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use UnitCircle where possible in window functions

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Ahmet Inan 2019-01-19 09:58:31 +01:00
commit c81732c768
1 changed files with 10 additions and 4 deletions
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14
window.hh
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@ -10,6 +10,7 @@ Copyright 2018 Ahmet Inan <inan@aicodix.de>
#include "const.hh"
#include "kahan.hh"
#include "utils.hh"
#include "unit_circle.hh"
#include "coeffs.hh"
namespace DSP {
@ -25,7 +26,7 @@ struct Hann : public CoeffsFunc<TYPE>
{
TYPE operator () (int n, int N)
{
return TYPE(0.5) * (TYPE(1) - std::cos(Const<TYPE>::TwoPi() * TYPE(n) / TYPE(N - 1)));
return TYPE(0.5) * (TYPE(1) - UnitCircle<TYPE>::cos(n, N - 1));
}
};
@ -34,16 +35,21 @@ struct Hamming : public CoeffsFunc<TYPE>
{
TYPE operator () (int n, int N)
{
return TYPE(0.54) - TYPE(0.46) * std::cos(Const<TYPE>::TwoPi() * TYPE(n) / TYPE(N - 1));
return TYPE(0.54) - TYPE(0.46) * UnitCircle<TYPE>::cos(n, N - 1);
}
};
template <typename TYPE>
class Lanczos : public CoeffsFunc<TYPE>
struct Lanczos : public CoeffsFunc<TYPE>
{
TYPE operator () (int n, int N)
{
#if 0
return sinc(TYPE(2 * n) / TYPE(N - 1) - TYPE(1));
#else
return 2*n == N-1 ? TYPE(1) :
UnitCircle<TYPE>::sin(2*n-(N-1), 2*(N-1)) / (Const<TYPE>::Pi()*TYPE(2*n-(N-1))/TYPE(N-1));
#endif
}
};
@ -58,7 +64,7 @@ public:
Blackman() : Blackman(TYPE(7938) / TYPE(18608), TYPE(9240) / TYPE(18608), TYPE(1430) / TYPE(18608)) {}
TYPE operator () (int n, int N)
{
return a0 - a1 * std::cos(Const<TYPE>::TwoPi() * TYPE(n) / TYPE(N - 1)) + a2 * std::cos(Const<TYPE>::FourPi() * TYPE(n) / TYPE(N - 1));
return a0 - a1 * UnitCircle<TYPE>::cos(n, N-1) + a2 * UnitCircle<TYPE>::cos((2*n)%(N-1), N-1);
}
};