{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,4]],"date-time":"2026-02-04T16:16:43Z","timestamp":1770221803109,"version":"3.49.0"},"reference-count":33,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2026,2,2]],"date-time":"2026-02-02T00:00:00Z","timestamp":1769990400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"FCT\u2014Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia, I.P."},{"DOI":"10.13039\/501100015494","name":"Instituto de Telecomunica\u00e7\u00f5es","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100015494","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Metrology"],"abstract":"<jats:p>Accurate and efficient frequency estimation is essential in many scientific fields and has led to the development of various algorithms. Commonly used methods involve applying the Discrete Fourier Transform followed by spectral interpolation. This approach faces challenges especially under low signal-to-noise ratio conditions. To mitigate this limitation, the Generalized Fractional Interpolated Discrete Fourier Transform for frequency estimation of rectangular-windowed sinewaves is proposed. This non-iterative algorithm enhances frequency estimation by employing spectral components at fractional steps of the Discrete Fourier Transform frequency resolution. A non-iterative, closed-form equation for frequency estimation is derived, enabling efficient computation. The proposed algorithm is evaluated through numerical simulations and compared with existing interpolation methods for different frequencies, signal-to-noise ratios, and number of acquired samples. The method is validated using experimentally acquired sinewave signals.<\/jats:p>","DOI":"10.3390\/metrology6010008","type":"journal-article","created":{"date-parts":[[2026,2,3]],"date-time":"2026-02-03T10:48:01Z","timestamp":1770115681000},"page":"8","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Generalized Fractional Interpolated Discrete Fourier Transform with Rectangular Window for Frequency Estimation in Noisy Sinewave Signals"],"prefix":"10.3390","volume":"6","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6005-2844","authenticated-orcid":false,"given":"Fernando M.","family":"Janeiro","sequence":"first","affiliation":[{"name":"Instituto de Telecomunica\u00e7\u00f5es, Escola de Ci\u00eancias e Tecnologia, Universidade de \u00c9vora, Largo dos Colegiais 2, 7004-516 \u00c9vora, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8914-9781","authenticated-orcid":false,"given":"Pedro M.","family":"Ramos","sequence":"additional","affiliation":[{"name":"Instituto de Telecomunica\u00e7\u00f5es, Instituto Superior T\u00e9cnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2333","DOI":"10.1109\/TCOMM.2018.2886355","article-title":"Fast and Efficient Sinusoidal Frequency Estimation by Using the DFT Coefficients","volume":"67","author":"Serbes","year":"2019","journal-title":"IEEE Trans. Commun."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"40230","DOI":"10.1109\/ACCESS.2022.3145913","article-title":"DFT-Based Frequency Estimation of Multiple Sinusoids","volume":"10","author":"Liu","year":"2022","journal-title":"IEEE Access"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"583","DOI":"10.2478\/v10178-011-0056-6","article-title":"Estimation of the amplitude square using the interpolated discrete Fourier transform","volume":"18","year":"2011","journal-title":"Metrol. Meas. 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