Tham khảo tài liệu 'development and implementation of rfid technology part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 11 A Low Cost Anticollision Reader Dan Tudor Vuza1 Reinhold Frosch2 Helmut Koeberl2 and Damien Boissat2 institute of Mathematics of the Romanian Academy 2Frosch Electronics OEG Graz 1Romania 2Austria 1. Introduction The chapter presents some aspects related to the design of a low cost anticollision reader based on the HTRC110 reader chip from NXP Semiconductors NXP Semiconductors 2006 a and the AT91SAM7S64 controller from Atmel. The HTRC110 reader chip was mainly intended for integration into systems that need to identify one single RFID tag at a time. At the request of the host the chip sends the adequate command to the tag retrieves the answer of the latter in analog form digitizes the data and offers to the host the data retrieved from the tag in binary format. The chip does not provide support for collision detection and anticollision identification procedures in case that several tags in the antenna field respond to the same command at the same time. Nevertheless the chip does provide access to the analog demodulated signal representing the response sent by the tags via load modulation of the carrier. This access was meant by the producer for the purposes of antenna tuning and testing. In the present design it is by exploiting this feature that one achieves the anticollision functions. In section 2 of the chapter one describes the general configuration of the reader at block level and particularly how the internal ADC of the AT91SAM7S64 controller is used for converting the test signal of the HTRC110 chip to numeric format and what signalprocessing procedures are used for extracting the bit information from the signal and detecting collisions on bit positions. Included is also a brief description of the communication facilities of the reader with a host PC such as RS232 USB and wireless. In section 3 one addresses some aspects of the concern whether the analog signal provided by the HTRC110 chip is adequate enough for collision detection. The main point here .
