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iir_31.h
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iir_31.h
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// DD4WH LPF DC - 3.1 kHz
// (sampling rate 44.117 kHz)
// 12.2.2016
// Parameters generated using Iowa Hills IIR Filter Designer
// 8th order Inv Cheby Lowpass (4-stage cascaded biquad)
//
//
//
// The array of coefficients is in order: B0, B1, B2, A1, A2. Each coefficient must be less than 2.0 and greater than -2.0. The array should be type double.
// unlike output by Iowa Hils IIR Filter Designer !
const double IIR_31_Coeffs_0[] =
{
0.516676615096921532,
-0.819792954551865849,
0.516676615096921532,
-1.094656125530478310,
0.308216401172455579,
};
const double IIR_31_Coeffs_1[] =
{
0.358508197603467582,
-0.518847077512281984,
0.358508197603467582,
-1.257630547496234370,
0.455799865190887388
};
const double IIR_31_Coeffs_2[] =
{
0.173478188104338238,
-0.163591138608289915,
0.173478188104338238,
-1.480176015318265480,
0.663541252918652180
};
const double IIR_31_Coeffs_3[] =
{
0.061411582893547395,
0.060040463689562951,
0.061411582893547395,
-1.699310973939165190,
0.882174603415822989
};
/*
// ELLIPTIC filter coefficients
// works, but with an unpleasant and annoying hiss sound!
const double IIR_31_Coeffs_0[] =
{
0.211735067967220886,
-0.365798354728391173,
0.211735067967220886,
-1.568543543770871020,
0.626215324976921672
};
const double IIR_31_Coeffs_1[] =
{
0.326582053814130580,
-0.544927310238951357,
0.326582053814130580,
-1.640791514445660180,
0.749028311834969984
};
const double IIR_31_Coeffs_2[] =
{
0.274329980165261500,
-0.390258125345878171,
0.274329980165261500,
-1.718502911800378290,
0.876904746785023170
};
const double IIR_31_Coeffs_3[] =
{
0.085499318375426445,
0.014729186060807581,
0.085499318375426445,
-1.778873148815911740,
0.964600971627572412
};
*/