@thi.ng/dsp/power.js

Composable signal generators, oscillators, filters, FFT, spectrum, windowing & related DSP utils

import { isNumber } from "@thi.ng/checks/is-number";
import { isComplex } from "./complex.js";
const integralT = (window) => {
  let sum = 0;
  for (let i = window.length; i-- > 0; ) {
    sum += window[i];
  }
  return sum;
};
const integralTSquared = (window) => {
  let sum = 0;
  for (let i = window.length; i-- > 0; ) {
    sum += window[i] ** 2;
  }
  return sum;
};
const integralF = ([real, img]) => {
  let sum = 0;
  for (let i = real.length; i-- > 0; ) {
    sum += Math.hypot(real[i], img[i]);
  }
  return sum;
};
const integralFSquared = ([real, img]) => {
  let sum = 0;
  for (let i = real.length; i-- > 0; ) {
    sum += real[i] ** 2 + img[i] ** 2;
  }
  return sum;
};
const powerScale = (scale, base = 1) => isNumber(scale) ? scale : base / integralT(scale);
const invPowerScale = (scale, base = 1) => isNumber(scale) ? scale : integralT(scale) / base;
const powerSumSquared = (window) => isComplex(window) ? integralFSquared(window) / window[0].length : integralTSquared(window);
const powerMeanSquared = (window) => powerSumSquared(window) / (isComplex(window) ? window[0].length : window.length);
const powerTimeIntegral = (window, fs) => (isComplex(window) ? integralFSquared(window) : integralTSquared(window)) / fs;
export {
  integralF,
  integralFSquared,
  integralT,
  integralTSquared,
  invPowerScale,
  powerMeanSquared,
  powerScale,
  powerSumSquared,
  powerTimeIntegral
};