FFT Algorithm Optimization And The Realization Of DSP

Signal processing methods are the important technical foundation of current mechanical equipment fault diagnosis, the analysis results are the key factor in accuracy of the diagnosis. On the spectrum of correction methods and error analysis, improving the accuracy of spectral analysis method is one of the main direction of development.This paper reviews the current system of internal transformation of the FFT spectrum correction after the four methods. The first is the Amplitude Spectrum of the Ratio Correction, this approach useing of a margin after a function of the ratio of two spectrum, the establishment of a correction to the frequency of variable equation of the frequency and then the amplitude and phase correction. The second is Energy Centrobaric Correction Method, this paper demonstrates that the energy centroid of discrete spectrum of frequently used windows is near the origin of coord -inate and deduces the correction formula of frequency and phase using Energy Centrobaric Correcting Method. The third is Phase Difference Correcting Method for Calibration, this method including time-domain translation and the change of window width,the second time-domain sequence lags behind the first one with L points,performing N point FFT analysis on the first sequence and M-point FFT analysis on the second one,and finally correcting spectrum by making use of the phase difference of two corresponding peak lines. The fourth is Zoom FFT+FT Spectrum by Fourier Transform,the method get the precise value of some main frequency,and thus greatly improve the frequency discrimation of FFT spectrum.Error analysis and simulation results show that the Ratio Correction method for resolving the precise extent after the FFT, frequency and phase for the accurate measurement of signal parameters provides an effective means; Correction For The Amplitude Error In FFT By Two Window Funtions -A window function which has a flat top in frequency domain is designed to correct the amplitude error caused by Picket-Fence effect.The window function has a wide main lobe,which results in a loss of frequency resolution of the spectrum.To correct the amplitude error and still keep a high frequency resolution in the FFT spectrum,a new algorithm is proposed,which uses two window functions to do spectrum analysis.The one is a rectangular window function and the other is a window function that has a flat top inrequency domain.By combination of the two window functions,a spectrum can be reached which has both the frequency resolution of rectangular window function and the amplitude resolution of the window function that has a flat top in frequency domain. the implememtation of FFT algorithm optimization on the DSP is introuduced.