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 override
	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)
	Drives the LTI system recursively using the input signal provided.
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 ()
	tdl ()=default
	tdl (real_t *const area, const size_t n, const real_t initVal=0.0_re)
	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.
const 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
	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: \( a_{0}+a_{1}z^{-1}+a_{2}z^{-2}+a_{3}z^{-3}, na = 4 \)

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.

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().

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.

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

inlineoverridevirtual

Check if the LTI discrete system is initialized.

Returns

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

Implements qlibs::ltisys.

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.