FPGA-based Communication Data Acquisition System Design For ISO14443B

Non-contact IC card is a wireless communications technology based on the contactless IC technology. IC card can storage date,when IC card communicate with the inter-host, data can be read and rewritten. Since the non-contact IC cardis convenient, safe and reliable, it has been widely used in identity cards, debit cards, access control systems, transit charges. The non-contact IC Communication standard card mainly include ISO14443 B,which is proposed by Motorola, and ISO14443 A, which is proposed by Philips.ISO14443B protocol is a new kind of communication standard, the date is coded in NRZ, and the modulation of Transmission signalis ASK modulation, the modulation of Response signalis BPSK modulation. In this paper,i carried out specific researchon the standard protocol for ISO14443 B contactless IC card, specifically studied ISO14443 B protocol's theoryand IC card coding signal modulation. A company needs to collect real-time data and observe the date when the type of ISO14443 B IC card communicate with the host computer, in order to solve this problem, this paper creatively designed a wireless communication data Acquisition system which can collect in real-timecommunications Data.In this paper, in reference to the basis of the previous design of the classic BPSK modulation signal demodulation scheme based on the design of a new demodulation scheme BPSK modulated signal, which uses non-coherent demodulation of a BPSK modulation signal demodulating envelope signal, combined with FPGA chip, FPGA-based decoding scheme time measurement envelope signal BPSK modulation signal is decoded in order to obtain communication data BPSK modulated signals are transmitted, the program with previous classic demodulation scheme compared with the more obvious advantages, such as the difficulty of design and development costs greatly reduced, and the degree of stabilization circuit work better, less error-prone data demodulation.Data acquisitionsystems can be divided into two parts, which are analog circuit and digital circuit. analog circuits using operational amplifier circuit is designed to achieve the purpose of the circuit design to convert analog signals into digital signals, and it can be dividedintoseveral major parts, such as impedance match,AGC, several major part envelope extraction,filtering, level matching and so on..Digital circuit based on the the Xilinx FPGA chip, the model of the FPGA is spartan3xc3s400, the digital circuit is designedto decode the digital signal and then upload the data to a PC via UART bus. We can divide this part of the circuit into several major parts such as demodulation, AGC, data caching, serial data transmission and so on.Finally,the system is designed under the intergrated development ISE using Velilog language.Of the final,the test results show that: under certain conditions, the data acquisition system can acquisite the wireless communication signal between the external host and the non-contact IC card, and the datacan be collected in real-time, via analog circuit A / D conversion, FPGA signal that interact with data and instructions for collection, after data within the FPGA after processing is completed, the end of the first bit machine to upload, so engineers can collect data in real-time and observe the chip communication process. By observing the data, designers can find the errors of card communication data, then correct designpromptly, which will help speed up thedevelopment cycle of IC card design, reduce design costs, so the systemdesigned in this paper has a good application value and economic benefits.