NormalizingIIRFilter< NB, NA, T > Class Template Reference

#include <Filters/IIRFilter.hpp>

Detailed Description

template<uint8_t NB, uint8_t NA, class T>
class NormalizingIIRFilter< NB, NA, T >

Infinite Impulse Response filter implementation that normalizes the coefficients upon initialization.

This class is faster than NonNormalizingIIRFilter, because each filter iteration involves only addition and multiplication, no divisions.
It works great for floating point numbers, but might be less ideal for integer types, because it can create large rounding errors on the coefficients.

Implements the following difference equation using the Direct-Form 1 implementation:

\[ y[n] = \frac{1}{a_0} \left(\sum_{i=0}^{N_b-1} b_i \cdot x[n-i] - \sum_{i=1}^{N_a-1} a_i \cdot y[n-i] \right) \]

Definition at line 127 of file IIRFilter.hpp.

Collaboration diagram for NormalizingIIRFilter< NB, NA, T >:

Public Member Functions
	NormalizingIIRFilter (const AH::Array< T, NB > &b_coefficients, const AH::Array< T, NA > &a_coefficients)
	Construct a new Normalizing IIR Filter object. More...
	NormalizingIIRFilter (const TransferFunction< NB, NA, T > &tf)
T	operator() (T input)
	Update the internal state with the new input \( x[n] \) and return the new output \( y[n] \). More...

Private Attributes
uint8_t	index_b = 0
uint8_t	index_a = 0
AH::Array< T, NB >	x = {}
AH::Array< T, MA >	y = {}
AH::Array< T, 2 *NB - 1 >	b_coefficients
AH::Array< T, 2 *MA - 1 >	a_coefficients

Static Private Attributes
static constexpr uint8_t	MA = NA - 1

Constructor & Destructor Documentation

NormalizingIIRFilter() [1/2]

NormalizingIIRFilter ( const AH::Array< T, NB > &  b_coefficients, const AH::Array< T, NA > &  a_coefficients  )

inline

Construct a new Normalizing IIR Filter object.

The coefficients \( b \) and \( a \) can be derived from the transfer function:

\[ H(z) = \frac{b_0 + b_1 z^{-1} + \ldots + b_{N_b} z ^{-N_b}} {a_0 + a_1 z^{-1} + \ldots + a_{N_b} z ^{-N_a}} \]

Parameters

b_coefficients	The coefficients of the transfer function numerator.
a_coefficients	The coefficients of the transfer function denominator.

Definition at line 145 of file IIRFilter.hpp.

NormalizingIIRFilter() [2/2]

NormalizingIIRFilter ( const TransferFunction< NB, NA, T > &  tf )

inline

Definition at line 156 of file IIRFilter.hpp.

Member Function Documentation

operator()()

T operator() ( T  input )

inline

Update the internal state with the new input \( x[n] \) and return the new output \( y[n] \).

Parameters

input

The new input \( x[n] \).

Returns

The new output \( y[n] \).

Definition at line 167 of file IIRFilter.hpp.

Member Data Documentation

MA

constexpr uint8_t MA = NA - 1

staticconstexprprivate

Definition at line 200 of file IIRFilter.hpp.

index_b

uint8_t index_b = 0

private

Definition at line 201 of file IIRFilter.hpp.

index_a

uint8_t index_a = 0

private

Definition at line 201 of file IIRFilter.hpp.

x

AH::Array<T, NB> x = {}

private

Definition at line 202 of file IIRFilter.hpp.

y

AH::Array<T, MA> y = {}

private

Definition at line 203 of file IIRFilter.hpp.

b_coefficients

AH::Array<T, 2 * NB - 1> b_coefficients

private

Definition at line 204 of file IIRFilter.hpp.

a_coefficients

AH::Array<T, 2 * MA - 1> a_coefficients

private

Definition at line 205 of file IIRFilter.hpp.

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

• IIRFilter.hpp