Loris::KaiserWindow Class Reference

#include <KaiserWindow.h>

List of all members.

Static Public Member Functions
static void	buildWindow (std::vector< double > &win, double shape)
static void	buildTimeDerivativeWindow (std::vector< double > &win, double shape)
static double	computeShape (double atten)
static unsigned long	computeLength (double width, double alpha)

---

Detailed Description

Computes samples of a Kaiser window function (see Kaiser and Schafer, 1980) for windowing FFT data.

---

Member Function Documentation

static void Loris::KaiserWindow::buildTimeDerivativeWindow	(	std::vector< double > &	win,
		double	shape
	)			[static]

Build a new time-derivative Kaiser analysis window having the specified shaping parameter, for computing frequency reassignment. The closed form for the time derivative can be obtained from the property of modified Bessel functions that the derivative of the zeroeth order function is equal to the first order function.

Parameters:

	win	is the vector that will store the window samples. The number of samples computed will be equal to the length of this vector. Any previous contents will be overwritten.
	shape	is the Kaiser shaping parameter, controlling the sidelobe rejection level.

static void Loris::KaiserWindow::buildWindow	(	std::vector< double > &	win,
		double	shape
	)			[static]

Build a new Kaiser analysis window having the specified shaping parameter. See Oppenheim and Schafer: "Digital Signal Processing" (1975), p. 452 for further explanation of the Kaiser window. Also, see Kaiser and Schafer, 1980.

Parameters:

	win	is the vector that will store the window samples. The number of samples computed will be equal to the length of this vector. Any previous contents will be overwritten.
	shape	is the Kaiser shaping parameter, controlling the sidelobe rejection level.

static unsigned long Loris::KaiserWindow::computeLength	(	double	width,
		double	alpha
	)			[static]

Compute the necessary length in samples of a Kaiser window having the specified shaping parameter that has the desired main lobe width.

Parameters:

	width	is the desired main lobe width expressed as a fraction of the sample rate.
	alpha	is the Kaiser shaping parameter (the main lobe width is influenced primarily by the window length,but also by the shape).

Returns:

the window length in samples

static double Loris::KaiserWindow::computeShape

(

double

atten

)

[static]

Compute a shaping parameter that will achieve the specified level of sidelobe rejection.

Parameters:

atten

is the desired sidelobe attenuation in positive decibels (e.g. 65 dB)

Returns:

the Kaiser shaping paramater

---

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

• /Users/kfitz/Projects/Loris/Loris development/src/KaiserWindow.h