interpretor/faust-0.9.47mr3/examples/bandfilter.dsp

   1 declare name            "bandfilter";
   2 declare version         "1.0";
   3 declare author          "Grame";
   4 declare license         "BSD";
   5 declare copyright       "(c)GRAME 2006";
   6
   7 import("math.lib");
   8 import("music.lib");
   9
  10 //---------------------second order filter--------------------------
  11 // filter(Q,F,G)
  12 //                      Q : quality factor [1..100]
  13 //                              F :     frequency (Hz)
  14 //                              G : gain [0..1]
  15 //------------------------------------------------------------------
  16
  17 filter(Q,F,G)   = TF2(  (1 +  K/Q + K*K)        / D,
  18                                                  2 * (K*K - 1)          / D,
  19                                                 (1 - K/Q + K*K)         / D,
  20                                                  2 * (K*K - 1)          / D,
  21                                                 (1 - V*K/Q + K*K)       / D
  22                                          )
  23                 with {
  24                                 V = db2linear(G);
  25                                 K = tan(PI*F/SR);
  26                                 D = 1 + V*K/Q + K*K;
  27                 };
  28
  29
  30
  31 //--------------- Band Filter with user interface ------------------
  32 // bandfilter(F)
  33 //                      F :     default frequency (Hz)
  34 //
  35 //------------------------------------------------------------------
  36
  37 bandfilter(F)   = filter(       nentry("Q factor [style:knob]",50,0.1,100,0.1),
  38                                                         nentry("freq [unit:Hz][style:knob]", F, 20, 20000, 1),
  39                                                         0 - vslider("gain [unit:dB]", 0, -50, 50, 0.1)
  40                                                 );
  41
  42
  43
  44 //------------------------- Process --------------------------------
  45
  46 process                 = vgroup("Bandfilter", bandfilter(1000));
  47