Instantaneous Spectra Analysis of Pulse Series -- Application to Lung Sounds with Abnormalities

Fuente: arXiv
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Main Author: Ishiyama, Fumihiko
Format: Preprint
Published: 2026
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author Ishiyama, Fumihiko
author_facet Ishiyama, Fumihiko
contents The origin of the "theoretical limit of time-frequency resolution of Fourier analysis" is from its numerical implementation, especially from an assumption of "Periodic Boundary Condition (PBC)," which was introduced a century ago. We previously proposed to replace this condition with "Linear eXtrapolation Condition (LXC)," which does not require periodicity. This feature makes instantaneous spectra analysis of pulse series available, which replaces the short time Fourier transform (STFT). We applied the instantaneous spectra analysis to two lung sounds with abnormalities (crackles and wheezing) and to a normal lung sound, as a demonstration. Among them, crackles contains a random pulse series. The spectrum of each pulse is available, and the spectrogram of pulse series is available with assembling each spectrum. As a result, the time-frequency structure of given pulse series is visualized.
format Preprint
id arxiv_https___arxiv_org_abs_2602_03680
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Instantaneous Spectra Analysis of Pulse Series -- Application to Lung Sounds with Abnormalities
Ishiyama, Fumihiko
Physics and Society
Sound
The origin of the "theoretical limit of time-frequency resolution of Fourier analysis" is from its numerical implementation, especially from an assumption of "Periodic Boundary Condition (PBC)," which was introduced a century ago. We previously proposed to replace this condition with "Linear eXtrapolation Condition (LXC)," which does not require periodicity. This feature makes instantaneous spectra analysis of pulse series available, which replaces the short time Fourier transform (STFT). We applied the instantaneous spectra analysis to two lung sounds with abnormalities (crackles and wheezing) and to a normal lung sound, as a demonstration. Among them, crackles contains a random pulse series. The spectrum of each pulse is available, and the spectrogram of pulse series is available with assembling each spectrum. As a result, the time-frequency structure of given pulse series is visualized.
title Instantaneous Spectra Analysis of Pulse Series -- Application to Lung Sounds with Abnormalities
topic Physics and Society
Sound
url https://arxiv.org/abs/2602.03680