#include <BandPass.h>

Inheritance diagram for Kwave::BandPass:

Collaboration diagram for Kwave::BandPass:

Public Slots
void	input (Kwave::SampleArray data)

void	setFrequency (const QVariant fc)

void	setBandwidth (const QVariant bw)

Signals
void	output (Kwave::SampleArray data)

Signals inherited from Kwave::StreamObject
void	attributeChanged (const QVariant value)

Public Member Functions
	BandPass ()

virtual	~BandPass () Q_DECL_OVERRIDE

virtual void	goOn () Q_DECL_OVERRIDE

virtual double	at (double f) Q_DECL_OVERRIDE

Public Member Functions inherited from Kwave::SampleSource
	SampleSource (QObject *parent=Q_NULLPTR)

virtual	~SampleSource ()

virtual bool	done () const

Public Member Functions inherited from Kwave::StreamObject
	StreamObject (QObject *parent=Q_NULLPTR)

virtual	~StreamObject ()

virtual unsigned int	tracks () const

virtual Kwave::StreamObject *	operator[] (unsigned int track)

virtual unsigned int	tracksOfPort (const char *port) const

virtual Kwave::StreamObject *	port (const char *port, unsigned int track)

virtual unsigned int	blockSize () const

void	setAttribute (const char *attribute, const QVariant &value)

Public Member Functions inherited from Kwave::TransmissionFunction
virtual	~TransmissionFunction ()

Private Member Functions
void	initFilter ()

void	setfilter_2polebp (double freq, double R)

Private Attributes
Kwave::SampleArray	m_buffer

double	m_frequency

double	m_bandwidth

struct {
double cx

double cx1

double cx2

double cy1

double cy2

double x

double x1

double x2

double y

double y1

double y2

}	m_filter

Additional Inherited Members
Static Public Member Functions inherited from Kwave::StreamObject
static void	setInteractive (bool interactive)

Detailed Description

Definition at line 36 of file BandPass.h.

Constructor & Destructor Documentation

◆ BandPass()

Kwave::BandPass::BandPass ( )

Constructor

Definition at line 29 of file BandPass.cpp.

References initFilter(), m_bandwidth, m_frequency, and setfilter_2polebp().

     :Kwave::SampleSource(Q_NULLPTR), m_buffer(blockSize()),
     m_frequency(0.5), m_bandwidth(0.1)
 {
     initFilter();
     setfilter_2polebp(m_frequency, m_bandwidth);
 }

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◆ ~BandPass()

Kwave::BandPass::~BandPass ( )

virtual

Destructor

Definition at line 38 of file BandPass.cpp.

39 {

40 }

Member Function Documentation

◆ at()

double Kwave::BandPass::at ( double f )

virtual

See also: TransmissionFunction::at()

Implements Kwave::TransmissionFunction.

Definition at line 49 of file BandPass.cpp.

References m_filter.

 {
     /*
      * filter function as extracted from the aRts code:
      *
      * y[t] = cx*x[t] + cx1*x[t-1] + cx2*x[t-2]
      *                + cy1*y[t-1] + cy2*y[t-2];
      *
      * convert filter coefficients to our notation:
      */
     double a0, a1, a2, b1, b2;
     a0 = m_filter.cx;
     a1 = m_filter.cx1;
     a2 = m_filter.cx2;
     b1 = m_filter.cy1;
     b2 = m_filter.cy2;
 
     /*
      *        a0*z^2 + a1*z + a2
      * H(z) = ------------------   | z = e ^ (j*2*pi*f)
      *          z^2 - b1*z - b0
      */
     std::complex<double> h;
     std::complex<double> w;
     std::complex<double> j(0.0,1.0);
     std::complex<double> z;
 
     w = f;
     z = std::exp(j*w);
 
     // get h[z] at z=e^jw
     h = 0.95 * (a0 * (z*z) + (a1*z) + a2) / ((z*z) - (b1*z) - b2);
 
     return sqrt(std::norm(h));
 }

◆ goOn()

void Kwave::BandPass::goOn ( )

virtual

does the calculation

Implements Kwave::SampleSource.

Definition at line 43 of file BandPass.cpp.

References m_buffer, and output().

 {
     emit output(m_buffer);
 }

◆ initFilter()

void Kwave::BandPass::initFilter ( )

private

reset/initialize the filter coefficients

Definition at line 86 of file BandPass.cpp.

References m_filter.

Referenced by BandPass(), setBandwidth(), and setFrequency().

 {
     m_filter.x1 = 0.0;
     m_filter.x2 = 0.0;
     m_filter.y1 = 0.0;
     m_filter.y2 = 0.0;
     m_filter.y  = 0.0;
 }

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◆ input

void Kwave::BandPass::input ( Kwave::SampleArray data )

slot

receives input data

Definition at line 110 of file BandPass.cpp.

References double2sample(), m_bandwidth, m_buffer, m_filter, m_frequency, Kwave::SampleArray::resize(), sample2double(), setfilter_2polebp(), and Kwave::SampleArray::size().

