//public override void GetDigitalLPF(double w, Coefficient[] coefs)
public void GetDigitalLPF2(double w, Coefficient[] coefs)
{
double sin, cos;
GetSinCos(w, out sin, out cos);
double b0 = (1 - cos) / 2;
double a1 = -2 * cos;
double nu = (this.order & 1) == 1 ? 1 : 0.5;
for(int i=this.order-1, j=0; i>0; i-=2, ++j)
{
Coefficient coef = coefs[j];
double alpha = sin * Math.Cos(Math.PI / 2.0 * (double)i / this.order);
coef.a[0] = 1 + alpha;
coef.a[1] = a1;
coef.a[2] = 1 - alpha;
coef.b[0] = b0;
coef.b[1] = 2 * b0;
coef.b[2] = b0;
}
if((this.order & 1) == 1)
{
Coefficient coef = coefs[this.order / 2];
coef.a[0] = sin + cos + 1;
coef.a[1] = sin - cos - 1;
coef.a[2] = 0;
coef.b[0] = sin;
coef.b[1] = sin;
coef.b[2] = 0;
}
}
//public override void GetAnalogPrototype(Coefficient[] coefs)
public void GetAnalogPrototype2(Coefficient[] coefs)
{
for(int i=this.order-1, j=0; i>0; i-=2, ++j)
{
Coefficient coef = coefs[j];
coef.a[0] = 1;
coef.a[1] = 2 * Math.Cos(Math.PI / 2 * (double)i / this.order);
coef.a[2] = 1;
coef.b[0] = 1;
coef.b[1] = 0;
coef.b[2] = 0;
}
if((this.order & 1) == 1)
{
Coefficient coef = coefs[this.order / 2];
coef.a[0] = 1;
coef.a[1] = 1;
coef.a[2] = 0;
coef.b[0] = 1;
coef.b[1] = 0;
coef.b[2] = 0;
}
}
//public override void GetAnalogPrototype(Coefficient[] coefs)
public void GetAnalogPrototype2(Coefficient[] coefs)
{
for (int i = this.order - 1, j = 0; i > 0; i -= 2, ++j)
{
Coefficient coef = coefs[j];
coef.a[0] = 1;
coef.a[1] = 2 * Math.Cos(Math.PI / 2 * (double)i / this.order);
coef.a[2] = 1;
coef.b[0] = 1;
coef.b[1] = 0;
coef.b[2] = 0;
}
if ((this.order & 1) == 1)
{
Coefficient coef = coefs[this.order / 2];
coef.a[0] = 1;
coef.a[1] = 1;
coef.a[2] = 0;
coef.b[0] = 1;
coef.b[1] = 0;
coef.b[2] = 0;
}
}
public static void ToPeqCoefficient(Coefficient digital, ParametricEqualizer.Parameter peq)
{
double[] a = digital.a;
double[] b = digital.b;
peq.c = b[0] / a[0];
peq.a1 = -a[1] / a[0];
peq.a2 = -a[2] / a[0];
peq.b1 = b[1] / b[0];
peq.b2 = b[2] / b[0];
}
/// <summary>
/// ディジタル LPF 係数を計算。
/// </summary>
/// <param name="w">カットオフ周波数</param>
/// <returns>ディジタル LPF 係数</returns>
public Coefficient[] GetDigitalLPF(double w)
{
Coefficient[] coefs = new Coefficient[this.Length];
for (int i = 0; i < coefs.Length; ++i)
{
coefs[i] = new Coefficient();
}
this.GetDigitalLPF(w, coefs);
return(coefs);
}
/// <summary>
/// アナログプロトタイプフィルタの係数を計算。
/// </summary>
/// <returns>AP フィルタ係数</returns>
public Coefficient[] GetAnalogPrototype()
{
Coefficient[] coefs = new Coefficient[this.Length];
for (int i = 0; i < coefs.Length; ++i)
{
coefs[i] = new Coefficient();
}
this.GetAnalogPrototype(coefs);
return(coefs);
}
public override void GetAnalogPrototype(Coefficient[] coefs)
// public void GetAnalogPrototype2(Coefficient[] coefs)
{
double m1 = this.m1;
double m1p = 1 - this.m1;
double Kk1 = Elliptic.K(m1);
double Kk1p = Elliptic.K(m1p);
