Research On Correction Methods Of Discrete Intensive Spectrum

There is a lot of signal composed of intensive or continuous frequency components in engineering, such as beat vibration signal that is one of the simplest intensive frequency signals. Correction technology of intensive spectrum need advanced study. The paper investigates the correction technology of discrete intensive spectrum.First, Based on an investigation of the amplitude errors in Fourier transform and spectrum analysis Produced by windowing, The paper introduces how to select a proper window to suppress fake frequency and improve the ratio of signal to noise. At the same time, the paper analyses the error of discrete spectrum analysis, that proves the necessary of spectrum correction, and discusses the impact of spectrum lines interference to the accuracy of spectrum correction. Secondly, after analyzing several existed methods of correction on discrete spectrum, using some utility procedure to realize simulation verify of correction methods on signal without noise, small noise and large noise. Afterwards, Based on the analysis of advantages and disadvantages of the ratio correction, the paper analyses the principle of identification of parameters in frequency domain and problems of correction in detail, take a detailed analysis of error, then extend the correction method using frequency decomposition on aliasing spectrum composed of two intensive frequency components to correct signal whose space of intensive frequency components within two frequency resolution- The paper extends the method of identification of parameters to identify intensive spectrum with two or more components. Finally, two widely used methods of zoom are introduced to supplement the shortage of the method of intensive spectrum correction, which are Chirp-Z transform and Zoom-FFT. In view of the Chirp-Z Transform's large amount of computation when there is a lot of signal data, this paper suggests a new method, based on SD-DFT, to partially refining spectrum with guarantee for the accuracy. Based on the theory, adaptive zoom and correction procedure is put forward in favor of practical application.