Research On Wideband Digital Receiver Technology Based On Compressed Sampling

Electronic reconnaissance is an indispensable part of information warfare.Using electronic reconnaissance can obtain enemy information in advance and provide support for friendly operations.Nowadays,broadband digital channelized receivers are the most used in electronic reconnaissance.With the increase of the complexity of the electromagnetic environment,receivers of this structure show more and more shortcomings.The increase of instantaneous bandwidth leads to more channelized branches.As a result,the sampling rate of the front-end ADC has increased,the sampling data has increased,and the entire system has become more and more complex.The channelized structure itself has cross-channel problems,and traditional receivers have gradually been unable to meet the requirements.Compressed sensing theory provides a new direction for the development of receivers.If the signal spectrum is sparse,high-speed signals can be sampled at a low sampling rate,breaking the Nyquist requirement for ADC sampling,and the radar signal just meets Compressed sensing requires signal,so the theory of compressed sensing can be applied to broadband digital receivers.In this paper,a wideband digital receiver with compressed sampling is researched.The structure of compressed sampling is a modulation bandwidth converter(MWC)structure.This structure can use a small number of branches to complete the signal sampling and reduce the complexity of the system hardware.The structure can mix all signals of all signal frequencies to the baseband,which improves the instantaneous bandwidth of the receiver.The MWC structure can only retain part of the frequency information during mixing.How to use this part of information to recover the original information is the research focus of this structure of the receiver.In addition,it is also necessary to consider how this structure is implemented in hardware.This article mainly focuses on the following researches on compressed sampling broadband digital receivers:First,the theory of compressed sensing is studied,and the feasibility of applying the theory of compressed sensing to broadband digital receivers is analyzed.Secondly,the principle of compressed sampling of the MWC structure is studied,and then the reconstruction process is deduced and analyzed.Finally,the feasibility of the whole process was verified through experiments.Research the measurement matrix of compressed sensing.The observation matrix of compressed sensing is introduced.The m-sequence is combined on the basis of the circulant matrix,and the circulant matrix based on the m-sequence is proposed.The m sequence is a pseudo-random sequence commonly used in communication.This sequence is easy to generate and the spectrum is evenly distributed.The circulant matrix can be obtained by simple shifting and cycling.Combining the two can obtain a measurement with many advantages.matrix.Through analysis,it can be seen that this matrix can meet the requirements of compressed sensing for the measurement matrix,and the correlation simulation with the Gaussian matrix is carried out.Finally,the comparison with other measurement matrices proves that the matrix also has good performance.The reconstruction algorithm of compressed sensing is studied.The problems existing in the OMP and Co Sa MP algorithms are improved,and the BOMP algorithm is proposed to improve the reconstruction probability.Simulation experiments show that the algorithm can improve the reconstruction probability.Aiming at the problem of unknown radar signal sparsity,DSAMP algorithm is proposed on the basis of BOMP algorithm.Simulation experiments show that this algorithm can accurately provide signal sparsity under good reconstruction probability,and it improves signal reconstruction under low signal-to-noise ratio.The signal-to-noise ratio of the signal.Finally,the performance of the compressed-sampling wideband digital receiver and the channelized receiver is compared,and the advantages and disadvantages of the two receivers are analyzed.