Resumo

NUNEZ, R.. Obtención eficiente de espectros basada en un algoritmo mejorado de ventana ajustable. Rev. mex. fís. E [online]. 2007, vol.53, n.1, pp.20-30. ISSN 1870-3542.

The improved algorithm can produce a more accurate spectrum than the sines windows and the FFT, because reduces the spectral leakage only of signals that need it; very different situation with the sines windows and the FFT utilization. The cited algorithm is based on acquired signal fundamental frequency calculation and right adjusting of the sampling frequency by software via decimation and interpolation techniques, in order to obtain a rectangular window wide with a complete number of signal periods. For to develop the improved algorithm, first is taken the algorithm of Hidalgo, et al. (2002) like reference, which was developed in the C language, then is developed again in MATLAB6.5 language and his spectral results showed to be deficients for the polyharmonics signals case. Therefore, in the present paper, we do the procedures to solve these deficiency problems. Therefore, the new algorithm is called improved algorithm (IA), which shows, in base to several achieved tests, that is more efficiently than the reference one. Finally, the mixed signals spectrum of the IA was validated by the Dadisp software of DSP, Co., and the algorithm could be used to look for masking frequencies and signals identification with leakage spectrum.

Palavras-chave : DFT/FFT; spectral leakage; weighting windows; decimation; interpolation.

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