 {
     const Kwave::SampleArray &in = data;
 
     bool ok = m_buffer.resize(in.size());
     Q_ASSERT(ok);
     Q_UNUSED(ok);
 
     setfilter_2polebp(m_frequency, m_bandwidth);
 
     Q_ASSERT(in.size() == m_buffer.size());
 
     for (unsigned i = 0; i < in.size(); ++i)
     {
         // do the filtering
         m_filter.x = sample2double(in[i]);
         m_filter.y =
             m_filter.cx  * m_filter.x  +
             m_filter.cx1 * m_filter.x1 +
             m_filter.cx2 * m_filter.x2 +
             m_filter.cy1 * m_filter.y1 +
             m_filter.cy2 * m_filter.y2;
         m_filter.x2 = m_filter.x1;
         m_filter.x1 = m_filter.x;
         m_filter.y2 = m_filter.y1;
         m_filter.y1 = m_filter.y;
         m_buffer[i] = double2sample(0.95 * m_filter.y);
     }
 }

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◆ output

void Kwave::BandPass::output ( Kwave::SampleArray data )

signal

emits a block with the filtered data

Referenced by goOn().

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◆ setBandwidth

void Kwave::BandPass::setBandwidth ( const QVariant bw )

slot

Sets the bandwidth, normed to [0...2Pi]. The calculation is: bw = bandwidth [Hz] * 2 * Pi / f_sample [Hz]. The default setting is 0.1.

Definition at line 152 of file BandPass.cpp.

References initFilter(), m_bandwidth, m_frequency, and setfilter_2polebp().

Referenced by Kwave::BandPassDialog::updateDisplay().

 {
     double new_bw = QVariant(bw).toDouble();
     if (qFuzzyCompare(new_bw, m_bandwidth)) return; // nothing to do
 
     m_bandwidth = new_bw;
     initFilter();
     setfilter_2polebp(m_frequency, m_bandwidth);
 }

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◆ setfilter_2polebp()

void Kwave::BandPass::setfilter_2polebp	(	double	freq,
		double	R
	)

private

set the coefficients for a given frequency

Parameters

freq	normed frequency
R	normed bandwidth

Definition at line 100 of file BandPass.cpp.

References m_filter.

Referenced by BandPass(), input(), setBandwidth(), and setFrequency().

 {
     m_filter.cx  = 1.0 - R;
     m_filter.cx1 = 0.0;
     m_filter.cx2 = - (1.0 - R) * R;
     m_filter.cy1 = 2.0 * R * cos(freq);
     m_filter.cy2 = -R * R;
 }

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◆ setFrequency

void Kwave::BandPass::setFrequency ( const QVariant fc )

slot

Sets the center frequency, normed to [0...2Pi]. The calculation is: fc = frequency [Hz] * 2 * Pi / f_sample [Hz]. The default setting is 0.5.

Definition at line 141 of file BandPass.cpp.

References initFilter(), m_bandwidth, m_frequency, and setfilter_2polebp().

Referenced by Kwave::BandPassDialog::updateDisplay().

 {
     double new_freq = QVariant(fc).toDouble();
     if (qFuzzyCompare(new_freq, m_frequency)) return; // nothing to do
 
     m_frequency = new_freq;
     initFilter();
     setfilter_2polebp(m_frequency, m_bandwidth);
 }

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Member Data Documentation

◆ cx

double Kwave::BandPass::cx

Definition at line 103 of file BandPass.h.

◆ cx1

double Kwave::BandPass::cx1

Definition at line 103 of file BandPass.h.

◆ cx2

double Kwave::BandPass::cx2

Definition at line 103 of file BandPass.h.

◆ cy1

double Kwave::BandPass::cy1

Definition at line 103 of file BandPass.h.

◆ cy2

double Kwave::BandPass::cy2

Definition at line 103 of file BandPass.h.

◆ m_bandwidth

double Kwave::BandPass::m_bandwidth

private

bandwidth

Definition at line 99 of file BandPass.h.

Referenced by BandPass(), input(), setBandwidth(), and setFrequency().

◆ m_buffer

Kwave::SampleArray Kwave::BandPass::m_buffer

private

buffer for input

Definition at line 93 of file BandPass.h.

Referenced by goOn(), and input().

◆ m_filter

struct { ... } Kwave::BandPass::m_filter

structure with the filter coefficients

Referenced by at(), initFilter(), input(), and setfilter_2polebp().

◆ m_frequency

double Kwave::BandPass::m_frequency

private

center frequency

Definition at line 96 of file BandPass.h.

Referenced by BandPass(), input(), setBandwidth(), and setFrequency().

◆ x

double Kwave::BandPass::x

Definition at line 104 of file BandPass.h.

◆ x1

double Kwave::BandPass::x1

Definition at line 104 of file BandPass.h.

◆ x2

double Kwave::BandPass::x2

Definition at line 104 of file BandPass.h.

◆ y

double Kwave::BandPass::y

Definition at line 104 of file BandPass.h.

◆ y1

double Kwave::BandPass::y1

Definition at line 104 of file BandPass.h.

◆ y2

double Kwave::BandPass::y2

Definition at line 104 of file BandPass.h.

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

plugins/band_pass/BandPass.h
plugins/band_pass/BandPass.cpp

Public Slots

Signals

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ BandPass()

◆ ~BandPass()

Member Function Documentation

◆ at()

◆ goOn()

◆ initFilter()

◆ input

◆ output

◆ setBandwidth

◆ setfilter_2polebp()

◆ setFrequency

Member Data Documentation

◆ cx

◆ cx1

◆ cx2

◆ cy1

◆ cy2

◆ m_bandwidth

◆ m_buffer

◆ m_filter

◆ m_frequency

◆ x

◆ x1

◆ x2

◆ y

◆ y1

◆ y2