| This paper is focused on the design and the implementation of the GB/T 800/900MHz RFID conformance and performance test. Based on the PXIe modular virtual instrument and the Lab VIEW FPGA software platform, we have realized real-time communication and scheduling, conformance and performance test, man-machine interaction interface design.Firstly, under the evolution of RFID (Radio Frequency Identification) and Ⅵ (Virtual Instrument) technology, software-defined real-time test instrument of high performance has become a necessity. After investigation of the domestic and international research condition on the RFID tag test, we find that R&D and supply in the field of RF test are mainly distributed in the highly developed area. Thus, it is of importance to research and implement the RFID tag conformance and performance test on the platform of software-defined virtual instrument.Secondly, this paper gives a detailed introduction of the key techniques defined by the GB/T 800/900MHz air interface communication standard and the principle of the RFID system. We discuss the ASK modulation mode and give the time domain expression and power spectrum expression of 2-ASK signal based on a detailed mathematical derivation, andthis part acts as the foundation of the conformance test system design.Thirdly, the key algorithms of the test system are proposed, which are strictly consistent with the standard and can be compatible with Lab VIEW FPGA. The test system researched by this paper includes the simulated interrogator system which keeps accordant with the standard, and thus the performance of the key algorithm in the process of inter-communication has a direct influence on the correctness and stability of the whole test system. The problem is how to design robust algorithms applicable to real-time platform in noisy environment, however, this paper gives solutions to the energy detection, synchronization, decoding and error control problems, and has applied these algorithms into the real system, where the correctness of these solutions is testified.Finally, the GB/T 800/900MHz conformance and performance test system is implemented on the platform of the PXIe modular virtual instrument. Based on the design from the top down to the bottom, the top level structure of both the hardware and the software is analyzed firstly, and then the implementation of every layer of the system is described in detail. In the sequence of the physics layer, the MAC layer, the FPGA top layer, the drive layer and the application layer, the first two ones are built by the state machine nested in the single clock loop, and the third one is made up of multiple parallel structure under distinct clock domain, and the fourth one is consisted of different hardware configuration modules executed in parallel, and finally the last one is realized by the state machine nested in the condition loop. Obviously, their implementation differs from each other, however, this kind of distinction has no impact on the communication and data transfer between their interfaces. In fact, all parts act as a whole and work in coordination with each other via timing scheduling. In the meantime, the interaction design between the user and the test system is completed, containing the user interface and the data transfer.To put it in the nutshell, this paper designs a conformance and performance test system totally subjected to the GB/T 800/900MHz air interface protocol, and implements all the five software layers on the platform of the PXIe modular virtual instrument. The features are testified in the real test system, which include real-time interaction, parallelism, extendability and flexibility. |
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