Universal Short-Time Fourier Transform: Data-Adaptive Window-Length Selection for Time-Frequency Analysis
Abstract
The short-time Fourier transform (STFT) characterizes the local frequency content of time-varying signals by evaluating the discrete Fourier transform over a sliding analysis window. The STFT is governed by a fundamental resolution trade-off: a short window localizes rapid transients in time at the cost of frequency resolution, whereas a long window resolves closely spaced harmonics at the expense of temporal resolution. The Universal Short-Time Fourier Transform (U-STFT) resolves this trade-off sequentially by modeling the analysis window duration as a data-adaptive state variable that indexes the number of hops included in the current observation interval. At each frame, a bank of candidate window durations is scored using normalized order-three Rényi entropy to quantify joint time-frequency concentration. A window length trellis aggregates the resulting 𝒪(3M) candidate window schedules with linear complexity per frame, guaranteeing a cumulative mix-loss regret bound of 𝒪((k+1)log M) relative to any hindsight window schedule with k resolution changes over M frames. By linearity of the Fourier transform, posterior expectation across the candidate bank yields a single spectrum equivalent to an STFT evaluated with a data-adaptive effective window, while an envelope-normalized synthesis stream guarantees exact overlap-add reconstruction. Evaluations on synthetic and marine bioacoustic signals demonstrate adaptive resolution tracking, enhanced spectral concentration, and exact time-domain invertibility.
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BibTeX
@misc{mittal2026universal,
title = {{Universal Short-Time Fourier Transform: Data-Adaptive Window-Length Selection for Time-Frequency Analysis}},
author = {Manan Mittal and Kanad Sarkar and Ryan M. Corey and John R. Buck and Andrew C. Singer},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.37795},
eprint = {2610.37795},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.37795},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Universal Short-Time Fourier Transform: Data-Adaptive Window-Length Selection for Time-Frequency Analysis
AU - Manan Mittal
AU - Kanad Sarkar
AU - Ryan M. Corey
AU - John R. Buck
AU - Andrew C. Singer
PY - 2026
DA - 2026/10/27
PB - arXiv
DO - 10.48550/arxiv.2610.37795
UR - https://arxiv.org/abs/2610.37795
AB - The short-time Fourier transform (STFT) characterizes the local frequency content of time-varying signals by evaluating the discrete Fourier transform over a sliding analysis window. The STFT is governed by a fundamental resolution trade-off: a short window localizes rapid transients in time at the cost of frequency resolution, whereas a long window resolves closely spaced harmonics at the expense of temporal resolution. The Universal Short-Time Fourier Transform (U-STFT) resolves this trade-off sequentially by modeling the analysis window duration as a data-adaptive state variable that indexes the number of hops included in the current observation interval. At each frame, a bank of candidate window durations is scored using normalized order-three Rényi entropy to quantify joint time-frequency concentration. A window length trellis aggregates the resulting 𝒪(3^M) candidate window schedules with linear complexity per frame, guaranteeing a cumulative mix-loss regret bound of 𝒪((k+1)log M) relative to any hindsight window schedule with k resolution changes over M frames. By linearity of the Fourier transform, posterior expectation across the candidate bank yields a single spectrum equivalent to an STFT evaluated with a data-adaptive effective window, while an envelope-normalized synthesis stream guarantees exact overlap-add reconstruction. Evaluations on synthetic and marine bioacoustic signals demonstrate adaptive resolution tracking, enhanced spectral concentration, and exact time-domain invertibility.
ER -