Macros
#define	SDT_ver 078
	SDT version number.

#define	SDT_ver_str "078"
	SDT version string.

#define	SDT_PI 3.141592653589793
	Value of Pi.

#define	SDT_TWOPI 6.283185307179586
	Value of 2 * Pi.

#define	SDT_EULER 2.718281828459045
	Euler number.

#define	SDT_SQRT2 1.4142135623730951
	Square root of 2.

#define	SDT_MACH1 340.29
	Mach 1, speed of sound in air under normal atmospheric conditions (m/s)

#define	SDT_EARTH 9.81
	Earth gravity (N/Kg)

#define	SDT_MICRO 0.000001
	One millionth, small value often used instead of 0 to avoid division errors.

#define	SDT_QUIET 0.00003
	Gain factor roughly corresponding to a -90dB attenuation.

#define	SDT_ver 078
	SDT version number.

#define	SDT_ver_str "078"
	SDT version string.

#define	SDT_PI 3.141592653589793
	Value of Pi.

#define	SDT_TWOPI 6.283185307179586
	Value of 2 * Pi.

#define	SDT_EULER 2.718281828459045
	Euler number.

#define	SDT_SQRT2 1.4142135623730951
	Square root of 2.

#define	SDT_MACH1 340.29
	Mach 1, speed of sound in air under normal atmospheric conditions (m/s)

#define	SDT_EARTH 9.81
	Earth gravity (N/Kg)

#define	SDT_MICRO 0.000001
	One millionth, small value often used instead of 0 to avoid division errors.

#define	SDT_QUIET 0.00003
	Gain factor roughly corresponding to a -90dB attenuation.

Functions
void	SDT_setSampleRate (double sampleRate)
	Sets the sample rate. More...

void	SDT_blackman (double *sig, int n)
	Applies a Blackman window to a chunk of samples. Applies a Blackman window to a chunk of samples. More...

unsigned int	SDT_bitReverse (unsigned int u, unsigned int bits)
	Reverses the bit order of an unsigned integer of given bit length. More...

long	SDT_clip (long x, long min, long max)
	Clips an integer value. Limits the range of an integer value between a given lower bound and upper bound. More...

double	SDT_expRand (double lambda)
	Exponential random number generator. Generates random numbers, following an exponential distribution. More...

double	SDT_fclip (double x, double min, double max)
	Clips a floating point value. Limits the range of a floating point value between a given lower bound and upper bound. More...

double	SDT_frand ()
	Uniform random number generator. Generates random numbers, following a uniform distribution. More...

void	SDT_gaussian1D (double *x, double sigma, int n)
	One-dimensional Gaussian kernel. One-dimensional Gaussian kernel. The Gaussian function is computed in the [-1,1] interval with 0 mean and the given standard deviation. The output is normalized so that the sum of all samples is equal to 1. More...

double	SDT_gravity (double mass)
	Computes earth gravity force. Computes the earth gravity force acting on an object of a given mass. More...

void	SDT_hanning (double *sig, int n)
	Applies a Hanning window to a chunk of samples. Applies a Hanning window to a chunk of samples. More...

void	SDT_haar (double *sig, long n)
	Computes a direct Haar Wavelet Transform of the incoming signal (in place). More...

void	SDT_ihaar (double *sig, long n)
	Computes an inverse Haar Wavelet Transform of the incoming signal (in place). More...

double	SDT_kinetic (double mass, double velocity)
	Computes kinetic energy. Computes the kinetic energy of an object, given its mass and velocity. More...

unsigned int	SDT_nextPow2 (unsigned int u)
	Returns the smallest power of 2 greater or equal than u. More...

double	SDT_normalize (double x, double min, double max)
	Rescales a value of known range into the [0.0, 1.0] interval. Rescales a value of known range into the [0.0, 1.0] interval. More...

void	SDT_normalizeWindow (double *sig, int n)
	Normalizes samples in a window so that their sum is equal to 1. More...

void	SDT_ones (double *sig, int n)
	Fills a buffer with ones. Fills a buffer with ones. More...

double	SDT_rank (double *x, int n, int k)
	Finds the kth smallest value in the input array. Finds the kth smallest value in the input array. More...

void	SDT_removeDC (double *sig, int n)
	Removes the global average from samples in a window. More...

int	SDT_roi (double sig, int peaks, int *bounds, int d, int n)
	Finds regions of influence (local maxima and minima) in a buffer. Finds regions of influence (local maxima and minima) in a buffer. More...

double	SDT_samplesInAir (double length)
	Time needed to travel the given distance at Mach 1. Computes the amount of time, in samples, needed by a sound wave propagating in air to travel a given distance. Particularly useful to set the delay times of comb filters and/or digital waveguides representing hollow cavities. More...