double m = Elliptic.InverseQ(Math.Exp(-Math.PI * Kk1p / (this.order * Kk1)));
double mp = 1 - m;
double Kk = Elliptic.K(m);
double phi, sn_p, cn_p, dn_p;
double v = Elliptic.F(Math.Atan(1 / this.epsilon), m1p) * Kk / (this.order * Kk1);
Elliptic.Jacobi(v, mp, out phi, out sn_p, out cn_p, out dn_p);
for (int i = this.order - 1, j = 0; i > 0; i -= 2, ++j)
{
Coefficient coef = coefs[j];
double sn, cn, dn;
double u = Kk * (double)i / this.order;
Elliptic.Jacobi(u, m, out phi, out sn, out cn, out dn);
double denom = 1 - dn * dn * sn_p * sn_p;
double re = -cn * dn * sn_p * cn_p / denom;
double im = -sn * dn_p / denom;
double alpha = -2 * re;
double beta = re * re + im * im;
double gamma = 1 / (m * sn * sn);
coef.a[0] = 1; coef.a[1] = alpha / beta; coef.a[2] = 1 / beta;
coef.b[0] = 1; coef.b[1] = 0; coef.b[2] = 1 / gamma;
}
if ((this.order & 1) == 1)
{
Coefficient coef = coefs[this.order / 2];
double denom = 1 - sn_p * sn_p;
double re = -sn_p * cn_p / denom;
coef.a[0] = 1; coef.a[1] = -1 / re; coef.a[2] = 0;
coef.b[0] = 1; coef.b[1] = 0; coef.b[2] = 0;
}
}
public override void GetAnalogPrototype(Coefficient[] coefs)
{
double beta0 = this.Beta0;
for (int i = this.order - 1, j = 0; i > 0; i -= 2, ++j)
{
Coefficient coef = coefs[j];
double sin, cos;
GetSinCos(Math.PI / 2 * (double)i / this.order, out sin, out cos);
double alpha = 2 * beta0 * cos;
double beta = sin;
beta *= beta;
double gamma = beta;
beta += beta0 * beta0;
if (this.kind)
{
coef.a[0] = 1; coef.a[1] = alpha; coef.a[2] = beta;
coef.b[0] = 1; coef.b[1] = 0; coef.b[2] = gamma;
}
else
{
coef.a[0] = beta; coef.a[1] = alpha; coef.a[2] = 1;
coef.b[0] = beta; coef.b[1] = 0; coef.b[2] = 0;
}
}
if ((this.order & 1) == 1)
{
Coefficient coef = coefs[this.order / 2];
if (this.kind)
{
coef.a[0] = 1; coef.a[1] = beta0; coef.a[2] = 0;
coef.b[0] = 1; coef.b[1] = 0; coef.b[2] = 0;
}
else
{
coef.a[0] = beta0; coef.a[1] = 1; coef.a[2] = 0;
coef.b[0] = beta0; coef.b[1] = 0; coef.b[2] = 0;
}
}
}
public static void BilinearTransform(Coefficient ap, Coefficient digital, double sin, double cos)
{
if (ap.a[2] != 0 || ap.b[2] != 0)
{
BilinearTransform(
ap.a[0], ap.a[1], ap.a[2],
out digital.a[0], out digital.a[1], out digital.a[2],
sin, cos);
BilinearTransform(
ap.b[0], ap.b[1], ap.b[2],
out digital.b[0], out digital.b[1], out digital.b[2],
sin, cos);
return;
}
digital.a[2] = 0;
digital.b[2] = 0;
if (ap.a[1] != 0 || ap.b[1] != 0)
{
BilinearTransform(
ap.a[0], ap.a[1],
out digital.a[0], out digital.a[1],
sin, cos);
BilinearTransform(
ap.b[0], ap.b[1],
out digital.b[0], out digital.b[1],
sin, cos);
return;
}
digital.a[1] = 0;
digital.b[1] = 0;
digital.a[0] = ap.a[0];
digital.b[0] = ap.b[0];
}
//public override void GetDigitalLPF(double w, Coefficient[] coefs)
public void GetDigitalLPF2(double w, Coefficient[] coefs)
{
double sin, cos;
GetSinCos(w, out sin, out cos);
double b0 = (1 - cos) / 2;
