qlibs::discreteSystem Class Reference

A LTI discrete system object. More...

#include <ltisys.hpp>

Inheritance diagram for qlibs::discreteSystem:

Public Member Functions
virtual	~discreteSystem ()
	discreteSystem (real_t *num, real_t *den, real_t *x, const size_t n_b, const size_t n_a) noexcept
	Constructor for a the discrete LTI system.
template<size_t NB, size_t NA>
	discreteSystem (real_t(&num)[NB], real_t(&den)[NA], real_t *x) noexcept
	Constructor for a the discrete LTI system.
template<size_t NB, size_t NA>
	discreteSystem (discreteTF< NB, NA > &dtf) noexcept
	Constructor for a the discrete LTI system from a transfer function definition.
bool	setup (real_t *num, real_t *den, real_t *x, const size_t n_b, const size_t n_a) noexcept
	Setup and initialize an instance of the discrete LTI system.
template<size_t NB, size_t NA>
bool	setup (real_t(&num)[NB], real_t(&den)[NA], real_t *x)
	Setup and initialize an instance of the discrete LTI system.
template<size_t NB, size_t NA>
bool	setup (discreteTF< NB, NA > &dtf) noexcept
	Setup and initialize an instance of the discrete LTI system from a transfer function definition.
bool	isInitialized (void) const noexcept override
	Check if the LTI discrete system is initialized.
	operator bool () const noexcept
	Check if the LTI discrete system is initialized.
bool	setInitStates (const real_t *xi=nullptr) override
	Set the initial states for the discrete system.
Public Member Functions inherited from qlibs::ltisys
virtual	~ltisys ()
	ltisys ()=default
real_t	excite (real_t u) noexcept
	Drives the LTI system recursively using the provided input sample.
real_t	operator() (const real_t u)
	Drives the LTI system recursively using the provided input sample.
	operator bool () const noexcept
	Check if the LTI system is initialized.
ltisysType	getType (void) const
	Get the LTI system type.
bool	setDelay (real_t *const w, const size_t nD, const real_t initVal=0.0_re) noexcept
	Set the input delay for LTI system.
bool	setSaturation (const real_t minV, const real_t maxV) noexcept
	Setup the output saturation for the LTI system.
Public Member Functions inherited from qlibs::tdl
virtual	~tdl () noexcept=default
	tdl ()=default
	tdl (real_t *const area, const size_t n, const real_t initVal=0.0_re) noexcept
	Constructor for the Tapped Delay Line (TDL) instance.
template<size_t numberOfDelays>
	tdl (real_t(&area)[numberOfDelays], const real_t initVal=0.0_re) noexcept
	Constructor for the Tapped Delay Line (TDL) instance.
void	setup (real_t *const area, const size_t n, const real_t initVal=0.0_re) noexcept
	Setup and initialize a Tapped Delay Line (TDL) instance by setting the default optimal parameters.
template<size_t numberOfDelays>
void	setup (real_t(&area)[numberOfDelays], const real_t initVal=0.0_re) noexcept
	Setup and initialize a Tapped Delay Line (TDL) instance by setting the default optimal parameters.
void	flush (const real_t initVal=0.0_re) noexcept
	Clears all delays from the TDL and sets them to the specified value.
real_t	getOldest (void) const noexcept
	Get the oldest sample from the TDL x(k-n)
real_t	getRecent (void) const noexcept
	Get the most recent sample from the TDL x(k)
real_t	getAtIndex (const size_t i) const noexcept
	Get the specified delayed sample from the TDL x(k-i)
void	insertSample (const real_t sample) noexcept
	Insert a new sample to the TDL removing the oldest sample.
real_t	operator[] (int index) noexcept
	Get the specified delayed sample from the TDL x(k-i)
void	operator() (const real_t sample) noexcept
	Insert a new sample to the TDL removing the oldest sample.
bool	isInitialized (void) const noexcept
	Check if the TDL has been initialized.
	operator bool () const noexcept
	Check if the TDL has been initialized.

Static Public Member Functions
static real_t	updateFIR (real_t *w, const size_t wsize, const real_t x, const real_t *const c=nullptr)
	Evaluate the discrete FIR filter by updating the delay lines of x inside the window w of size wsize with the coefficients given in c. If c it's not supplied, this function just perform the window update.

Detailed Description

A LTI discrete system object.

The instance should be initialized using the discreteSystem::setup() method.

Constructor & Destructor Documentation

~discreteSystem()

virtual qlibs::discreteSystem::~discreteSystem ( )

inlinevirtual

discreteSystem() [1/3]

qlibs::discreteSystem::discreteSystem ( real_t * num, real_t * den, real_t * x, const size_t n_b, const size_t n_a )

inlinenoexcept

Constructor for a the discrete LTI system.

Parameters

[in,out]	num	: An array of nb elements with the numerator coefficients of the transfer function. Coefficients should be given in descending powers of the n or nb-degree polynomial. Coefficients will be normalized internally.
[in,out]	den	An array of or na elements with the denominator coefficients of the transfer function. Coefficients should be given in descending powers of the n or nb-degree polynomial. Coefficients will be normalized internally.
[in,out]	x	Initial conditions of the system. Should be an, an array of type discreteStates with max(na,nb) elements The supplied array will be updated on every invocation of discreteSystem::excite().
[in]	n_b	Number of elements in num

example: \( b_{0}+b_{1}z^{-1}+b_{2}z^{-2}+b_{3}z^{-3}, nb = 4 \)

Parameters

[in]

n_a

Number of elements in den.

example 1: \( a_{0}+a_{1}z^{-1}+a_{2}z^{-2}+a_{3}z^{-3}, na = 4 \)

Note

By default, initial conditions are set to zero. To change the initial conditions to the desired values, use the discreteSystem::setInitStates() method.

discreteSystem() [2/3]

template<size_t NB, size_t NA>

qlibs::discreteSystem::discreteSystem ( real_t(&) num[NB], real_t(&) den[NA], real_t * x )

inlinenoexcept

Constructor for a the discrete LTI system.

