From d6b088044e161a27d49df537bbb6d998a8d0e50d Mon Sep 17 00:00:00 2001 From: musil Date: Sat, 9 Dec 2006 02:00:52 +0000 Subject: // class_sethelpsymbol(); changed help-*.pd to *-help.pd chanded file structure to standard 1st step remove old svn path=/trunk/externals/iemlib/; revision=6756 --- iemlib1/src/biquad_freq_resp.c | 86 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 86 insertions(+) create mode 100644 iemlib1/src/biquad_freq_resp.c (limited to 'iemlib1/src/biquad_freq_resp.c') diff --git a/iemlib1/src/biquad_freq_resp.c b/iemlib1/src/biquad_freq_resp.c new file mode 100644 index 0000000..e95a84c --- /dev/null +++ b/iemlib1/src/biquad_freq_resp.c @@ -0,0 +1,86 @@ +/* For information on usage and redistribution, and for a DISCLAIMER OF ALL +* WARRANTIES, see the file, "LICENSE.txt," in this distribution. + +iemlib1 written by Thomas Musil, Copyright (c) IEM KUG Graz Austria 2000 - 2006 */ + + +#include "m_pd.h" +#include "iemlib.h" +#include + +/* ------------------------ biquad_freq_resp ------------------- */ +/* -- calculates the frequency responce of a biquad structure -- */ + +typedef struct _biquad_freq_resp +{ + t_object x_obj; + t_float a0; + t_float a1; + t_float a2; + t_float b1; + t_float b2; + t_outlet *x_out_re; + t_outlet *x_out_im; +} t_biquad_freq_resp; + +static t_class *biquad_freq_resp_class; + +static void biquad_freq_resp_float(t_biquad_freq_resp *x, t_floatarg f) +{ + t_float re1, im1, re2, im2; + t_float c, s, a; + + if(f < 0.0f) + f = 0.0f; + else if(f > 180.0f) + f = 180.0; + f *= 3.14159265f; + f /= 180.0f; + + c = cos(f); + s = sin(f); + + re1 = x->a0 + x->a1*c + x->a2*(c*c - s*s); + im1 = x->a1*s + x->a2*2.0f*(s*c); + re2 = 1.0f - x->b1*c - x->b2*(c*c - s*s); + im2 = -x->b1*s - x->b2*2.0f*(s*c); + a = re2*re2 + im2*im2; + outlet_float(x->x_out_im, (re1*im2 - re2*im1)/a);/* because z^-1 = e^-jwt, negative sign */ + outlet_float(x->x_out_re, (re1*re2 + im1*im2)/a); + +} +/* y/x = (a0 + a1*z-1 + a2*z-2)/(1 - b1*z-1 - b2*z-2);*/ + +static void biquad_freq_resp_list(t_biquad_freq_resp *x, t_symbol *s, int argc, t_atom *argv) +{ + if((argc == 5)&&IS_A_FLOAT(argv,4)&&IS_A_FLOAT(argv,3)&&IS_A_FLOAT(argv,2)&&IS_A_FLOAT(argv,1)&&IS_A_FLOAT(argv,0)) + { + x->b1 = (float)atom_getfloatarg(0, argc, argv); + x->b2 = (float)atom_getfloatarg(1, argc, argv); + x->a0 = (float)atom_getfloatarg(2, argc, argv); + x->a1 = (float)atom_getfloatarg(3, argc, argv); + x->a2 = (float)atom_getfloatarg(4, argc, argv); + } +} + +static void *biquad_freq_resp_new(void) +{ + t_biquad_freq_resp *x = (t_biquad_freq_resp *)pd_new(biquad_freq_resp_class); + x->x_out_re = outlet_new(&x->x_obj, &s_float); + x->x_out_im = outlet_new(&x->x_obj, &s_float); + x->b1 = 0.0f; + x->b2 = 0.0f; + x->a0 = 0.0f; + x->a1 = 0.0f; + x->a2 = 0.0f; + return (x); +} + +void biquad_freq_resp_setup(void) +{ + biquad_freq_resp_class = class_new(gensym("biquad_freq_resp"), (t_newmethod)biquad_freq_resp_new, 0, + sizeof(t_biquad_freq_resp), 0, 0); + class_addfloat(biquad_freq_resp_class, biquad_freq_resp_float); + class_addlist(biquad_freq_resp_class, (t_method)biquad_freq_resp_list); +// class_sethelpsymbol(biquad_freq_resp_class, gensym("iemhelp/help-biquad_freq_resp")); +} -- cgit v1.2.1