[Commit-gnuradio] r11607 - gnuradio/branches/developers/n4hy/pfb_iir2/gnuradio-core/src/lib/general

[n4hy]

Author: n4hy
Date: 2009-08-17 11:44:39 -0600 (Mon, 17 Aug 2009)
New Revision: 11607

Modified:
   
gnuradio/branches/developers/n4hy/pfb_iir2/gnuradio-core/src/lib/general/gr_iirdes.cc
Log:
chebyshevord initially add, not tested

Modified: 
gnuradio/branches/developers/n4hy/pfb_iir2/gnuradio-core/src/lib/general/gr_iirdes.cc
===================================================================
--- 
gnuradio/branches/developers/n4hy/pfb_iir2/gnuradio-core/src/lib/general/gr_iirdes.cc
       2009-08-17 17:20:47 UTC (rev 11606)
+++ 
gnuradio/branches/developers/n4hy/pfb_iir2/gnuradio-core/src/lib/general/gr_iirdes.cc
       2009-08-17 17:44:39 UTC (rev 11607)
@@ -223,69 +223,52 @@
   switch (fresp) {
   case gr_iirdes::LOWPASS: {
     vector<double> rtn(2);
+    double Wa;
     if (Wp[0]>=Ws[0])
       throw std::invalid_argument ("For lowpass filter Wp < Ws");
 
     Ws[0] = tan(M_PI*Ws[0]);
     Wp[0] = tan(M_PI*Wp[0]);
-    rtn[0] = ceil(0.5*(qs - qp)/log(Ws[0]/Wp[0]));
-    rtn[1] = exp(log(Wp[0]) - qp/2/rtn[0]);    
-    rtn[1] = atan(rtn[1])/M_PI;
+    Wa = Ws[0]/Wp[0];
+    rtn[0] = ceil(acosh(sqrt((qs-1)/(qp-1)))/acosh(Wa));
+    rtn[1] = Wp[0];
     return rtn;
   }
   case gr_iirdes::HIGHPASS: {
+    double Wa;
     vector<double> rtn(2);
     if (Ws[0]>=Wp[0]) throw std::invalid_argument ("For highpass filter Wp > 
Ws");
-    Ws[0]= 0.5-Ws[0];
-    Wp[0]= 0.5-Wp[0];
     Ws[0] = tan(M_PI*Ws[0]);
     Wp[0] = tan(M_PI*Wp[0]);
-    rtn[0] = ceil(0.5*(qs - qp)/log(Ws[0]/Wp[0]));
-    rtn[1] = exp(log(Wp[0]) - qp/2/rtn[0]);    
-    rtn[1] = 0.5-atan(rtn[1])/M_PI;
+    Wa = Wp[0]/Ws[0];
+    rtn[0] = ceil(acosh(sqrt((qs-1)/(qp-1)))/acosh(Wa));
+    rtn[1] = Wp[0]
     return rtn;
   }
   case gr_iirdes::BANDPASS: {
+    double Wa[2];
     vector<double> rtn(3);
     if ((Ws[0]>=Wp[0]) ||
        (Wp[0]>=Wp[1]) ||
        (Wp[1]>=Ws[1])) throw std::invalid_argument
                          ("For bandpass filter Ws[0]<Wp[0]<Wp[1]<Ws[1]");
-    Ws[0] = tan(M_PI*(0.5-Ws[0]));
+
+    Ws[0] = tan(M_PI*Ws[0]);
+    Wp[0] = tan(M_PI*Wp[0]);
     Ws[1] = tan(M_PI*Ws[1]);
-    Wp[0] = tan(M_PI*(0.5-Wp[0]));
     Wp[1] = tan(M_PI*Wp[1]);
-    rtn[0] = ceil(fmax(0.5*(qs - qp)/log(Ws[0]/Wp[0]),
-                      0.5*(qs - qp)/log(Ws[1]/Wp[1]))/2.0);
-
-    rtn[1] = exp(log(Wp[0]) - qp/2/rtn[0]);    
-    rtn[2] = exp(log(Wp[1]) - qp/2/rtn[0]);
-
-    rtn[1] = 0.5-atan(rtn[1])/M_PI;
-    rtn[2] = atan(rtn[2])/M_PI;
-
+    for (int i=0;i<2;i++)
+      Wa[i]=(Ws[i]^2-Wp[0]*Wp[1])/(Ws[i]*(Wp[0]-Wp[1]));
+    Wa[0]=fmin(Wa[0],Wa[1]);
+    rtn[0] = ceil(acosh(sqrt((qs-1)/(qp-1)))/acosh(Wa[0]));
+    rtn[1]=Wp[0];
+    rtn[2]=Wp[1];
     return rtn;
   }
   case gr_iirdes::BANDSTOP: {
     vector<double> rtn(3);
-    if ((Wp[0]>=Ws[0]) ||
-       (Ws[0]>=Ws[1]) ||
-       (Ws[1]>=Wp[1])) throw std::invalid_argument
-                         ("For bandstop filter Wp[0]<Ws[0]<Ws[1]<Wp[1]");
-
-    Ws[0] = tan(M_PI*Ws[0]);
-    Ws[1] = tan(M_PI*(0.5-Ws[1]));
-    Wp[0] = tan(M_PI*Wp[0]);
-    Wp[1] = tan(M_PI*(0.5-Wp[1]));
-    rtn[0] = ceil(fmax(0.5*(qs - qp)/log(Ws[0]/Wp[0]),
-                      0.5*(qs - qp)/log(Ws[1]/Wp[1]))/2.0);
-
-    rtn[1] = exp(log(Wp[0]) - qp/2/rtn[0]);    
-    rtn[2] = exp(log(Wp[1]) - qp/2/rtn[0]);
-
-    rtn[1] = atan(rtn[2])/M_PI;
-    rtn[2] = 0.5-atan(rtn[1])/M_PI;
-
+    throw std::invalid_argument
+                         ("bandstop filter not implemented yet");
     return rtn;
   }}
   return (vector<double>) NULL;