Parameters

[in,out]	num	: An array of nb elements with the numerator coefficients of the transfer function. Coefficients should be given in descending powers of the n or nb-degree polynomial. Coefficients will be normalized internally.
[in,out]	den	An array of or na elements with the denominator coefficients of the transfer function. Coefficients should be given in descending powers of the n or nb-degree polynomial. Coefficients will be normalized internally.
[in,out]	x	Initial conditions of the system. Should be an, an array of type discreteStates with max(na,nb) elements The supplied array will be updated on every invocation of discreteSystem::excite().

Note

By default, initial conditions are set to zero. To change the initial conditions to the desired values, use the discreteSystem::setInitStates() method.

discreteSystem() [3/3]

template<size_t NB, size_t NA>

qlibs::discreteSystem::discreteSystem ( discreteTF< NB, NA > & dtf )

inlinenoexcept

Constructor for a the discrete LTI system from a transfer function definition.

Parameters

[in,out]

dtf

: The transfer function definition

Member Function Documentation

isInitialized()

bool qlibs::discreteSystem::isInitialized ( void ) const

inlineoverridevirtualnoexcept

Check if the LTI discrete system is initialized.

Returns

true if the system has been initialized, otherwise return false.

Implements qlibs::ltisys.

operator bool()

qlibs::discreteSystem::operator bool ( ) const

inlineexplicitnoexcept

Check if the LTI discrete system is initialized.

Returns

true if the system has been initialized, otherwise return false.

setInitStates()

bool discreteSystem::setInitStates ( const real_t * xi = nullptr )

overridevirtual

Set the initial states for the discrete system.

Precondition

System should be previously initialized by using the discreteSystem::setup() method

Parameters

[in]

xi

An array of n-elements with the initial state values. User can pass nullptr as argument to set initial conditions equal to zero.

Returns

true on success, otherwise return false.

Implements qlibs::ltisys.

setup() [1/3]

template<size_t NB, size_t NA>

bool qlibs::discreteSystem::setup ( discreteTF< NB, NA > & dtf )

inlinenoexcept

Setup and initialize an instance of the discrete LTI system from a transfer function definition.

Parameters

[in,out]

dtf

: The transfer function definition

Returns

true on success, otherwise return false.

setup() [2/3]

bool discreteSystem::setup ( real_t * num, real_t * den, real_t * x, const size_t n_b, const size_t n_a )

noexcept

Setup and initialize an instance of the discrete LTI system.

Parameters

[in,out]	num	: An array of nb elements with the numerator coefficients of the transfer function. Coefficients should be given in descending powers of the n or nb-degree polynomial. Coefficients will be normalized internally.
[in,out]	den	An array of or na elements with the denominator coefficients of the transfer function. Coefficients should be given in descending powers of the n or nb-degree polynomial. Coefficients will be normalized internally.
[in,out]	x	Initial conditions of the system. Should be an, an array of type discreteStates with max(na,nb) elements The supplied array will be updated on every invocation of discreteSystem::excite().
[in]	n_b	Number of elements in num

example: \( b_{0}+b_{1}z^{-1}+b_{2}z^{-2}+b_{3}z^{-3}, nb = 4 \)

Parameters

[in]

n_a

Number of elements in den.

example 1: \( a_{0}+a_{1}z^{-1}+a_{2}z^{-2}+a_{3}z^{-3}, na = 4 \)

Returns

true on success, otherwise return false.

Note

By default, initial conditions are set to zero. To change the initial conditions to the desired values, use the discreteSystem::setInitStates() method.

setup() [3/3]

template<size_t NB, size_t NA>

bool qlibs::discreteSystem::setup ( real_t(&) num[NB], real_t(&) den[NA], real_t * x )

inline

Setup and initialize an instance of the discrete LTI system.

Parameters

[in,out]	num	: An array of nb elements with the numerator coefficients of the transfer function. Coefficients should be given in descending powers of the n or nb-degree polynomial. Coefficients will be normalized internally.
[in,out]	den	An array of or na elements with the denominator coefficients of the transfer function. Coefficients should be given in descending powers of the n or nb-degree polynomial. Coefficients will be normalized internally.
[in,out]	x	Initial conditions of the system. Should be an, an array of type discreteStates with max(na,nb) elements The supplied array will be updated on every invocation of discreteSystem::excite().

Returns

true on success, otherwise return false.

Note

By default, initial conditions are set to zero. To change the initial conditions to the desired values, use the discreteSystem::setInitStates() method.

updateFIR()

real_t discreteSystem::updateFIR ( real_t * w, const size_t wsize, const real_t x, const real_t *const c = nullptr )

static

Evaluate the discrete FIR filter by updating the delay lines of x inside the window w of size wsize with the coefficients given in c. If c it's not supplied, this function just perform the window update.

Parameters

[in,out]	w	An array of wsize elements that holds the window with the delay lines of x.
[in]	wsize	The number of elements of w.
[in]	x	A sample of the input signal.
[in]	c	An array of wsize elements with the coefficients of the FIR filter. Coefficients should be given in descending powers of the nth-degree polynomial. To ignore pass nullptr.

Returns

If c is provided, returns the evaluation of the FIR filter. otherwise return the sum of the updated window w.