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39 lines
2.0 KiB
C
39 lines
2.0 KiB
C
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//---------------------------------------------------------------------------
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#ifndef IIRFilterCodeH
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#define IIRFilterCodeH
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//---------------------------------------------------------------------------
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#include "LowPassPrototypes.h" // defines TFilterPoly and ARRAY_DIM
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#define OVERFLOW_LIMIT 1.0E20
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namespace kitiirfir
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{
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enum TIIRPassTypes {iirLPF, iirHPF, iirBPF, iirNOTCH, iirALLPASS};
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struct TIIRCoeff {double a0[ARRAY_DIM]; double a1[ARRAY_DIM]; double a2[ARRAY_DIM]; double a3[ARRAY_DIM]; double a4[ARRAY_DIM];
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double b0[ARRAY_DIM]; double b1[ARRAY_DIM]; double b2[ARRAY_DIM]; double b3[ARRAY_DIM]; double b4[ARRAY_DIM];
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int NumSections; };
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struct TIIRFilterParams { TIIRPassTypes IIRPassType; // Defined above: Low pass, High Pass, etc.
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double OmegaC; // The IIR filter's 3 dB corner freq for low pass and high pass, the center freq for band pass and notch.
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double BW; // The IIR filter's 3 dB bandwidth for band pass and notch filters.
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double dBGain; // Sets the Gain of the filter
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// These define the low pass prototype to be used
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TFilterPoly ProtoType; // Butterworth, Cheby, etc.
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int NumPoles; // Pole count
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double Ripple; // Passband Ripple for the Elliptic and Chebyshev
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double StopBanddB; // Stop Band Attenuation in dB for the Elliptic and Inverse Chebyshev
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double Gamma; // Controls the transition bandwidth on the Adjustable Gauss. -1 <= Gamma <= 1
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};
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TIIRCoeff CalcIIRFilterCoeff(TIIRFilterParams IIRFilt);
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void FilterWithIIR(TIIRCoeff IIRCoeff, double *Signal, double *FilteredSignal, int NumSigPts);
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double SectCalc(int j, int k, double x, TIIRCoeff IIRCoeff);
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void IIRFreqResponse(TIIRCoeff IIRCoeff, int NumSections, double *RealHofZ, double *ImagHofZ, int NumPts);
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} // namespace
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#endif
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