=====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 [[VHDL]] code.

Generierung von [[VHDL]]-Code für IIR-Filter nicht implementiert.

====Beispiel: FIR-Filter====

{{image url="images/WinFilter_fir.png"}}

Generierter C-Code:
%%(c;;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 url="images/WinFilter_iir.png"}}

Generierter C-Code:
%%(c;;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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