Comparison of Walsh and Fourier spectroscopy of geomagnetic reversals and nonsinusoidal palaeoclimatic time series

Journal Article · Fri Jan 01 04:00:00 EST 1993 · IEEE Transactions on Geoscience and Remote Sensing (Institute of Electrical and Electronics Engineers); (United States)

DOI:https://doi.org/10.1109/36.210453· OSTI ID:6523178

Negi, J G; Tiwari, R K; Rao, K N.N. ^[1]

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1. National Geophysics Research Inst., Hyderabad (India)

Higher resolving capabilities and theoretical appropriateness of Walsh spectral techniques as compared to fourier spectral analyses are presented for synthetic and nonsinusoidal geotime series. Walsh functions form a complete orthogonal set of rectangular wave-functions assuming only two amplitude values of +1 and [minus]1 and possessing many other properties similar to Sine and Cosine functions. Theoretical development of Walsh transform techniques and a comparative study of Walsh and Fourier spectral estimates are presented. The Walsh spectral technique is applied specifically to two actual time series data of: (1) geomagnetic reversals in binary telegraphic wave form and (2) nonsinusoidal paleomagnetic and paleoclimate time series. Walsh spectra reveal periodicities in Milankovitch frequency bands and provide exceptionally well-resolved spectral lines. The possible physical significance of these orbital periodicities are discussed. A comparative example of autocorrelation analysis in real time domain and dyadic time domain is also presented using a telegraphic signal model of actual geomagnetic reversals time series and the result is briefly discussed. The computational efficiency of the Walsh function could be exploited further for many other binary and nonsinusoidal geophysical/geological time series.

• OSTI ID: 6523178
• Journal Information: IEEE Transactions on Geoscience and Remote Sensing (Institute of Electrical and Electronics Engineers); (United States), Journal Name: IEEE Transactions on Geoscience and Remote Sensing (Institute of Electrical and Electronics Engineers); (United States) Vol. 31:1; ISSN 0196-2892; ISSN IGRSD2
• Country of Publication: United States
• Language: English

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FREQUENCY ANALYSIS
FUNCTIONS
GEOLOGIC AGES
GEOLOGIC STRATA
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
MAGNETISM
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MULTIVARIATE ANALYSIS
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SPECTROSCOPY
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