Design And Implementation Of Wireless Transceiver Based On AD936X

With the continuous development of wireless communication technology,people have put forward higher requirements for the timeliness of information transmission and the portability of communication devices.The existing wireless communication devices are sensitive to the transmission channel and the transmission distance is limited.Therefore,the wireless transceiver system with outstanding performance,low power consumption and small volume has become the focus of research at the present stage.Because of its high flexibility and openness,software radio technology makes up for the shortcomings of traditional communication in terms of integration,performance and repeatability.It provides a new way for the development of wireless communication technology.With the development of large scale integrated circuits,the design of Field Programmable Gate Array(FPGA)with RF transceiver provides a flexible and convenient solution for wireless communication systems.As a series of high-performance RF transceiver launched by ADI,AD936 X can not only achieve high speed transceiver of RF signals,but also greatly reduce the size of RF transceiver components.Therefore,the design of a wireless transceiver based on AD936 X plays a very important role in the wireless communication system with high integration,high performance,and software configurability.The content of this paper is the design and implementation of wireless transceiver based on AD936 X.Firstly,the paper studies the structure of wireless transceiver theoretically,and analyzes and deduces the design principle of the digital baseband in detail,including QPSK modulation and demodulation,direct sequence spread spectrum and de-spreading,and multi-antenna diversity reception.And the basic principles of carrier synchronization and PN code synchronization are further elaborated.Secondly,the baseband part of the transceiver is designed as a whole.In the data transmission module,the original data is processed by spread spectrum,which greatly improves the anti-interference ability in the transmission process.The paper also introduces the design method of generating pseudo random sequences,and analyzes the design method and application scope of the two PN code generators.In order to reduce inter-symbol interference and improve the signal-to-noise ratio of spread spectrum,it is necessary to design suitable shaping filter to filter high-frequency components and noise.At the receiver,with the analysis of the phase locked loop of carrier synchronization,for carrier synchronization,a zero-IF frequency and phase locked loop is adopted,which can well solve the contradiction between the convergence speed of the phase locked loop and the tracking precision of the locked loop.PN synchronization is based on the autocorrelation property of PN sequence,which realizes the acquisition and tracking process of PN code.After completing the design of the digital baseband part,the RF transceiver AD936 X is configured.The process is divided into three stages: first,design the configuration parameters of AD936 X and generate a configuration files;second,complete the interaction between FPGA and AD936 X through SPI;third,complete the information data transmission between FPGA and AD936 X through parallel data ports.Finally,the hardware platform is built and a transceiver with a transmitting antenna and four receiving antennas is set up.And then verify the correctness of the system and compare the transmission error rate between four antenna receiving and single antenna receiving.The comparison shows that the signal to noise ratio of the received signal gradually decreases with the increase of the power attenuation value of the transmitter,and the advantage of the receiver signal with the MRC is more obvious than the single antenna received signal in the bit error rate.In summary,the principle of wireless transceiver based on AD936 X is analyzed,and the project is designed and simulated on Vivado,then the hardware is debugged and the transmission performance is tested.The results show that the transceiver can achieve the desired requirements and achieve high-speed data transmission.This is of great significance for further research of wireless transceivers in the future.