| Traditionally, NFC technology has been widely used in mass transit,such as public transit card, access control, etc., because of its faster response speed, higher security, lower production cost and so on.And in recent years, mobile phone as the representative of the very rapid development of mobile terminals. The huge demand for mobile payments,making NFC technology has been embedded into mobile phones and other terminals in the form of NFC tag, the rapid integration of NFC technology and the mobile Internet, NFC payment technology in the field of global development very rapidly, so that the NFC technology has a very big development.However, due to different manufacturers, uneven production technology, different technical standards, inconsistent usage scenarios and other reasons, the form of NFC tag in circulation on the market now is different, with different parameters, and can not be unified. Therefore, it is very necessary to test the NFC tag's various aspects of performance with a high compatibility test instrument before the introduction of the product.Now, test instruments related mainly monopolized by a few large production development and in China is still blank.The high price of the NFC test instrument for the majority of the manufacturers discouraged.Therefore, in order to quickly seize the market, their products have been put into the market without well tested, for a wide range of promotion and use. These reasons lead to the existing NFC tags will be very different, the use of the process may have a greater performance bias, often there are some integrated NFC-enabled mobile terminal can not be used normally,or only support part of the scene, etc. This problems deepened difficult to promote NFC technology.Aiming at the serious problems, this project proposed the design of an adaptive NFC test instrument based on FPGA technology. This paper mainly focuses on two aspects of the NFC communication system: First,achieving NFC communication system modulation and demodulation based on FPGA technology; Second, achieving the test instrument to produce the interaction of the electromagnetic field to adjust the physical parameters based on the upper PC Configuration instructions. The following achievements and innovations were achieved:1 .The influence factors of the parameters of the electromagnetic field of the test instrument are studied. Such as the factors affecting the magnetic field strength, carrier frequency and pulse rise time.2.About the modulation and demodulation system of NFC communication, a new demodulation method based on FPGA is implemented. Synchronous sampling method is used to replace the traditional mathematical operation. The demodulation system with high efficiency and high compatibility can be realized by taking into account the various demodulation types and the influence of various subcarrier waveforms.This project can fill the gaps in the domestic NFC test instrument.solving the problem that the industry is monopoly of foreign large companies. At the same time, because of the physical parameters of the electromagnetic field generated by the test instrument, such as the strength of electromagnetic field, electromagnetic field carrier frequency, rise time of Pause pulse can be configured according to the configuration instructions, this test instrument can test more kinds of NFC electronic tags,Which effectively solves the problem of poor compatibility and small matching range of the existing test instrument, and has better adaptability and compatibility. In addition, this test instrument uses the new demodulation method makes the whole system efficiency greatly improved. |
PDF Full Text Request