dsp-collection/signal/AdaptiveStft.js

A collection of JavaScript modules for digital signal processing (written in TypeScript)

import Complex from "../math/Complex.js";
import * as Goertzel from "./Goertzel.js";
import * as WindowFunctions from "./WindowFunctions.js";
export function getSingle_relWindow(samples, roughFrequency, roughWindowCenterPosition, relWindowWidth, windowFunction) {
    if (roughFrequency <= 0 || roughFrequency >= 0.5 || relWindowWidth < 1) {
        return;
    }
    if (!Number.isInteger(relWindowWidth)) {
        throw new Error("Parameter relWindowWidth is not an integer.");
    }
    const windowWidth = Math.round(relWindowWidth / roughFrequency);
    const windowStartPosition = Math.round(roughWindowCenterPosition - windowWidth / 2);
    if (windowStartPosition < 0 || windowStartPosition + windowWidth > samples.length) {
        return;
    }
    const windowSamples = samples.subarray(windowStartPosition, windowStartPosition + windowWidth);
    const windowedSamples = windowFunction ? WindowFunctions.applyWindow(windowSamples, windowFunction) : windowSamples;
    const component0 = Goertzel.goertzelSingle(windowedSamples, relWindowWidth);
    const componentNormalized = component0.mulReal(2 / windowWidth);
    const componentPhaseAdjusted = (relWindowWidth % 2 == 1) ? componentNormalized.neg() : componentNormalized;
    return {
        component: componentPhaseAdjusted,
        frequency: relWindowWidth / windowWidth,
        windowStartPosition: windowStartPosition,
        windowWidth: windowWidth
    };
}
export function getSingle_maxWindow(samples, roughFrequency, roughWindowCenterPosition, maxWindowWidth, windowFunction) {
    const relWindowWidth = Math.floor(maxWindowWidth * roughFrequency);
    return getSingle_relWindow(samples, roughFrequency, roughWindowCenterPosition, relWindowWidth, windowFunction);
}
export function getSingle(samples, roughFrequency, windowFunction) {
    const r = getSingle_maxWindow(samples, roughFrequency, samples.length / 2, samples.length, windowFunction);
    return r ? r.component : Complex.NaN;
}
export function getHarmonicAmplitudes(samples, windowCenterPosition, f0, harmonics, relWindowWidth = 7, windowFunction = WindowFunctions.flatTopWindowNorm) {
    if (!isFinite(f0) || f0 <= 0 || harmonics <= 0) {
        return;
    }
    if (!Number.isInteger(relWindowWidth)) {
        throw new Error("Parameter relWindowWidth is not an integer.");
    }
    const windowWidth = Math.round(relWindowWidth / f0);
    const windowStartPosition = Math.round(windowCenterPosition - windowWidth / 2);
    if (windowStartPosition < 0 || windowStartPosition + windowWidth > samples.length || windowWidth <= 0) {
        return;
    }
    const windowSamples = samples.subarray(windowStartPosition, windowStartPosition + windowWidth);
    const windowedSamples = WindowFunctions.applyWindow(windowSamples, windowFunction);
    const amplitudes = new Float64Array(harmonics);
    for (let harmonic = 1; harmonic <= harmonics; harmonic++) {
        const c = Goertzel.goertzelSingle(windowedSamples, harmonic * relWindowWidth);
        const amplitude = c.abs() * 2 / windowWidth;
        amplitudes[harmonic - 1] = amplitude;
    }
    return amplitudes;
}
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