double	SDT_scale (double x, double srcMin, double srcMax, double dstMin, double dstMax, double gamma)
	Rescales a value from a source range to a target range. Rescales a value from a source range to a target range. More...

int	SDT_signum (double x)
	Computes the signum function. Computes the signum function. More...

void	SDT_sinc (double *sig, double w, int n)
	Applies a sinc window (sin(wt)/(wt)) to a chunk of samples. Applies a sinc window (sin(wt)/(wt)) to a chunk of samples. More...

double	SDT_truePeakPos (double *sig, int peak)
	Performs quadratic interpolation to estimate the true position of a peak. Performs quadratic interpolation to estimate the true position of a peak. More...

double	SDT_truePeakValue (double *sig, int peak)
	Performs quadratic interpolation to estimate the true amplitude value of a peak. Performs quadratic interpolation to estimate the true amplitude value of a peak. More...

double	SDT_wrap (double x)
	Wraps a phase in the range -pi/pi. Wraps a phase in the range -pi/pi. More...

void	SDT_zeros (double *sig, int n)
	Fills a buffer with zeros. Fills a buffer with zeros. More...

Variables
double	SDT_sampleRate
	Sampling frequency (Hz)

double	SDT_timeStep
	Sampling period (s)

double	SDT_sampleRate
	Sampling frequency (Hz)

double	SDT_timeStep
	Sampling period (s)

Detailed Description

Macros, variables and functions commonly used by all the SDT objects. SDTCommon.h should always be included when using other SDT modules.

Function Documentation

unsigned int SDT_bitReverse	(	unsigned int	u,
		unsigned int	bits
	)

Reverses the bit order of an unsigned integer of given bit length.

Parameters

[in]	u	Input value
[in]	bits	Number of bits to reverse

Returns: Unsigned integer with reversed bits

void SDT_blackman	(	double *	sig,
		int	n
	)

Applies a Blackman window to a chunk of samples. Applies a Blackman window to a chunk of samples.

Parameters

[in,out]	sig	samples to window
[in]	n	window size

long SDT_clip	(	long	x,
		long	min,
		long	max
	)

Clips an integer value. Limits the range of an integer value between a given lower bound and upper bound.

Parameters

[in]	x	Integer value to clip
[in]	min	Lower limit
[in]	max	Upper limit

Returns: Clipped integer value

double SDT_expRand ( double lambda )

Exponential random number generator. Generates random numbers, following an exponential distribution.

Parameters

[in] lambda Rate of the exponential distribution.

Returns: Randomly generated value [0.0, +inf]

double SDT_fclip	(	double	x,
		double	min,
		double	max
	)

Clips a floating point value. Limits the range of a floating point value between a given lower bound and upper bound.

Parameters

[in]	x	Floating point value to clip
[in]	min	Lower limit
[in]	max	Upper limit

Returns: Clipped floating point value

double SDT_frand ( )

Uniform random number generator. Generates random numbers, following a uniform distribution.

Returns: Randomly generated value [0.0, 1.0]

void SDT_gaussian1D	(	double *	x,
		double	sigma,
		int	n
	)

One-dimensional Gaussian kernel. One-dimensional Gaussian kernel. The Gaussian function is computed in the [-1,1] interval with 0 mean and the given standard deviation. The output is normalized so that the sum of all samples is equal to 1.

Parameters

[out]	x	pointer to the kernel samples
[in]	sigma	standard deviation of the Gaussian function
[in]	n	kernel size

double SDT_gravity ( double mass )

Computes earth gravity force. Computes the earth gravity force acting on an object of a given mass.

Parameters

[in] mass Mass of the object (Kg)

Returns: Earth gravity force (N)

void SDT_haar	(	double *	sig,
		long	n
	)

Computes a direct Haar Wavelet Transform of the incoming signal (in place).

Parameters

[in,out]	sig	incoming signals
[in]	n	window size

void SDT_hanning	(	double *	sig,
		int	n
	)

Applies a Hanning window to a chunk of samples. Applies a Hanning window to a chunk of samples.

Parameters

[in,out]	sig	samples to window
[in]	n	window size

void SDT_ihaar	(	double *	sig,
		long	n
	)

Computes an inverse Haar Wavelet Transform of the incoming signal (in place).

Parameters

[in,out]	sig	incoming signals
[in]	n	window size

double SDT_kinetic	(	double	mass,
		double	velocity
	)

Computes kinetic energy. Computes the kinetic energy of an object, given its mass and velocity.

