FFTWindow Class Reference

#include <fftwindow.h>

Public Types
enum	Function {   Bartlett, BlackmanHarris, Flattop, Hamming,   Hanning, Rectangle }

Public Member Functions
void	create (Function function, int n)
void	apply (const std::vector< Real > &in, std::vector< Real > *out)
void	apply (const std::vector< Complex > &in, std::vector< Complex > *out)
void	apply (const Complex *in, Complex *out)

Static Private Member Functions
static Real	flatTop (Real n, Real i)
static Real	bartlett (Real n, Real i)
static Real	blackmanHarris (Real n, Real i)
static Real	hamming (Real n, Real i)
static Real	hanning (Real n, Real i)
static Real	rectangle (Real, Real)

Private Attributes
std::vector< float >	m_window

Detailed Description

Definition at line 31 of file fftwindow.h.

Member Enumeration Documentation

Function

enum FFTWindow::Function

Enumerator
Bartlett
BlackmanHarris
Flattop
Hamming
Hanning
Rectangle

Definition at line 33 of file fftwindow.h.

                  {
        Bartlett,
        BlackmanHarris,
        Flattop,
        Hamming,
        Hanning,
        Rectangle
    };

Member Function Documentation

apply() [1/3]

void FFTWindow::apply	(	const std::vector< Real > &	in,
		std::vector< Real > *	out
	)

Definition at line 58 of file fftwindow.cpp.

References i, and m_window.

Referenced by SpectrumVis::feed().

{
    for(size_t i = 0; i < m_window.size(); i++)
        (*out)[i] = in[i] * m_window[i];
}

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apply() [2/3]

void FFTWindow::apply	(	const std::vector< Complex > &	in,
		std::vector< Complex > *	out
	)

Definition at line 64 of file fftwindow.cpp.

References i, and m_window.

{
    for(size_t i = 0; i < m_window.size(); i++)
        (*out)[i] = in[i] * m_window[i];
}

apply() [3/3]

void FFTWindow::apply	(	const Complex *	in,
		Complex *	out
	)

Definition at line 70 of file fftwindow.cpp.

References i, and m_window.

{
    for(size_t i = 0; i < m_window.size(); i++)
        out[i] = in[i] * m_window[i];
}

bartlett()

static Real FFTWindow::bartlett ( Real  n, Real  i  )

inlinestaticprivate

Definition at line 56 of file fftwindow.h.

Referenced by create().

    {
        // amplitude correction = 2.0
        return (2.0 / (n - 1.0)) * ( (n - 1.0) / 2.0 - fabs(i - (n - 1.0) / 2.0)) * 2.0;
    }

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blackmanHarris()

static Real FFTWindow::blackmanHarris ( Real  n, Real  i  )

inlinestaticprivate

Definition at line 62 of file fftwindow.h.

References cos(), and M_PI.

Referenced by create().

    {
        // amplitude correction = 2.79
        return (0.35875 - 0.48829 * cos((2.0 * M_PI * i) / n) + 0.14128 * cos((4.0 * M_PI * i) / n) - 0.01168 * cos((6.0 * M_PI * i) / n)) * 2.79;
    }

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create()

void FFTWindow::create	(	Function	function,
		int	n
	)

Definition at line 21 of file fftwindow.cpp.

References Bartlett, bartlett(), BlackmanHarris, blackmanHarris(), Flattop, flatTop(), Hamming, hamming(), Hanning, hanning(), i, m_window, Rectangle, and rectangle().

Referenced by SpectrumVis::handleConfigure().

{
    Real (*wFunc)(Real n, Real i);

    m_window.clear();

    switch(function) {
        case Flattop:
            wFunc = flatTop;
            break;

        case Bartlett:
            wFunc = bartlett;
            break;

        case BlackmanHarris:
            wFunc = blackmanHarris;
            break;

        case Hamming:
            wFunc = hamming;
            break;

        case Hanning:
            wFunc = hanning;
            break;

        case Rectangle:
        default:
            wFunc = rectangle;
            break;
    }

    for(int i = 0; i < n; i++)
        m_window.push_back(wFunc(n, i));
}

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flatTop()

static Real FFTWindow::flatTop ( Real  n, Real  i  )

inlinestaticprivate

Definition at line 50 of file fftwindow.h.

References cos(), and M_PI.

Referenced by create().

    {
        // correction ?
        return 1.0 - 1.93 * cos((2.0 * M_PI * i) / n) + 1.29 * cos((4.0 * M_PI * i) / n) - 0.388 * cos((6.0 * M_PI * i) / n) + 0.03222 * cos((8.0 * M_PI * i) / n);
    }

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hamming()

static Real FFTWindow::hamming ( Real  n, Real  i  )

inlinestaticprivate

Definition at line 68 of file fftwindow.h.

References cos(), and M_PI.

Referenced by create().

    {
        // amplitude correction = 1.855, energy correction = 1.586
        return (0.54 - 0.46 * cos((2.0 * M_PI * i) / n)) * 1.855;
    }

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hanning()

static Real FFTWindow::hanning ( Real  n, Real  i  )

inlinestaticprivate

Definition at line 74 of file fftwindow.h.

References cos(), and M_PI.

Referenced by create().

    {
        // amplitude correction = 2.0, energy correction = 1.633
        return (0.5 - 0.5 * cos((2.0 * M_PI * i) / n)) * 2.0;
    }

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rectangle()

static Real FFTWindow::rectangle ( Real  , Real    )

inlinestaticprivate

Definition at line 80 of file fftwindow.h.

Referenced by create().

    {
        return 1.0;
    }

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Member Data Documentation

m_window

std::vector<float> FFTWindow::m_window

private

Definition at line 48 of file fftwindow.h.

Referenced by apply(), and create().

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The documentation for this class was generated from the following files:

• sdrbase/dsp/fftwindow.h
• sdrbase/dsp/fftwindow.cpp