double a1 = -2 * cos;
double nu = (this.order & 1) == 1 ? 1 : 0.5;
for (int i = this.order - 1, j = 0; i > 0; i -= 2, ++j)
{
Coefficient coef = coefs[j];
double alpha = sin * Math.Cos(Math.PI / 2.0 * (double)i / this.order);
coef.a[0] = 1 + alpha;
coef.a[1] = a1;
coef.a[2] = 1 - alpha;
coef.b[0] = b0;
coef.b[1] = 2 * b0;
coef.b[2] = b0;
}
if ((this.order & 1) == 1)
{
Coefficient coef = coefs[this.order / 2];
coef.a[0] = sin + cos + 1;
coef.a[1] = sin - cos - 1;
coef.a[2] = 0;
coef.b[0] = sin;
coef.b[1] = sin;
coef.b[2] = 0;
}
}
public override void GetAnalogPrototype(Coefficient[] coefs)
// public void GetAnalogPrototype2(Coefficient[] coefs)
{
double m1 = this.m1;
double m1p = 1 - this.m1;
double Kk1 = Elliptic.K(m1);
double Kk1p = Elliptic.K(m1p);
double m = Elliptic.InverseQ(Math.Exp(-Math.PI * Kk1p / (this.order * Kk1)));
double mp = 1 - m;
double Kk = Elliptic.K(m);
double phi, sn_p, cn_p, dn_p;
double v = Elliptic.F(Math.Atan(1 / this.epsilon), m1p) * Kk / (this.order * Kk1);
Elliptic.Jacobi(v, mp, out phi, out sn_p, out cn_p, out dn_p);
for(int i=this.order-1, j=0; i>0; i-=2, ++j)
{
Coefficient coef = coefs[j];
double sn, cn, dn;
double u = Kk * (double)i / this.order;
Elliptic.Jacobi(u, m, out phi, out sn, out cn, out dn);
double denom = 1 - dn * dn * sn_p * sn_p;
double re = -cn * dn * sn_p * cn_p / denom;
double im = -sn * dn_p / denom;
double alpha = -2 * re;
double beta = re * re + im * im;
double gamma = 1 / (m * sn * sn);
coef.a[0] = 1; coef.a[1] = alpha / beta; coef.a[2] = 1 / beta;
coef.b[0] = 1; coef.b[1] = 0; coef.b[2] = 1 / gamma;
}
if((this.order & 1) == 1)
{
Coefficient coef = coefs[this.order / 2];
double denom = 1 - sn_p * sn_p;
double re = -sn_p * cn_p / denom;
coef.a[0] = 1; coef.a[1] = -1 / re; coef.a[2] = 0;
coef.b[0] = 1; coef.b[1] = 0; coef.b[2] = 0;
}
}
/// <summary>
/// ディジタル LPF 係数を計算。
/// </summary>
/// <param name="w">カットオフ周波数</param>
/// <returns>ディジタル LPF 係数</returns>
public Coefficient[] GetDigitalLPF(double w)
{
Coefficient[] coefs = new Coefficient[this.Length];
for(int i=0; i<coefs.Length; ++i) coefs[i] = new Coefficient();
this.GetDigitalLPF(w, coefs);
return coefs;
}
/// <summary>
/// ディジタル LPF 係数を計算。
/// </summary>
/// <param name="w">カットオフ周波数</param>
/// <param name="coefs">計算結果の格納先</param>
public virtual void GetDigitalLPF(double w, Coefficient[] coefs)
{
this.GetAnalogPrototype(coefs);
BilinearTransform(coefs, coefs, w);
}
public static void ZeroPoleToAnalogPrototype(ZeroPole zeropole, Coefficient coef)
{
RootToAnalogPrototype(zeropole.zero, coef.b);
RootToAnalogPrototype(zeropole.pole, coef.a);
}
public static void ZeroPoleToAnalogPrototype(ZeroPole zeropole, Coefficient coef)
{
RootToAnalogPrototype(zeropole.zero, coef.b);
RootToAnalogPrototype(zeropole.pole, coef.a);
}
public override void GetAnalogPrototype(Coefficient[] coefs)
{
double beta0 = this.Beta0;
