Added computing of PSD - Power Spectral Density for spectrum chart

Author: demvlad

src/graph_spectrum_calc.js

@@ -110,11 +110,11 @@ GraphSpectrumCalc.dataLoadPSD = function(analyserZoomY) {
   const flightSamples = this._getFlightSamplesFreq(false);
 
   let pointsPerSegment = 512;
-  const multiplier = Math.floor(1 / analyserZoomY); // 0. ... 10
+  const multipiler = Math.floor(1 / analyserZoomY); // 0. ... 10
   if (multipiler == 0) {
     pointsPerSegment = 256;
-  } else if (multiplier > 1) {
-    pointsPerSegment *= 2 ** Math.floor(multiplier / 2);
+  } else if (multipiler > 1) {
+    pointsPerSegment *= 2 ** Math.floor(multipiler / 2);
   }
   pointsPerSegment = Math.min(pointsPerSegment, flightSamples.samples.length);
   const overlapCount = Math.floor(pointsPerSegment / 2);
@@ -561,7 +561,7 @@ GraphSpectrumCalc._psd  = function(samples, pointsPerSegment, overlapCount, scal
       psdOutput: new Float64Array(0),
       min: 0,
       max: 0,
-      maxNoiseIdx: 0
+      maxNoiseIdx: 0,
     };
   }
   const maxFrequency = (this._blackBoxRate / 2.0);