Added SallenKey bandpass filter calculation. It works. MFB bandpass doesnot works.

qucs-activefilter/filter.cpp

@@ -39,12 +39,16 @@ Filter::Filter(Filter::FilterFunc ffunc_, Filter::FType type_, FilterParam par)
         TW = par.TW;
         BW = fabs(Fu -Fl);
         F0 = sqrt(Fu*Fl);
-        Fc=BW;          // cutoff freq. of LPF prototype
+        if (ftype==Filter::BandPass) { // BandPass
-        float Fs1 = Fu + TW;
+            Fc=BW;          // cutoff freq. of LPF prototype
-        float Fs1lp = fabsf(Fs1 - (F0*F0)/Fs1);    // stopband freq. of LPF prototype
+            float Fs1 = Fu + TW;
-        float Fs2 = Fl - TW;
+            float Fs1lp = fabsf(Fs1 - (F0*F0)/Fs1);    // stopband freq. of LPF prototype
-        float Fs2lp = fabsf(Fs2 - (F0*F0)/Fs2);
+            float Fs2 = Fl - TW;
-        Fs = std::min(Fs1lp,Fs2lp);
+            float Fs2lp = fabsf(Fs2 - (F0*F0)/Fs2);
+            Fs = std::min(Fs1lp,Fs2lp);
+        } else if (ftype==Filter::BandStop) { // BandStop
+
+        }
         Ap = 3.0;
         As = 20.0;
         qDebug()<<Fc<<Fs;

qucs-activefilter/mfbfilter.cpp

@@ -196,6 +196,16 @@ void MFBfilter::createHighPassSchematic(QString &s)
     s += "</Wires>\n";
 }
 
+void MFBfilter::createBandPassSchematic(QString &s)
+{
+
+}
+
+void MFBfilter::createBandStopSchematic(QString &s)
+{
+
+}
+
 void MFBfilter::calcHighPass()
 {
     float R1,R2,C1,C2;
@@ -259,3 +269,72 @@ void MFBfilter::calcLowPass()
 
     this->calcFirstOrder();
 }
+
+void MFBfilter::calcBandPass()
+{
+    float W0 = 2*M_PI*F0;
+    float R1,R2,R3,C1,C2;
+    //float rho = Kv/Q;
+    //float gamma = 1.0;
+    int cnt = 1;
+
+    for (int k=1; k <= order/2; k++) {
+        float re = Poles.at(k-1).real();
+        float im = Poles.at(k-1).imag();
+        float B = -2.0*re;
+        float C = re*re + im*im;
+
+        float H = C + 4.0*Q*Q;
+        float E = (1.0/B)*sqrt(0.5*(H+sqrt(H*H-(4.0*B*B*Q*Q))));
+        float F = (B*E)/Q;
+        float D = 0.5*(F+sqrt(F*F-4.0));
+
+        qDebug()<<D<<E<<Q;
+
+        float rho = Kv*sqrt(C)/Q;
+        float beta = D/E;
+        float gamma = D*D;
+
+        C1 = 10.0/F0;
+        C2 = C1*(rho*beta-gamma)/gamma;
+        R1 = 1.0/(rho*W0*C1);
+        R2 = beta/((C1*(gamma-rho*beta)+gamma*C2)*W0);
+        R3 = (1.0/C1+1.0/C2)/(beta*W0);
+
+        RC_elements current_section;
+        current_section.N = cnt;
+        current_section.R1 = R1;
+        current_section.R2 = R2;
+        current_section.R3 = R3;
+        current_section.C1 = C1;
+        current_section.C2 = C2;
+        Sections.append(current_section);
+
+        cnt++;
+
+        beta = 1.0/(D*E);
+        gamma = 1.0/(D*D);
+        C1 = 10.0/F0;
+        C2 = C1*(rho*beta-gamma)/gamma;
+        R1 = 1.0/(rho*W0*C1);
+        R2 = beta/((C1*(gamma-rho*beta)+gamma*C2)*W0);
+        R3 = (1.0/C1+1.0/C2)/(beta*W0);
+
+        current_section.N = cnt;
+        current_section.R1 = R1;
+        current_section.R2 = R2;
+        current_section.R3 = R3;
+        current_section.C1 = C1;
+        current_section.C2 = C2;
+        Sections.append(current_section);
+
+        cnt++;
+
+
+    }
+}
+
+void MFBfilter::calcBandStop()
+{
+
+}

