Design And Experimental Of Digital Radio Frequency Memory System

With the development of Digtial Radio Frequency Memory(DRFM),it has been widely used in Radio Frequency Simulation System(RFSS),Electronic Countermeasure(ECM)and other fields.In RFSS,the simulation of target echo has the characteristics of good coherence and accurate speed in DRFM system,it can provide a comprehensive test platform for the performance testing,technical verification and evaluation of radar.In ECM,the deceptive jamming signal produced by DRFM has the characteristics of the phase relation determination,the small frequency error and the wide range of time delay,it can implement more effective deception jamming to radar.However,with the emergence of the new system radar,especially the wideband radar system,it is imperative to develop a wideband and low-spurious DRFM system.In this thesis,through depth analysis of current technology and the working principle of DRFM system,the spurious model of the system is established by Matlab,and the simulation analysis is carried out.The influence of quantization error,inter channel mismatch,sampling clock harmonic spurious,sampling clock jitter and sinc fading on the spurious performance of the system is mainly studied,and several ways to improve the spurious performance of the system are put forward.Secondly,combined with the development project of coherent radar target simulator,the design and implementation of the wideband low spurious DRFM system are carried out,and the implementation structure of the wideband low spurious DRFM system is given.According to the top-down design method,the implementation methods of all the key units are given.The design and implementation of the hardware,software and high-speed circuits of each key unit are completed.At the same time,the experimental testing method of the key performance of the system is given and the experimental results show that when the sampling rate is 2.5GHz,the instantaneous bandwidth of 1GHz can be achieved,and the spurious performance is better than-50 dBc.Finally,based on the actual demand of the RFSS,a wideband radar echo generator algorithm is designed.This thesis mainly introduces the implementation of the key algorithms such as digital orthogonal frequency conversion,digital FIR filter,wideband target characteristic modulation,wideband target doppler modulation and other key algorithms,and the experimental menthod is also introduced.Test result shows that this system can meet the requirements of current wideband RFSS.