Perceiving harmonic information (especially weak harmonic information) in time series has important scientific and engineering significance. Fourier spectrum and time-frequency spectrum are commonly used tools for per...Perceiving harmonic information (especially weak harmonic information) in time series has important scientific and engineering significance. Fourier spectrum and time-frequency spectrum are commonly used tools for perceiving harmonic information, but they are often ineffective in perceiving weak harmonic signals because they are based on energy or amplitude analysis. Based on the theory of Normal time-frequency transform (NTFT) and complex correlation coefficient, a new type of spectrum, the Harmonicity Spectrum (HS), is developed to perceive harmonic information in time series. HS is based on the degree of signal harmony rather than energy or amplitude analysis, and can therefore perceive very weak harmonic information in signals sensitively. Simulation examples show that HS can detect harmonic information that cannot be detected by Fourier spectrum or time-frequency spectrum. Acoustic data analysis shows that HS has better resolution than traditional LOFAR spectrum.展开更多
An adaptive algorithm for extracting weak signal based on the theory of stochastic resonance(SR) was proposed. It was implemented by investigating the self correlation of the outputs of the bistable system(with differ...An adaptive algorithm for extracting weak signal based on the theory of stochastic resonance(SR) was proposed. It was implemented by investigating the self correlation of the outputs of the bistable system(with different μ ). The results show that the self correlation will reach maximum when a sudden change of output occurs, and hence prove that SR is sensitive sharply to the change of the parameters μ , and also provide one novel method to express the outputs which hasnt been solved till now. The adaptive algorithm was also applied to analyze the weak Laser Raman spectrum of a CCl 4 sample(liquid in capillary) which was measured with SPEX 1403 Laser Raman spectrometer from 250 cm -1 to 418 cm -1 on 5 mW(output power of laser) . The spectrum was analyzed with the adaptive algorithm by varying the data to (-4 13, 3 50) and declining μ from 2 0 with step 0 01. The results obtained show that the adaptive algorithm was able to detect the weak signal automatically and correctly.展开更多
文摘Perceiving harmonic information (especially weak harmonic information) in time series has important scientific and engineering significance. Fourier spectrum and time-frequency spectrum are commonly used tools for perceiving harmonic information, but they are often ineffective in perceiving weak harmonic signals because they are based on energy or amplitude analysis. Based on the theory of Normal time-frequency transform (NTFT) and complex correlation coefficient, a new type of spectrum, the Harmonicity Spectrum (HS), is developed to perceive harmonic information in time series. HS is based on the degree of signal harmony rather than energy or amplitude analysis, and can therefore perceive very weak harmonic information in signals sensitively. Simulation examples show that HS can detect harmonic information that cannot be detected by Fourier spectrum or time-frequency spectrum. Acoustic data analysis shows that HS has better resolution than traditional LOFAR spectrum.
文摘An adaptive algorithm for extracting weak signal based on the theory of stochastic resonance(SR) was proposed. It was implemented by investigating the self correlation of the outputs of the bistable system(with different μ ). The results show that the self correlation will reach maximum when a sudden change of output occurs, and hence prove that SR is sensitive sharply to the change of the parameters μ , and also provide one novel method to express the outputs which hasnt been solved till now. The adaptive algorithm was also applied to analyze the weak Laser Raman spectrum of a CCl 4 sample(liquid in capillary) which was measured with SPEX 1403 Laser Raman spectrometer from 250 cm -1 to 418 cm -1 on 5 mW(output power of laser) . The spectrum was analyzed with the adaptive algorithm by varying the data to (-4 13, 3 50) and declining μ from 2 0 with step 0 01. The results obtained show that the adaptive algorithm was able to detect the weak signal automatically and correctly.