qucs-activefilter/mfbfilter.h

@@ -27,8 +27,12 @@ class MFBfilter : public Filter
 protected:
     void calcHighPass();
     void calcLowPass();
+    void calcBandPass();
+    void calcBandStop();
     void createHighPassSchematic(QString &s);
     void createLowPassSchematic(QString &s);
+    void createBandPassSchematic(QString &s);
+    void createBandStopSchematic(QString &s);
 
 public:
     MFBfilter(Filter::FilterFunc ffunc_, Filter::FType type_, FilterParam par);

qucs-activefilter/sallenkey.cpp

@@ -117,6 +117,78 @@ void SallenKey::calcHighPass()
     calcFirstOrder();
 }
 
+
+void SallenKey::calcBandPass()
+{
+    float W0 = 2*M_PI*F0;
+    float R1,R2,R3,R4,C1;
+    //float rho = Kv/Q;
+    //float gamma = 1.0;
+    int cnt = 1;
+
+    for (int k=1; k <= order/2; k++) {
+        float re = Poles.at(k-1).real();
+        float im = Poles.at(k-1).imag();
+        float B = -2.0*re;
+        float C = re*re + im*im;
+
+        float H = C + 4.0*Q*Q;
+        float E = (1.0/B)*sqrt(0.5*(H+sqrt(H*H-(4.0*B*B*Q*Q))));
+        float F = (B*E)/Q;
+        float D = 0.5*(F+sqrt(F*F-4.0));
+
+        qDebug()<<D<<E<<Q;
+
+        float rho = Kv*sqrt(C)/Q;
+        float beta = D/E;
+        float gamma = D*D;
+
+        C1 = 10.0/F0;
+        R1 = 2.0/(rho*W0*C1);
+        R2 = 2.0/((-beta+sqrt((rho-beta)*(rho-beta)+8.0*gamma))*W0*C1);
+        R3 = (1.0/R1+1.0/R2)/(gamma*W0*W0*C1*C1);
+        R4 = 2.0*R3;
+
+        RC_elements current_section;
+        current_section.N = cnt;
+        current_section.R1 = 1000*R1;
+        current_section.R2 = 1000*R2;
+        current_section.R3 = 1000*R3;
+        current_section.R4 = 1000*R4;
+        current_section.C1 = C1;
+        current_section.C2 = C1;
+        Sections.append(current_section);
+
+        cnt++;
+
+        beta = 1.0/(D*E);
+        gamma = 1.0/(D*D);
+        C1 = 10.0/F0;
+        R1 = 2.0/(rho*W0*C1);
+        R2 = 2.0/((-beta+sqrt((rho-beta)*(rho-beta)+8.0*gamma))*W0*C1);
+        R3 = (1.0/R1+1.0/R2)/(gamma*W0*W0*C1*C1);
+        R4 = 2.0*R3;
+
+        current_section.N = cnt;
+        current_section.R1 = 1000*R1;
+        current_section.R2 = 1000*R2;
+        current_section.R3 = 1000*R3;
+        current_section.R4 = 1000*R4;
+        current_section.C1 = C1;
+        current_section.C2 = C1;
+        Sections.append(current_section);
+
+        cnt++;
+
+
+    }
+}
+
+void SallenKey::calcBandStop()
+{
+
+}
+
 void SallenKey::createHighPassSchematic(QString &s)
 {
     int const N_R=4; // number of resisitors in 2-order Sallen-Key stage
@@ -279,3 +351,15 @@ void SallenKey::createLowPassSchematic(QString &s)
 
     s += "</Wires>\n";
 }
+
+void SallenKey::createBandPassSchematic(QString &s)
+{
+
+}
+
+void SallenKey::createBandStopSchematic(QString &s)
+{
+
+}
+
+

qucs-activefilter/sallenkey.h

@@ -31,8 +31,12 @@ protected:
 
     void calcHighPass();
     void calcLowPass();
+    void calcBandPass();
+    void calcBandStop();
     void createHighPassSchematic(QString &s);
     void createLowPassSchematic(QString &s);
+    void createBandPassSchematic(QString &s);
+    void createBandStopSchematic(QString &s);
 
 public:
     SallenKey(Filter::FilterFunc ffunc_, Filter::FType type_, FilterParam par);