1 files changed, 49 insertions, 0 deletions
diff --git a/filters.c b/filters.c
new file mode 100644
index 0000000..2bf9253
--- /dev/null
+++ b/filters.c
@@ -0,0 +1,49 @@
+/*
+vox - a musical real-time vocoder. version 1.0
+Copyright (C) 2000  Simon MORLAT (simon.morlat@free.fr)
+
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; either version 2
+of the License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+*/
+
+
+
+void lpc_filter(double *buf_ppf, double *lpc_coef, double *buf_sy, int n)
+{
+  int i,j;
+  double acc;
+
+  for(i=0;i<n;i++)
+  {
+      acc=buf_ppf[i]*lpc_coef[0];
+      for(j=1;j<11;j++)
+      {
+	  acc=acc-lpc_coef[j]*buf_sy[i-j];
+      };
+      buf_sy[i]=acc;
+  };
+}
+
+void hp_filter(double *in,double cut,int n)
+{
+  int i;
+  double prev_e,s_out;
+  prev_e=s_out=0;
+  for(i=0;i<n;i++)
+  {
+      s_out=in[i]-prev_e+cut*s_out;
+      prev_e=in[i];
+      in[i]=s_out;
+  };
+}