HelpSource/Classes/PeakFollower.schelp

   1 class:: PeakFollower
   2 summary:: Track peak signal amplitude.
   3 related:: Classes/Peak
   4 categories::  UGens>Analysis>Amplitude
   5
   6
   7 Description::
   8
   9 Outputs the peak amplitude of the signal received at the input. If level
  10 is below maximum, the level decreases by the factor given in
  11 code::decay:: .
  12
  13
  14 Internally, the absolute value of the signal is used, to prevent
  15 underreporting the peak value if there is a negative DC offset. To obtain
  16 the minimum and maximum values of the signal as is, use the
  17 link::Classes/RunningMin::  and  link::Classes/RunningMax::  UGens.
  18
  19
  20 classmethods::
  21
  22 method::ar, kr
  23
  24 argument::in
  25
  26 The input signal.
  27
  28
  29 argument::decay
  30
  31 Decay factor.
  32
  33
  34 Examples::
  35
  36 code::
  37
  38 s.boot;
  39
  40 // no decay
  41 (
  42 {
  43         SinOsc.ar(
  44                         PeakFollower.ar(Dust.ar(20, Line.kr(0, 1, 4)), 1.0) * 1500 + 200,
  45                         0, 0.2
  46         )
  47
  48 }.play;
  49 )
  50
  51 // a little decay
  52 (
  53 {
  54         SinOsc.ar(
  55                         PeakFollower.ar(Dust.ar(20, Line.kr(0, 1, 4)), 0.999) * 1500 + 200,
  56                         0, 0.2
  57         )
  58
  59 }.play;
  60 )
  61
  62 // mouse x controls decay, center of the
  63 (
  64 {
  65         var decay;
  66         decay = MouseX.kr(0.99, 1.00001).min(1.0);
  67         SinOsc.ar(
  68                         PeakFollower.ar(Dust.ar(20), decay) * 1500 + 200,
  69                         0, 0.2
  70         );
  71
  72 }.play;
  73 )
  74
  75
  76
  77
  78 // follow a sine lfo, decay controlled by mouse x
  79 (
  80 {
  81         var decay;
  82         decay = MouseX.kr(0, 1.1).min(1.0);
  83         SinOsc.ar(
  84                         PeakFollower.kr(SinOsc.kr(0.2), decay) * 200 + 500,
  85                         0, 0.2
  86         )
  87
  88 }.play;
  89 )
  90
  91 ::
  92