Research On Reconstruction Algorithm Of Under Nyquist Sampling And Signal

Human beings have entered a digital times,many signal processing has entered the digital field from the analog field.Sampling theory is the gateway to the digital world,and it is the key to realize the transformation,which covers all the relevant aspects of the conversion of continuous time signal to discrete signals.The famous Shannon theorem has become a milestone in the history of the digital age,based on compressed sensing theory of sub Nyquist sampling will great reduce sampling rate,the drive ultra wideband communication and radar imaging and other areas of rapid development.Scientists have also studied a variety of signal reconstruction algorithm,mainly based on compressed sensing of the greedy algorithm,etc..The orthogonal matching pursuit algorithm can recover the spectrum of the target signal very well in the case of sparse degree.However,many of the signals in the real environment are unknown,including sparse signals,and then propose a full blind multi band sparse signal reconstruction algorithm based on the modulated wideband converter.This paper is mainly for modulated wideband converter sub Nyquist sampling method of the sparse signal with multi frequency sampling to use low speed ADC sampling of high speed target signal,and then the reconstruction of the target signal.In the real world signals are analog,when we on signal processing applications are digital,so we usually must be sampled digital signal to analog signal and Shannon theorem requires that the signal sampling frequency must be high and equal to the highest frequency of 2 times.Sampling of broadband signals has become the bottleneck of the development of a lot of fields,and then there is the Nyquist sampling technology.This paper is mainly based on the sampling of the sparse signals with unknown multi band signals,and then the target signals are reconstructed.First of all,mainly introduces the compressed sensing theory knowledge,including the role of signal sparse representation,the observation matrix and the reconstruction algorithm,the vigorous development of sub Nyquist sampling technique to the milestone,most less sampling techniques are based on compressed sensing theory.Second,we first introduce the existing under sampling technology,mainly including time alternating sampling,filter group sampling,frequency domain sampling and bandpass sampling.Then,the sampling technique,which is used in the paper,is mainly analyzed,which is to realize the sampling of multi band sparse signals.Third,a full blind reconstruction algorithm based on the modulated wideband converter is proposed,that is,sparse adaptive matching pursuit algorithm,and then compared with the orthogonal matching pursuit algorithm and simulation analysis.Finally,it is the summary of this paper and the future of the Nyquist sampling technology.