writing coef notch


    Nov 11 2011 | 4:23 am
    Dear all I try to write coeff notch object any comment is welcome so the idea is this :
    //notch: H(s) = (s^2 + 1) / (s^2 + s/Q + 1);
    // omega = 2*PI*CutOff_Frequency/Sampling_Frequency;
    //sn = sin(omega);
    //cs = cos(omega);
    //alpha = sn/(2*Q);
    //a0 = 1;
    //a1 = -2*cs;
    //a2 = 1;
    //b0 = 1 + alpha;
    //b1 = -2*cs;
    //b2 = 1 - alpha;
    //Q= CutOff_Frequency/BW_Coeff
    void _coef_notch_Test(short int *Data_In,
    short int *Data_Out,
    long nData_Length,
    double Sampling_Frequency,
    double CutOff_Frequency,
    double BW_Coeff)
    {
    {
    // If wrong parameters:
    if((NULL == Data_In)||(Data_Out)||(nData_Length if((Sampling_Frequency < 0.0)||(CutOff_Frequency < 0.0)) return;
    if(CutOff_Frequency > (Sampling_Frequency/2)) return;
    if((BW_Coeff = 1.0)) return;
    //constantes:
    static const double PI = 3.141592654;
    static const double Sampling_Frequency = 22050;
    //filter coefficients :
    double a0 = 1;
    double a1 = -2 * cos(2*PI*CutOff_Frequency/Sampling_Frequency);
    double a2 = 1;
    double b0 = 1 + sin(2*PI*CutOff_Frequency/Sampling_Frequency)/(2*(CutOff_Frequency/BW_Coeff));
    double b1 = -2 * cos(2*PI*CutOff_Frequency/Sampling_Frequency);
    double b2 = 1 - sin(2*PI*CutOff_Frequency/Sampling_Frequency)/(2*(CutOff_Frequency/BW_Coeff));
    I try write an equivalent of maxmsp patcher.

    • Nov 22 2011 | 10:06 am
      ehm, so what is the question exactly? did you try to implement this?
    • Nov 24 2011 | 11:52 pm
      Yes Timo, I try to implement this/