Implimentation Of Low Speed Acquisition Circuit Of Wideband Signal Based On High Speed Switch

Sampling is a bridge between the physical world and the virtual world,the cornerstone of modern information systems.With the development of modern information technology,the information system is gradually evolving to the broadband.The classical Nyquist sampling theory requires that the information system must acquire and process signals at a rate that is twice the bandwidth of the signal,resulting in an increase in the analog-to-digital conversion rate of the information system.In the practical application,in order to effectively store and transmit information,many information systems need to compress the front-end data.The treatment method of high-speed sampling and compression have brought great redundancy to the traditional information system.In 2006,E.J.Candes,J.Romberg,T.Tao and other famous scholars put forward for sparse or compressible signal,under the premise of ensuring no loss of the amount of information,it can be sampled and reconstructed in less than twice of the signal bandwidth.For more than ten years,compression perception and its related theoretical basis have been widely used in image processing,signal processing,geophysics,medical imaging,computer science,applied mathematics and other fields.This paper mainly explores the analog signal Nyquist frequency sampling method based on compressed sensing.The compressed sensing theory is born in the discrete time domain,and the design of the observation matrix in the continuous time domain has always been the focus of the research based on compressed sensing signal acquisition.,Based on the well-known random demodulation compressed sensing framework,according to the time and frequency characteristics of high speed switch,this paper designs a Nyquist frequency sampling system based on high speed switch.First of all,this paper compares and analyzes the basic principles of the classical sampling theory,non-ideal sampling and compressed sensing,and discusses the limitations of compressed sensing in analog signal sampling.Secondly,the classical compressed sensing sampling method and random demodulation sampling architecture are analyzed,and the lowest rate of random demodulation is determined by theoretical and experimental analysis.Based on this,this paper analyzes and summaries the time-frequency characteristics,the relevant performance indexes and the different modes of the high-speed switch circuit.It also determines the design constraints of the parameters of the mixing module based on the high-speed switch and provides an effective solution to the design of the random demodulation module based on the high-speed switch.Finally,this paper uses the design of the mixer circuit design with ADI's ADG1211 four-channel single-hand single-throw switch,and designs the filter circuit with the cut-off frequency of 1MHz.By using the XADC module of Znyq of Xilinx company,the effective acquisition of 100Mhz wideband signal with compression ratio of 100:1 is completed on the Zedboard platform.