Design And Implementation Of Portable Spectrometer Based On FFT

Spectrum analyzer is widely used in the fields of production,life,teaching,scientific research,military and national defense,especially portable spectrum analyzer.Because of its convenience for real-time monitoring of spectrum information in certain specific frequency bands,it greatly improves work efficiency and becomes a research hotspot in the fields of radio monitoring,precision instrument production.In this paper,the working principle and process of spectrum analyzer were analyzed.A digital down conversion system based on optimized mixer was designed.A spectrum calculation algorithm based on adaptive FFT was proposed and implemented by software.Finally,a portable spectrum analyzer was realized.Specific research contents are as follows:(1)Aiming at the problem of high power consumption in traditional digital downconversion data processing,a digital down-conversion system based on optimized mixer was designed.By incorporating the mixer into the decimation filter bank,the distribution of the hardware resources of the FPGA is rearranged and the power consumption reduced.(2)To solve the problem of slow speed and inflexible use of single cardinality in calculating signal spectrum,an adaptive FFT spectrum calculation algorithm was proposed.By fusing multiple cardinalities and adding selection judgment mechanism,the least computational cardinality was automatically selected for spectrum calculation.It is proved that speeds up the speed of spectrum calculation and improves the real-time performance.(3)A customized portable spectrum analyzer was designed and implemented using the proposed algorithm.Compared with standard spectrum analyzer,the advantages of the system in power consumption and time are verified.