Design And Implementation Of Weather Facsimile Receiver Based On PCI-E Bus

With the continuous acceleration of economic globalization,ocean voyage has become an important form of politics,economy and cultural exchange in the world.As an important way to obtain the meteorological information of the sea area,the weather facsimile receiver has become one of the indispensable equipment to ensure the safe navigation of ships.At present,most of the commonly used weather facsimile receiver need to be equipped with a host board card.And in the process of image transmission to the host computer,it will occupy a lot of system resources,which shows that the system integration and the efficiency is low.Nowadays,the marine electronic equipment is developing towards the trend of digitalization and integration,so it is necessary to develop a new type of weather facsimile receiver combined with the development trend of today’s electronic equipment.In view of the strengths and weaknesses of the existing weather facsimile receiver,combined with the application environment of the third generation bus interface technology,the paper proposes a design scheme of weather facsimile receiver based on PCI-E bus.The fax system designed in the paper combines the fax board card with the host board card,which greatly improves the integration and digitization of the system.As a sub node equipment,the fax system is applied in the integrated navigation information system.The meteorological fax image is uploaded to the node host through the PCI-E bus,then processed by the node host and summarized to the integrated navigation information system host.The weather facsimile receiver system designed in this paper mainly includes three parts: RF front-end processing circuit,analog-to-digital conversion circuit,digital processing and system control circuit.Among them,the RF front-end processing circuit is mainly composed of frequency bands selection filter circuit,RF amplification circuit,local oscillator circuit,mixer circuit and automatic gain control circuit.The analog-to-digital conversion circuit is mainly composed of anti aliasing filter circuit,differential amplification circuit and A/D conversion circuit.The digital processing and system control circuit is based on AM5718 heterogeneous multi-core processor platform,and the peripheral circuit mainly includes NOR Flash circuit,SD card circuit,PCI-E bus interface circuit.The work flow of the system is as follows: the weather facsimile signal received by the antenna is firstly mixed twice by the RF front-end processing circuit to get the IF signal,then the analog IF signal is digitized,and the digital signal is sent to the DSP core of the main control chip for digital demodulation processing.At the same time,the ARM core,as the main controller of the system,is responsible for the overall control task of the fax system.Finally,the ARM core uploads the image file to the upper computer through the PCI-E bus.In this paper,the weather facsimile receiver system is designed in detail,and the performance index of this system is analyzed compared with other structures.On this basis,the design analysis and test of each functional modules of the system are completed.At the same time,the whole system is debugged and verified,which proves the correctness of the weather facsimile receiver system design.