Research On Frequency Spectrum Analysis Based On Digital IF

With the development of the technologies of micro-electronics,digital signalprocessing and computer, the technique of frequency spectrum analysis has hadprofound changes. To make it digital and be realized by softwares is a trend forspectrum analysis. Digital IF processing is the process that RF analog signal is changed into digitalsignal,then become to base band signal through DDC and digital filters.there havespecrum analysis on base band signal.This method of spectrum analysis is used rapidlyand efficiently. The whole structure of the spectrum analysis based on the digital IF is presented inthis paper,including four parts of ADC, multi-rate signal processing ,digital IFprocessing and frequency spectrum analysis .The part of ADC discusses the advantages anddisadvantages of several technologies of sampling such as Nyquist sampling,perpendicular sampling,band-pass sampling and Sigma Delta sampling.In the part ofmulti-rate signal processing,there intrduced decimation with integral factors and thesructure of multiphase filtering. The technologies of quadrature coherent detection of IFsampling and digital down conversion are presented in the three part of digital IFprocessing. The designs and simulations of CIC filters, HB filters, FIR filters of thestructure is also given. The algorithms of radix-2 FFT,the digital frequency conversionand multiplying window are proposed in the last part of frequency spectrum analysis.Finally the FFT spectrum analysis is realized on the DSK of TMS320C6000(6711),the experimental results are good.