yase::IIRFilter Class Reference

#include <iir_filter.hh>

Inheritance diagram for yase::IIRFilter:

Collaboration diagram for yase::IIRFilter:

Detailed Description

This module implements an Infinite Impulse Response (IIR) filter.

The IIR operates according to the difference equation

  a[0]*y[n] + a[1]*y[n-1] + ... + a[p]*y[n-p] = b[0]*u[n] + b[1]*u[n-1] + ... + b[q]*u[n-q].

The input is u[n] and the output is y[n]. Previous values of u and y are remembered by the module. There are two constructors. One takes integers p and q, specifying the feedforward and feedback orders respectively. A later call to set_coefficients is needed in this case. The other constructor takes a list of the coefficients directly.

For example, a simple averaging filter (which is actually a FIR filter) can be constructed with

  IIRFilter filter({2},{1,1});

Parameters

[in]	signal
[out]	signal

Public Member Functions
	IIRFilter (int P, int Q)
	IIRFilter (vector< double > A, vector< double > B)
void	init ()
void	update ()
void	set_coefficients (vector< double > A, vector< double > B)
Public Member Functions inherited from yase::Module
virtual void	init ()=0
virtual void	update ()=0
int	add_input (string name)
int	add_output (string name)
int	get_input_index (string name) const
string	get_input_name (int index) const
string	get_output_name (int index) const
int	get_output_index (string name) const
void	set_input (string name, double value)
void	set_input (int index, double value)
double	get_input (int index) const
double	get_input (string name) const
double	get_output (string name) const
double	get_output (int index) const
void	set_output (int index, double value)
void	copy_inputs (const Module &source)
void	copy_outputs (Module &destination) const
void	configure (std::vector< std::tuple< string, double > > assignments)
int	num_inputs () const
int	num_outputs () const
void	emit (Event e)
void	set_ts (double s)
double	get_ts ()

Constructor & Destructor Documentation

IIRFilter() [1/2]

yase::IIRFilter::IIRFilter	(	int	P,
		int	Q
	)

Define a new IIR filter with feedforward order P and feedback order Q. Call IIRFilter::set_coefficients to set the value of the coefficents.

Parameters

P	Feedforward order
Q	Feedback order.

IIRFilter() [2/2]

yase::IIRFilter::IIRFilter	(	vector< double >	A,
		vector< double >	B
	)

Define a new IIR filter feedforward coefficients A and feedback coefficients B.

Parameters

A	Feedforward coefficients.
B	Feedback coefficients.

Member Function Documentation

init()

void yase::IIRFilter::init ( )

virtual

This method should be overridden by derived classes. It will usually be called once, after all modules and connections objects have been added to a synthesizer, but before the synthesizer starts running.

Implements yase::Module.

Reimplemented in yase::Resonator.

set_coefficients()

void yase::IIRFilter::set_coefficients	(	vector< double >	A,
		vector< double >	B
	)

Set the coefficients of the filter.

Parameters

A	Feedforward coefficients.
B	Feedback coefficients.

update()

void yase::IIRFilter::update ( )

virtual

This method should be overridden by derived classes. It will be called repeatedly by a synthesizer at a frequency determined by SAMPLE_RATE.

Implements yase::Module.

Reimplemented in yase::Resonator.

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

• include/iir_filter.hh
• src/iir_filter.cc