Parameters

[in]	mass	Mass of the object (Kg)
[in]	velocity	Velocity of the object (m/s)

Returns: Kinetic energy (J)

unsigned int SDT_nextPow2 ( unsigned int u )

Returns the smallest power of 2 greater or equal than u.

Parameters

[in] u Input value

Returns: Smallest power of 2 greater or equal than u

double SDT_normalize	(	double	x,
		double	min,
		double	max
	)

Rescales a value of known range into the [0.0, 1.0] interval. Rescales a value of known range into the [0.0, 1.0] interval.

Parameters

[in]	x	Value to normalize
[in]	min	Lower bound
[in]	max	Upper bound

Returns: Value rescaled from [min, max] to [0.0, 1.0]

void SDT_normalizeWindow	(	double *	sig,
		int	n
	)

Normalizes samples in a window so that their sum is equal to 1.

Parameters

[in,out]	sig	window to normalize
[in]	n	window size

void SDT_ones	(	double *	sig,
		int	n
	)

Fills a buffer with ones. Fills a buffer with ones.

Parameters

[in,out]	sig	pointer to the buffer
[in]	n	buffer size

double SDT_rank	(	double *	x,
		int	n,
		int	k
	)

Finds the kth smallest value in the input array. Finds the kth smallest value in the input array.

Parameters

[in]	x	input array
[in]	n	array size
[in]	k	item rank

Returns: kth smallest value in the array

void SDT_removeDC	(	double *	sig,
		int	n
	)

Removes the global average from samples in a window.

Parameters

[in,out]	sig	window to remove the average from
[in]	n	window size

int SDT_roi	(	double *	sig,
		int *	peaks,
		int *	bounds,
		int	d,
		int	n
	)

Finds regions of influence (local maxima and minima) in a buffer. Finds regions of influence (local maxima and minima) in a buffer.

Parameters

[in]	sig	pointer to the buffer
[out]	peaks	indexes of the local maxima in the buffer
[out]	bounds	indexes of the local minima in the buffer

double SDT_samplesInAir ( double length )

Time needed to travel the given distance at Mach 1. Computes the amount of time, in samples, needed by a sound wave propagating in air to travel a given distance. Particularly useful to set the delay times of comb filters and/or digital waveguides representing hollow cavities.

Parameters

[in] length Distance (m)

Returns: Amount of samples to travel the distance at Mach 1

double SDT_scale	(	double	x,
		double	srcMin,
		double	srcMax,
		double	dstMin,
		double	dstMax,
		double	gamma
	)

Rescales a value from a source range to a target range. Rescales a value from a source range to a target range.

Parameters

[in]	x	Value to rescale
[in]	srcMin	Lower bound of source value
[in]	srcMax	Upper bound of source value
[in]	dstMin	Lower bound of rescaled value
[in]	dstMax	Upper bound of rescaled value
[in]	gamma	Gamma factor

Returns: Value rescaled from [srcMin, srcMax] to [dstMin, dstMax] with gamma factor gamma

void SDT_setSampleRate ( double sampleRate )

Sets the sample rate.

Parameters

[in] sampleRate Sample rate (Hz).

int SDT_signum ( double x )

Computes the signum function. Computes the signum function.

Parameters

[in] x Input value

Returns: Signum of x

void SDT_sinc	(	double *	sig,
		double	w,
		int	n
	)

Applies a sinc window (sin(wt)/(wt)) to a chunk of samples. Applies a sinc window (sin(wt)/(wt)) to a chunk of samples.

Parameters

[in,out]	sig	samples to window
[in]	w	sinc parameter
[in]	n	window size

double SDT_truePeakPos	(	double *	sig,
		int	peak
	)

Performs quadratic interpolation to estimate the true position of a peak. Performs quadratic interpolation to estimate the true position of a peak.

Parameters

[in]	sig	signal buffer
[in]	peak	index of a local maximum

Returns: true peak position

double SDT_truePeakValue	(	double *	sig,
		int	peak
	)

Performs quadratic interpolation to estimate the true amplitude value of a peak. Performs quadratic interpolation to estimate the true amplitude value of a peak.

Parameters

[in]	sig	signal buffer
[in]	peak	index of a local maximum

Returns: true peak value

double SDT_wrap ( double x )

Wraps a phase in the range -pi/pi. Wraps a phase in the range -pi/pi.

Parameters

void SDT_zeros	(	double *	sig,
		int	n
	)

Fills a buffer with zeros. Fills a buffer with zeros.

Parameters

[in,out]	sig	pointer to the buffer
[in]	n	buffer size

Macros

Functions

Variables

Detailed Description

Function Documentation