Diff: IIR_filter.cpp

Revision:

10:600d7cf652e7

Parent:

5:d6c7ccbbce78

Child:

17:e9e75de5fe32

--- a/IIR_filter.cpp	Thu Mar 22 17:34:18 2018 +0000
+++ b/IIR_filter.cpp	Thu Mar 29 19:15:31 2018 +0000
@@ -7,6 +7,7 @@
   init for: first order differentiatior:   G(s) = s/(T*s + 1)
             first order lowpass with gain  G(s) = K/(T*s + 1)
             second order lowpass with gain G(s) = K*w0^2/(s^2 + 2*D*w0*s + w0*w0)        
+            nth order, with arbitrary values
   the billinear transformation is used for s -> z
   reseting the filter only makes sence for static signals, whatch out if you're using the differnetiator
 */
@@ -87,6 +88,37 @@
     // dc-gain
     this->K = K;
 }
+
+IIR_filter::IIR_filter(float *b,float *a,int nb_, int na_){
+    
+    // filter orders
+    this->nb = nb_-1;    // Filter Order
+    this->na = na_;      // Filter Order
+    
+    // filter coefficients
+    B = (float*)malloc((nb+1)*sizeof(float));
+    A = (float*)malloc(na*sizeof(float));
+    uk = (float*)malloc((nb+1)*sizeof(float));
+    yk = (float*)malloc(na*sizeof(float));
+    
+    for(int k=0;k<=nb;k++){
+        B[k]=b[k];
+        uk[k]=0.0f;
+        }
+    for(int k=0;k<na;k++){
+        A[k] = a[k];
+        yk[k] = 0.0f;
+        }
+    //B[0] = K*k0/k2;
+    //B[1] = 2.0f*B[0];
+    //B[2] = B[0]; 
+    //A[0] = (2.0f*k0 - 8.0f)/k2;
+    //A[1] = (k0 - k1 + 4.0f)/k2;
+    
+    // dc-gain
+    this->K = 1.0f;
+}
+
     
 IIR_filter::~IIR_filter() {}