Least-squares_spectral_analysis

# Least-squares spectral analysis  ## Microsims — p5.js ### Least-squares spectral analysis (p5.js) · `LSSA` <div class="microsim-player"> <iframe src="https://editor.p5js.org/sciencenibber/full/h0z2TzuUv" width="100%" height="480" frameborder="0" loading="lazy" sandbox="allow-scripts allow-same-origin" title="Least-squares spectral analysis — p5.js microsim"></iframe> </div> *Find a spectrum by fitting sinusoids in the least-squares sense — works on unevenly sampled data where the FFT can't.* **Open in the editor:** [▶ fork this sketch](https://editor.p5js.org/sciencenibber/sketches/h0z2TzuUv) · movement *II · Transforms & the frequency domain* · library `p5js` ### Related microsims Live sims on neighbouring articles — 6 of them inside this article's own Wikipedia link tree: - [[Autocorrelation]] *(in tree)* - [[Calculus]] *(in tree)* - [[Complex_analysis]] *(in tree)* - [[Decibel]] *(in tree)* - [[Fast_Fourier_transform]] *(in tree)* - [[Fourier_analysis]] *(in tree)* *Sim hosted off-article; the article owns the reference, not the runtime (WIKI_RULES §10.4). 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least-squares sense, rather than by a Fourier transform. ## How it works / why it matters For each trial frequency, sine and cosine terms are fitted to minimize the squared residual, and the reduction in residual variance gives the spectral power at that frequency. Because it does not assume uniform sampling, LSSA handles unevenly or sparsely sampled data — a common situation in astronomy and geophysics — where the ordinary DFT fails. The widely used Lomb–Scargle periodogram is the standard implementation of this idea. ## Signs & universals Instantiates: spectrum, frequency, signal. ## Related Spectral estimation · Prony's method · Power spectral density · [[Fourier_analysis]] · Discrete Fourier transform · Fourier transform   *Built to the [[WT!P5_js_Microsim_Master_Class|p5.js Master Class]].*  ## Wikipedia : Wikitube **Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Least-squares_spectral_analysis) : [Wikitube](https://en.wikitube.io/wiki/Least-squares_spectral_analysis) ## Previous hub tags Tree parents: [[Monte_Carlo_method]] · [[Reliability_engineering]]. Legacy hubs: none. --- *Sources: 1 legacy note. Minted wave 1, 2026-07-30 (v1.6 order).*