Research On Notch Bandwidth Compression Method In Radiation Interference Cancellation System

The adaptive interference cancellation system for radiated interference will attenuate the adjacent frequency useful signal.For the radiated interference between the antennas of independent stations,a notch bandwidth compression method is used in the interference cancellation system to not only cancel the interference signal but also avoid the useful signal.Attenuation,and under the condition of limited frequency resources,can also achieve the purpose of reducing the frequency interval of the transceiver platform to ease the tension of frequency resources.Firstly,this article introduces the theoretical basis of adaptive interference cancellation technology,discusses the principle,composition and main application of adaptive filter.It analyzes and compares the two main adaptive filtering algorithms,and divides interference cancellation technology into active and There are two passive methods,the specific cancellation methods of the two methods are explained,and the principle of the active interference cancellation technology using orthogonal vector synthesis is further analyzed.Secondly,for the two-channel interference cancellation system,the amplitudefrequency characteristics of the interference cancellation system are given from the frequency domain perspective,which illustrates the mechanism of adaptive signal cancellation caused by useful signal attenuation and the existence of notch bandwidth;from the time domain perspective,it illustrates the usefulness The signal after the signal and the reference signal pass through the multiplier will leak to the weight value,and finally the composite signal has a useful signal frequency component,resulting in attenuation of the useful signal.A notch bandwidth compression method is given for single-frequency interference and multi-frequency narrow-band interference in a twochannel system.MATLAB/Simulink is used to build a simulation model of the system to simulate the interference signal and useful signal before and after the notch bandwidth compression method is used.Analysis and comparison to verify the effectiveness and feasibility of this method.Finally,in order to solve the problem of notch bandwidth compression of the colocated broadband interference cancellation system,a three-channel three-channel interference cancellation system with three delay taps is given,and a three-channel threechannel interference cancellation system model with three delay taps is established.The weight differential equation is used to find the relationship between the cancellation ratio and the interference signal bandwidth,gain,and tap delay time.The cancellation characteristics of the three-channel adaptive interference cancellation system are analyzed,and the interference of the three-channel system under the bandwidth of MHz is proved.The offset effect is better than the two channels.A notch bandwidth compression method suitable for a three-channel interference cancellation system is proposed.The comparison and verification of the notch bandwidth compression method under three-channel system under the condition of broadband interference signal before and after simulation results show that the addition of notch bandwidth compression method in the interference cancellation system can prevent the useful signal from being cancelled,and basically does not affect the cancellation effect of the interference signal.