Design Of Zero-IF Weather Facsimile Receiver Based On PCIE Bus

Meteorology fax broadcasting covers almost all sea areas of the world.The ship can obtain useful information such as sea weather forecasts and trends without delay issued by the coastal stations nearby via meteorology fax receivers. Most receivers now use the structure of double-stage superheterodyne,which is complex in processing analog signals and low in intergation level. Thus results in malfunction and sail dangers.For solve the problems in receivers now, the paper presents a design of PCI-E based zero-IF receiver from the angle of changing structure of receivers. RF signal processing does not require IF bands, replaced by the method of zero-IF sampling. Receivers consist of RF signal processing module,digital signal processing module and PC control module.The first module consists of antenna impedance matching and signal protection circuits, passive bandpass filter, LNA and AGC; digital signal processing module achieve the mission of Zero-IF sampling, and do digital filtering, quadrature mixing, digtal demodulation processing and storage and dual-port RAM data buffer in FPGA. The communication between PCI-E bus and PC is accomplished by bridging chip PEX8311. The PC control module have the task of choosing receive modes, showing the receive states, exchanging orders, displaying image data and recording files. The flexibility in designing digital filters improves the result Design improves efficiency of data transmission, and is also convenient for image processing via PCIE bus.The paper analyzed the structure and parameters of receivers. Compare with superheterodyne weather fax receivers, we qualitatively analyse the performance of zero-IF receiver, and also complete analysis and design of each module. Finally we analyze the results and prove the system design is reasonable.