noise floor

Author: ArdenButterfield

all-panels/index.html

@@ -44,6 +44,7 @@ <h2>Input</h2>
               <div class="slider" id="frequency-slider"></div>
               <div class="slider" id="num-harmonics-slider"></div>
               <div class="slider" id="amplitude-slider"></div>
+              <div class="slider" id="noise-floor-slider"></div>
             </div>
             <button class="play-button" id="play-input">Play</button>
           </div>

delta-sigma-panels/index.html

@@ -42,6 +42,7 @@ <h2>Input</h2>
           <div class="slider" id="frequency-slider"></div>
           <div class="slider" id="num-harmonics-slider"></div>
           <div class="slider" id="amplitude-slider"></div>
+          <div class="slider" id="noise-floor-slider"></div>
         </div>
         <button class="play-button" id="play-input">Play</button>
       </div>

slider.js

@@ -121,7 +121,7 @@ class AudioInputTypeSlider extends Slider{
   resize(x, y, w, p) {
     this.inputSelect.width = w / 3;
     this.oddEvenSel.width = w / 3;
-    this.inputSelect.position(x, y);
+    this.inputSelect. position(x, y);
     this.oddEvenSel.position(x + this.inputSelect.width,y);
     this.slopeSel.position(x + this.inputSelect.width + this.oddEvenSel.width,y);
   }
@@ -164,6 +164,31 @@ class FreqSlider extends RangedSlider{
   }
 }
 
+class NoiseFloorSlider extends RangedSlider {
+  setup(p,settings){
+    this.settings = settings;
+    this.name ="Noise floor (dB)";
+    this.propName = "noiseFloor";
+    this.min = -96;
+    this.max = 0 ;
+    this.initial = -96;
+    this.step = 1.0;
+    this.displayVal = this.initial;
+    this.makeSlider(p);
+  }
+
+  calcSliderVal(){
+    // override this with any calculations needed to convert textbox val to slider val (%, etc)
+    return this.textBox.value() === "-infinity" ? -96 : this.textBox.value();
+  }
+  calcDisplayVal(){
+    // override this with any calculations needed to convert stored variable to display val (%, etc)
+    return this.settings[this.propName] <= -96 ? "-infinity" : this.settings[this.propName];
+  }
+
+
+}
+
 class DeltaSigmaStepSlider extends RangedSlider {
   setup(p, settings) {
     this.settings = settings;

waves.js

@@ -227,6 +227,12 @@ function getSamples(settings, destination) {
       }
     }
   }
+  if (settings.noiseFloor > -96) {
+    const noiseGain = Math.pow(10, settings.noiseFloor / 20);
+    destination.forEach((x, n, arr) => {
+      arr[n] = x + (Math.random() * 2 - 1) * noiseGain;
+    });
+  }
 }
 
 function normalize(arr, targetAmplitude) {

widget.js

@@ -43,6 +43,7 @@ function getDefaultSettings() {
     , fundFreq: 1250 // input signal fundamental freq
     , sampleRate: WEBAUDIO_MAX_SAMPLERATE
     , downsamplingFactor: 2
+    , noiseFloor: -96
     , numHarm: 2 //Number of harmonics
     , harmType: "All" // Harmonic series to evaluate - Odd, even or all
     , harmSlope: "1/x" // Amplitude scaling for harmonics. can be used to create different shapes like saw or square
@@ -102,6 +103,7 @@ let sliderIdLookups = {
   'audio-input-type-slider' : AudioInputTypeSlider,
   'amplitude-slider' : AmplitudeSlider,
   'frequency-slider' : FreqSlider,
+  'noise-floor-slider' : NoiseFloorSlider,
   'num-harmonics-slider' : NumHarmSlider,
   'antialiasing-filter-order-slider': AntialiasingSlider,
   'filter-type-slider' : FilterTypeSlider,