - slave principle); codec signal. There are some special system for the implementation of anti-collision algorithm, the data between the RF card and reader to be transferred to encrypt and decrypt, as well as additional features such as authentication between the RF card and reader.
Read from the RFID system is a critical parameter. At present, the price of long-distance radio frequency identification system is also very expensive, so look for ways to improve their reading and writing distance is very important. Factors Affecting reading distance RF card comprises an antenna coupled to the operating frequency, Q value of the receiving sensitivity of the RF output power of the reader the reader, the power consumption of the RF card, and an antenna resonance circuit, antenna, and a RF card reader degree, and an RF energy and the energy of the card itself and the like to obtain transmission information. Reading from and writing are different from most systems, and writes the read distance is approximately 40% to 80% of a distance.