Fix RTA peak hold and FFT band energy

2026-07-22 08:42:32 +02:00
parent caec1edfcf
commit 3a0bdbb5ad
13 changed files with 394 additions and 87 deletions
@@ -0,0 +1,26 @@
+import assert from 'node:assert/strict';
+import { buildBandBinMapping, computeBandLevels } from '../www/core/utils.js';
+
+const band = [{ center: 1000, fLo: 875, fHi: 1125 }];
+
+for (const binCount of [2048, 4096, 8192, 16384]) {
+  const nyquist = 24000;
+  const binWidth = nyquist / binCount;
+  const mapping = buildBandBinMapping(band, nyquist, binCount);
+  const totalWeight = mapping[0].bins.reduce((sum, bin) => sum + bin.weight, 0);
+  assert.ok(
+    Math.abs(totalWeight * binWidth - 250) < 1e-6,
+    `bin overlaps must cover the complete band at FFT size ${binCount * 2}`,
+  );
+
+  // Constant power density: every bin contains density × bin width. The
+  // integrated band level must therefore be independent of FFT resolution.
+  const binPower = binWidth * 1e-6;
+  const binsDb = new Float32Array(binCount);
+  binsDb.fill(10 * Math.log10(binPower));
+  const level = computeBandLevels(mapping, binsDb)[0];
+  const expected = 10 * Math.log10(250e-6);
+  assert.ok(Math.abs(level - expected) < 1e-5, `FFT size ${binCount * 2}: ${level} vs ${expected}`);
+}
+
+console.log('FFT band-energy regression tests passed');