Signal Enhancement And Anti-jamming In X-band Active Listening Study

This thesis realized the distance with the door and carrier cancellation technology X band active interception, uses the array antenna system realize adaptive beam forming, restrain the range gate of interference, and from the device to improve and wavelet denoising two aspects of X band active interception system for noise reduction processing.Briefly analyses the carrier cancellation theory, introduces the matching double T is the core of the broadband carrier cancellation technology will be the original single frequency signal system expanded to broadband signal system. Introducing range door technology, through the system beat signal model validation distance door effect, improve the original analog range door, realized the multiple filter consists of digital range door, and through the simulation results verify the system to add range door anti-interference ability was improved.Range door for most of the frequency beyond range door frequency threshold interference can have very good inhibition effect, but for frequency in frequency in the threshold and power greater interference signal does not play a significant role. The single channel access system to multi-channel receiving array antenna system, realized the adaptive beam forming system, so as to this part of the noise suppression. According to the self-designed array antenna with X band active interception system simulation, the simulation results show that the system meets the project requirements.Through the system device and appropriate target vibration body choice can be X band active interception system detection signal signal-to-noise ratio improve, but could not complete the system noise elimination. According to the echo signal has a mutation and non-stationary characteristics, this paper, from the point of view of signal processing based on the study of wavelet de-noising signal processing method for X band active interception system for signal denoising research.