Patent ID: 8653943
Filing Date: 2014-02-18
Classification: G06K

Abstract:
1. Radio frequency identification system provided for access control and comprising an interrogator (Interrog), including a data interface (DatInterf) for exchanging data with an interrogator logic circuit (PassCommProtImplLCI) for implementing the passive communication protocol, said logic circuit transmits a signal to a first input of an interrogator amplitude modulator (AMI), said amplitude modulator having a second input for receiving an output signal of a high-frequency signal generator (HFGen) and for transmitting an output signal as a signal to be transmitted, conducted through an antenna matching transformer (AMatchTransf) to a transmitting and receiving first interrogator antenna (AI and at least one transponder (Transp), including a transmitting and receiving first transponder antenna (AT said transponder logic circuit exchanges data with a memory device (Mem) and provides an output signal as a signal to be transmitted and conducted through a transponder amplitude modulator (AMT) to the transmitting and receiving first transponder antenna (AT said antenna (ATI) connected to a rectifier (Rect) provided to supply energy to transponder elements and connected to a clock extractor (ClExtr) provided to extract a clock signal for the transponder elements out of a magnetic field (BItransm) transmitted by the interrogator, and the protocol for passive communication between the interrogator (Interrog) and the transponders (Transp), providing, inter alia, the interrogator (Interrog) turns on its high-frequency signal generator (HFGen) so that the transmitting and receiving first interrogator antenna (AI a time interval (Δt) thereafter, the interrogator (Interrog) transmits an inventory request (InvReq) that the transponders (Transp within a specified timeslot thereafter, each transponder (Transp characterized in that the interrogator (Interrog) is provided with an interrogator logic circuit (ActCommProtImplLCI) for implementing the active communication protocol, said logic circuit exchanges data with the data interface (DatInterf) and transmits a signal to the interrogator amplitude modulator (AMI), whose output signal as a signal to be transmitted is conducted through the antenna matching transformer (AMatchTransf) to the transmitting and receiving first interrogator antenna (AI that the interrogator (Interrog) is provided with a receiving second interrogator antenna (AI said second interrogator antenna is connected through an interrogator active receiver (AMActRecI) for receiving amplitude-modulated signals to the interrogator logic circuit (Act-CommProtImplLCI) for implementing the active communication protocol, wherein the transmitting and receiving first antenna (AT said logic circuit exchanges data with a memory device (Mem) and whose output signal as a signal to be transmitted by the transmitter is conducted through a transponder active transmitter (AMActTransmT) for transmitting amplitude-modulated signals to a transmitting second transponder antenna (AT wherein each transponder (Transp) is provided with a high-frequency signal generator, and each transponder (Transp) is provided with a power supply circuit (SupplC), and wherein the logic for the active communication protocol determines that the interrogator (Interrog) turns on its active receiver (AMActRecI) for receiving amplitude-modulated signals only after the transponders (Transp thereafter, each transponder (Transp