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The Architecture of Electronic Data Carriers Before we describe the functionality of the data carriers used in RFID systems we must first differentiate between two fundamental operating principles: there are electronic data carriers based upon integrated circuits (microchips) and data carriers that exploit physical effects for data storage. Both 1-bit transponders and surface wave components belong to the latter category. | RFID Handbook Fundamentals and Applications in Contactless Smart Cards and Identification Second Edition Klaus Finkenzeller 10 Copyright 2003 John Wiley Sons Ltd. ISBN 0-470-84402-7 The Architecture of Electronic Data Carriers Before we describe the functionality of the data carriers used in RFID systems we must first differentiate between two fundamental operating principles there are electronic data carriers based upon integrated circuits microchips and data carriers that exploit physical effects for data storage. Both 1-bit transponders and surface wave components belong to the latter category. Electronic data carriers are further subdivided into data carriers with a pure memory function and those that incorporate a programmable microprocessor Figure 10.1 . This chapter deals exclusively with the functionality of electronic data carriers. The simple functionality of physical data carriers has already been described in Chapter 3. 10.1 Transponder with Memory Function Transponders with a memory function range from the simple read-only transponder to the high end transponder with intelligent cryptological functions Figure 10.2 . Transponders with a memory function contain RAM ROM EEPROM or FRAM and an HF interface to provide the power supply and permit communication with the reader. The main distinguishing characteristic of this family of transponders is the realisation of address and security logic on the chip using a state machine. 10.1.1 HF interface The HF interface forms the interface between the analogue high frequency transmission channel from the reader to the transponder and the digital circuitry of the transponder. The HF interface therefore performs the functions of a classical modem modulator-demodulator used for analogue data transmission via telephone lines. The modulated HF signal from the reader is reconstructed in the HF interface by demodulation to create a digital serial data stream for reprocessing in the address and security logic. A .