Filterdesign mit WinFilter


http://www.winfilter.20m.com

This software can design as well IIR filters as FIR filters and can generate the C and VHDLKeine Zugangsberechtigung code.

Generierung von VHDLKeine Zugangsberechtigung-Code für IIR-Filter nicht implementiert.

Beispiel: FIR-Filter


image

Generierter C-Code:
fir.c
/**************************************************************
WinFilter version 0.8
http://www.winfilter.20m.com
akundert@hotmail.com

Filter type: Low Pass
Filter model: Raised Cosine
Roll Off Factor: 0.500000
Sampling Frequency: 1000 Hz
Cut Frequency: 100.000000 Hz
Coefficents Quantization: 16-bit
***************************************************************/

#define Ntap 31

#define DCgain 131072

__int16 fir(__int16 NewSample) {
    __int16 FIRCoef[Ntap] = {
            0,
           69,
          302,
          573,
          602,
           85,
        -1068,
        -2531,
        -3521,
        -3019,
         -201,
         5093,
        12099,
        19226,
        24557,
        26533,
        24557,
        19226,
        12099,
         5093,
         -201,
        -3019,
        -3521,
        -2531,
        -1068,
           85,
          602,
          573,
          302,
           69,
            0
    };

    static __int16 x[Ntap]; //input samples
    __int32 y=0;            //output sample
    int n;

    //shift the old samples
    for(n=Ntap-1; n>0; n--)
       x[n] = x[n-1];

    //Calculate the new output
    x[0] = NewSample;
    for(n=0; n<Ntap; n++)
        y += FIRCoef[n] * x[n];
   
    return y / DCgain;
}





Beispiel: IIR-Filter


image

Generierter C-Code:
iir.c
/**************************************************************
WinFilter version 0.8
http://www.winfilter.20m.com
akundert@hotmail.com

Filter type: Low Pass
Filter model: Chebyshev
Filter order: 8
Sampling Frequency: 1000 Hz
Cut Frequency: 100.000000 Hz
Pass band Ripple: 1.000000 dB
Coefficents Quantization: float

Z domain Zeros
z = -1.000000 + j 0.000000
z = -1.000000 + j 0.000000
z = -1.000000 + j 0.000000
z = -1.000000 + j 0.000000
z = -1.000000 + j 0.000000
z = -1.000000 + j 0.000000
z = -1.000000 + j 0.000000
z = -1.000000 + j 0.000000

Z domain Poles
z = 0.850893 + j -0.323757
z = 0.850893 + j 0.323757
z = 0.884821 + j -0.114819
z = 0.884821 + j 0.114819
z = 0.809355 + j -0.481042
z = 0.809355 + j 0.481042
z = 0.793689 + j -0.574205
z = 0.793689 + j 0.574205
***************************************************************/

#define NCoef 8
float iir(float NewSample) {
    float ACoef[NCoef+1] = {
        0.00000125614733130704,
        0.00001004917865045632,
        0.00003517212527659711,
        0.00007034425055319422,
        0.00008793031319149277,
        0.00007034425055319422,
        0.00003517212527659711,
        0.00001004917865045632,
        0.00000125614733130704
    };

    float BCoef[NCoef+1] = {
        1.00000000000000000000,
        -6.67751678724365230000,
        20.18180456038727400000,
        -35.97553530381035400000,
        41.30682183420727700000,
        -31.25387137874673700000,
        15.21102606778128300000,
        -4.35370698763383320000,
        0.56131294913559848000
    };

    static float y[NCoef+1]; //output samples
    static float x[NCoef+1]; //input samples
    int n;

    //shift the old samples
    for(n=NCoef; n>0; n--) {
       x[n] = x[n-1];
       y[n] = y[n-1];
    }

    //Calculate the new output
    x[0] = NewSample;
    y[0] = ACoef[0] * x[0];
    for(n=1; n<=NCoef; n++)
        y[0] += ACoef[n] * x[n] - BCoef[n] * y[n];
   
    return y[0];
}






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