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  1. /*
  2. * Atpdec
  3. * Copyright (c) 2003 by Thierry Leconte (F4DWV)
  4. *
  5. * $Id$
  6. *
  7. * This library is free software; you can redistribute it and/or modify
  8. * it under the terms of the GNU Library General Public License as
  9. * published by the Free Software Foundation; either version 2 of
  10. * the License, or (at your option) any later version.
  11. *
  12. * This program is distributed in the hope that it will be useful,
  13. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15. * GNU Library General Public License for more details.
  16. *
  17. * You should have received a copy of the GNU Library General Public
  18. * License along with this library; if not, write to the Free Software
  19. * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20. *
  21. */
  22. #include <filter.h>
  23. float fir( float *buff, const float *coeff, const int len)
  24. {
  25. int i;
  26. double r;
  27. r=0.0;
  28. for(i=0;i<len;i++) {
  29. r+=buff[i]*coeff[i];
  30. }
  31. return r;
  32. }
  33. void iqfir( float *buff, const float *Icoeff, const float *Qcoeff, const int len, float *Iptr,float *Qptr)
  34. {
  35. int i;
  36. float I,Q;
  37. I=Q=0.0;
  38. for(i=0;i<len;i++) {
  39. double v;
  40. v=buff[i];
  41. I+=v*Icoeff[i];
  42. Q+=v*Qcoeff[i];
  43. }
  44. *Iptr=I;
  45. *Qptr=Q;
  46. }
  47. float rsfir(float *buff,const float *coeff,const int len , const double offset , const double delta)
  48. {
  49. int i;
  50. double n;
  51. double out;
  52. out=0.0;
  53. for(i=0,n=offset;n<len-1;n+=delta,i++) {
  54. int k;
  55. double alpha;
  56. k=(int)n;
  57. alpha=n-k;
  58. out+=buff[i]*(coeff[k]*(1.0-alpha)+coeff[k+1]*alpha);
  59. }
  60. return out;
  61. }
  62. double iir(double x,iirbuff_t *buff,const iircoeff_t *coeff)
  63. {
  64. buff->x[4]=buff->x[3];
  65. buff->x[3]=buff->x[2];
  66. buff->x[2]=buff->x[1];
  67. buff->x[1]=buff->x[0];
  68. buff->x[0]=x/coeff->G;
  69. buff->y[2]=buff->y[1];
  70. buff->y[1]=buff->y[0];
  71. buff->y[0] = buff->x[4]
  72. + coeff->x[2] * buff->x[3]
  73. + coeff->x[1] * buff->x[2]
  74. + coeff->x[0] * buff->x[1]
  75. + buff->x[0]
  76. + coeff->y[1] * buff->y[2]
  77. + coeff->y[0] * buff->y[1];
  78. return (buff->y[0]);
  79. }