how to play tremolo effect?

[surikov]

Launch example https://playcode.io/1035150

Code

function playTremolo(){
  var selectedPreset=_tone_0010_SoundBlasterOld_sf2;
    var AudioContextFunc = window.AudioContext || window.webkitAudioContext;
    var audioContext = new AudioContextFunc();
    var player=new WebAudioFontPlayer();
  var pitch=12*4+7;
  var volume=0.75;
  var duration=1;
  var when=audioContext.currentTime + 0;
  var slides=[
    { delta: 0.5, when: 0.05 }
    ,{ delta: -0.5, when: 0.1 }
      ,{ delta: 0.5, when: 0.15 }
      ,{ delta: -0.5, when: 0.2 }
      ,{ delta: 0.5, when: 0.25 }
      ,{ delta: -0.5, when: 0.3 }
      ,{ delta: 0.5, when: 0.35 }
      ,{ delta: -0.5, when: 0.4 }
      ,{ delta: 0.5, when: 0.45 }
      ,{ delta: -0.5, when: 0.5 }
      ,{ delta: 0.5, when: 0.55 }
      ,{ delta: -0.5, when: 0.6 }
      ,{ delta: 0.5, when: 0.65 }
      ,{ delta: -0.5, when: 0.7 }
      ,{ delta: 0.5, when: 0.75 }
      ,{ delta: -0.5, when: 0.8 }
      ,{ delta: 0.5, when: 0.85 }
      ,{ delta: -0.5, when: 0.9 }
      ,{ delta: 0.5, when: 0.95 }
    ];
  var audioBufferSourceNode = player.queueWaveTable(audioContext
    , audioContext.destination
    , selectedPreset
    , when
    , pitch
    , duration
    , volume
    , slides
    );
}