The Research And Implementation Of High Dynamic Spread Spectrum Signal Simulation

Spread spectrum communication receives widespread attention and has been rapidly developed due to its excellent anti-interference ability.In the spread spectrum communication system,signal simulators which can provide the convenient test conditions for the receivers' development process are the key facilities for the development of receivers.At the high dynamic scenario,it is the key technology for simulators to generate the high dynamic signal with high-order characteristic states precisely.Therefore,this paper mainly studies the technologies for the spread spectrum signal simulation.An any-order DDS model with error control is proposed,an approach to simulate high dynamic DS-FH signal based on third-order DDS is provided and the implementation for the high dynamic DS-FH signal simulation based on FPGA is illustrated.The main research results of the paper are as follows:1.The principal of spread spectrum communication is briefly introduced,and the mathematical models of DS-SS?FH-SS and DS-FH are researched.2.For the high dynamic signal simulation technologies,the high dynamic DS-FH signal received by receivers is taken as the research object,and the signal mathematical model related to the motion state is established.According to the mathematical model,a physical meaning of the Doppler simulation method?Doppler simulation method based on third-order DDS?an any-order DDS for Doppler simulation are researched and verified by simulation.On the basis,an error correction method is introduced for the any-order DDS model to amend the phase error resulting from the quantization error of each parameters.3.The method for the high dynamic DS-FH signal simulation is studied and an approach based on DDS to synthesize IF phase with hopping frequency is given,that the approach can reduce the difficulty and complexity of system engineering compared with the direct frequency synthesizer or indirect frequency synthesizer.When the phase error correction is introduced in the simulation,the experimental results indicate that the method to simulate high dynamic DS-FH signal is effective.4.Finally,based on the theorectical study,an implementation architecture to simulate high dynamic DS-FH signal based on FPGA is provided.Also,the specific function,port definition and logic process diagram for the key modules are described in detail.