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/***************************************************************************
NotchFilter.h - transmission function of a notch filter
-------------------
begin : Thu Jun 19 2003
copyright : (C) 2003 by Dave Flogeras
email : d.flogeras@unb.ca
filter functions:
Copyright (C) 1998 Juhana Sadeharju <kouhia@nic.funet.fi>
***************************************************************************/
/***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************/
#ifndef NOTCH_FILTER_H
#define NOTCH_FILTER_H
#include "config.h"
#include <QObject>
#include <QVariant>
#include "libkwave/SampleArray.h"
#include "libkwave/SampleSource.h"
#include "libkwave/TransmissionFunction.h"
namespace Kwave
{
class NotchFilter: public Kwave::SampleSource,
public Kwave::TransmissionFunction
{
Q_OBJECT
public:
/** Constructor */
NotchFilter();
/** Destructor */
~NotchFilter() override;
/** does the calculation */
void goOn() override;
/** @see TransmissionFunction::at() */
double at(double f) override;
signals:
/** emits a block with the filtered data */
void output(Kwave::SampleArray data);
public slots:
/** receives input data */
void input(Kwave::SampleArray data);
/**
* 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.
*/
void setFrequency(const QVariant fc);
/**
* Sets the bandwidth, normed to [0...2Pi]. The calculation is:
* bw = bandwidth [Hz] * 2 * Pi / f_sample [Hz].
* The default setting is 0.1.
*/
void setBandwidth(const QVariant bw);
private:
/** reset/initialize the filter coefficients */
void initFilter();
/**
* set the coefficients for a given frequency
* @param freq normed frequency
* @param bw normed bandwidth
*/
void setfilter_peaknotch2(double freq, double bw);
private:
/** buffer for input */
Kwave::SampleArray m_buffer;
/** cutoff frequency [0...PI] */
double m_f_cutoff;
/** bandwidth of the notch */
double m_f_bw;
/** structure with the filter coefficients */
struct {
double cx,cx1,cx2,cy1,cy2;
double x,x1,x2,y,y1,y2;
} m_filter;
};
}
#endif /* NOTCH_FILTER_H */
//***************************************************************************
//***************************************************************************
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