interpretor/faust-0.9.47mr3/tests/mathdoc/rms.dsp

   1 declare name            "rms";
   2 declare version         "1.0";
   3 declare author          "Grame";
   4 declare license         "BSD";
   5 declare copyright       "(c)GRAME 2009";
   6
   7
   8 // Root Mean Square of n consecutive samples
   9 RMS(n) = square : mean(n) : sqrt ;
  10
  11 // the square of a signal
  12 square(x) = x * x ;
  13
  14 // the mean of n consecutive samples of a signal
  15 // uses fixpoint to avoid the accumulation of
  16 // rounding errors
  17 mean(n) = float2fix : integrate(n) : fix2float : /(n);
  18
  19 // the sliding sum of n consecutive samples of a signal
  20 integrate(n,x) = x - x@n : +~_ ;
  21
  22 // convertion between float and fix point
  23 float2fix(x) = int(x*(1<<20));
  24 fix2float(x) = float(x)/(1<<20);
  25
  26 // Root Mean Square of 1000 consecutive samples
  27 process = RMS(1000) ;