for(int i=this.order-1, j=0; i>0; i-=2, ++j)
{
Coefficient coef = coefs[j];
double sin, cos;
GetSinCos(Math.PI / 2 * (double)i / this.order, out sin, out cos);
double alpha = 2 * beta0 * cos;
double beta = sin;
beta *= beta;
double gamma = beta;
beta += beta0 * beta0;
if(this.kind)
{
coef.a[0] = 1; coef.a[1] = alpha; coef.a[2] = beta;
coef.b[0] = 1; coef.b[1] = 0; coef.b[2] = gamma;
}
else
{
coef.a[0] = beta; coef.a[1] = alpha; coef.a[2] = 1;
coef.b[0] = beta; coef.b[1] = 0; coef.b[2] = 0;
}
}
if((this.order & 1) == 1)
{
Coefficient coef = coefs[this.order / 2];
if(this.kind)
{
coef.a[0] = 1; coef.a[1] = beta0; coef.a[2] = 0;
coef.b[0] = 1; coef.b[1] = 0; coef.b[2] = 0;
}
else
{
coef.a[0] = beta0; coef.a[1] = 1; coef.a[2] = 0;
coef.b[0] = beta0; coef.b[1] = 0; coef.b[2] = 0;
}
}
}
public static void ZeroPoleToAnalogPrototype(ZeroPole[] roots, Coefficient[] coefs)
{
for(int i=0; i<roots.Length; ++i)
{
ZeroPoleToAnalogPrototype(roots[i], coefs[i]);
}
}
public static void BilinearTransform(Coefficient ap, Coefficient digital, double sin, double cos)
{
if(ap.a[2] != 0 || ap.b[2] != 0)
{
BilinearTransform(
ap.a[0], ap.a[1], ap.a[2],
out digital.a[0], out digital.a[1], out digital.a[2],
sin, cos);
BilinearTransform(
ap.b[0], ap.b[1], ap.b[2],
out digital.b[0], out digital.b[1], out digital.b[2],
sin, cos);
return;
}
digital.a[2] = 0;
digital.b[2] = 0;
if(ap.a[1] != 0 || ap.b[1] != 0)
{
BilinearTransform(
ap.a[0], ap.a[1],
out digital.a[0], out digital.a[1],
sin, cos);
BilinearTransform(
ap.b[0], ap.b[1],
out digital.b[0], out digital.b[1],
sin, cos);
return;
}
digital.a[1] = 0;
digital.b[1] = 0;
digital.a[0] = ap.a[0];
digital.b[0] = ap.b[0];
}
public static void BilinearTransform(Coefficient[] ap, Coefficient[] digital, double w)
{
double sin, cos;
GetSinCos(w, out sin, out cos);
for(int i=0; i<ap.Length; ++i)
{
BilinearTransform(ap[i], digital[i], sin, cos);
}
}
/// <summary>
/// アナログプロトタイプフィルタの係数を計算。
/// </summary>
/// <param name="coefs">計算結果の格納先</param>
public virtual void GetAnalogPrototype(Coefficient[] coefs)
{
ZeroPole[] roots = this.GetZeroPole();
ZeroPoleToAnalogPrototype(roots, coefs);
}
/// <summary>
/// アナログプロトタイプフィルタの係数を計算。
/// </summary>
/// <returns>AP フィルタ係数</returns>
public Coefficient[] GetAnalogPrototype()
{
Coefficient[] coefs = new Coefficient[this.Length];
for(int i=0; i<coefs.Length; ++i) coefs[i] = new Coefficient();
this.GetAnalogPrototype(coefs);
return coefs;
}
public static void ToPeqCoefficient(Coefficient[] digital, ParametricEqualizer.Parameter[] peq)
{
for(int i=0; i<digital.Length; ++i)
{
ToPeqCoefficient(digital[i], peq[i]);
}
}
public static void ToPeqCoefficient(Coefficient digital, ParametricEqualizer.Parameter peq)
{
double[] a = digital.a;
double[] b = digital.b;
peq.c = b[0] / a[0];
peq.a1 = -a[1] / a[0];
peq.a2 = -a[2] / a[0];
peq.b1 = b[1] / b[0];
peq.b2 = b[2] / b[0];
}