Design And Implementation Of IRIG-B Code Baseband Circuit Based On FPGA

The main purpose of this paper is to design IRIG-B code circuit for the received timeinformation, then implement the direct sequence spread spectrum and the DBPSK signalmodulation based on digital signal processing. Coding circuit is mainly constituted bythe time receiving unit, processing unit and IRIG-B encoder. And the transmitting circuit ismainly composed of baseband processing unit and the band processing unit. All modulesof the whole project are completed with Verilog HDL language, and then connectall modules of the system, and finally got functional simulation through theSignalTap tool. All the work is completed on Altera, Cyclone III E series FPGA (fieldprogrammable gate array) chip. Firstly the paper proposes an IRIG-B Code basebandcircuit applied to time receiving, processing and sending based on FPGA. And thendiscusses the theoretical basis of each module circuit as well as the detailed realizationmethod. The coding part mainly includes GPS module, time pre-processing moduleand IRIG-B encoder, and the sending part includes differential encoder, direct sequencespread spectrum module and BPSK module. All the modules are given the simulationwaveforms, and finally compiled and downloaded to the Altera’s DE0developmentboard for simulation.The simulation results show that the system works correctly, stableperformance, occupies relatively less resource, fully meet the design requirements.