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added triangle window

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This commit is contained in:
Robert 2021-04-29 17:14:29 +02:00
parent fbc2851533
commit c903658f65
3 changed files with 37 additions and 23 deletions
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40
src/FFT.cpp
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@ -12,28 +12,30 @@ using namespace std::complex_literals;
typedef std::function<double(unsigned int)> WindowFunction;
static WindowFunction window;
inline double WindowRectangle(unsigned int k, unsigned int offset, unsigned int width);
inline double WindowVonHann(unsigned int k, unsigned int offset, unsigned int width);
inline double WindowGauss(unsigned int k, unsigned int offset, unsigned int width);
inline double WindowTriangle(unsigned int k, unsigned int offset, unsigned int width);
std::vector<std::complex<double>>
radix2dit(
const std::vector<double>& list,
size_t offset,
size_t N,
size_t s,
WindowFunction winFunc)
size_t s)
{
std::vector<std::complex<double>> output(N);
if (N == 1)
{
output[0] = winFunc(offset) * (list[offset]);
output[0] = window(offset) * (list[offset]);
}
else
{
size_t halfN = N >> 1;
std::vector<std::complex<double>> first = radix2dit(list, offset, halfN, s << 1, winFunc);
std::vector<std::complex<double>> second = radix2dit(list, offset + s, halfN, s << 1, winFunc);
std::vector<std::complex<double>> first = radix2dit(list, offset, halfN, s << 1);
std::vector<std::complex<double>> second = radix2dit(list, offset + s, halfN, s << 1);
std::complex<double> coeff = -M_PI * 1.0i / (double)halfN;
@ -55,8 +57,7 @@ FFT(const std::vector<double>::const_iterator& begin,
const std::vector<double>::const_iterator& end,
size_t sampleRate,
double minFreq, double maxFreq,
unsigned int zeropadding,
WindowFunctions func, unsigned int width, unsigned int offset)
unsigned int zeropadding)
{
std::vector<double> signal(begin, end);
size_t N = signal.size();
@ -73,15 +74,10 @@ FFT(const std::vector<double>::const_iterator& begin,
}
WindowFunction f;
switch (func)
{
case WindowFunctions::RECTANGLE: f = std::bind(WindowRectangle, std::placeholders::_1, offset, width); break;
case WindowFunctions::VON_HANN: f = std::bind(WindowVonHann, std::placeholders::_1, offset, width); break;
case WindowFunctions::GAUSS: f = std::bind(WindowGauss, std::placeholders::_1, offset, width); break;
}
std::vector<std::complex<double>> spectrum = radix2dit(signal, 0, N, 1, f);
std::vector<std::complex<double>> spectrum = radix2dit(signal, 0, N, 1);
double freqRes = (double)sampleRate / (double)N;
double nyquistLimit = (double)sampleRate / 2.0f;
@ -99,6 +95,17 @@ FFT(const std::vector<double>::const_iterator& begin,
return output;
}
void SetWindowFunction(WindowFunctions func, unsigned int width)
{
switch (func)
{
case WindowFunctions::RECTANGLE: window = std::bind(WindowRectangle, std::placeholders::_1, 0, width); break;
case WindowFunctions::VON_HANN: window = std::bind(WindowVonHann, std::placeholders::_1, 0, width); break;
case WindowFunctions::GAUSS: window = std::bind(WindowGauss, std::placeholders::_1, 0, width); break;
case WindowFunctions::TRIANGLE: window = std::bind(WindowTriangle, std::placeholders::_1, 0, width); break;
}
}
inline double WindowRectangle(unsigned int k, unsigned int offset, unsigned int width)
{
return ((offset < k) && (k < width));
@ -114,3 +121,8 @@ inline double WindowGauss(unsigned int k, unsigned int offset, unsigned int widt
double coeff = (k - (width - 1) * 0.5f) / (0.4f * (width - 1) * 0.5f);
return ((offset < k) && (k < width)) ? (std::exp(-0.5f * coeff * coeff)) : 0;
}
inline double WindowTriangle(unsigned int k, unsigned int offset, unsigned int width)
{
return 1.0f - std::abs(((double)k - ((double)width / 2.0f)) / ((double)width / 2.0f));
}