Abstract: According to the principle of a modern deceptive jammer,which can generate a simultaneous RGPO and VGPO jamming signal based on DRFM and DDS architectures,the frequency spectrum of the jamming signal generated by one such jammer is derived.Then,by a comparison between this frequency spectrum and another spectrum of a jamming signal generated under an ideal condition,it can be found that the highest peak of the true jamming signal spectrum has an additional offset,and the amplitude of it is attenuated a little.This feature of the jamming signal in the frequency domain is helpful for radar to identify the occurrence of the jamming.The simulation results verify the analyses.