mirror of
https://github.com/cookiengineer/audacity
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85 lines
2.2 KiB
C++
85 lines
2.2 KiB
C++
/***************************************************/
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/*! \class OnePole
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\brief STK one-pole filter class.
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This protected Filter subclass implements
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a one-pole digital filter. A method is
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provided for setting the pole position along
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the real axis of the z-plane while maintaining
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a constant peak filter gain.
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by Perry R. Cook and Gary P. Scavone, 1995 - 2005.
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*/
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/***************************************************/
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#ifndef STK_ONEPOLE_H
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#define STK_ONEPOLE_H
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#include "Filter.h"
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namespace Nyq
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{
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class OnePole : protected Filter
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{
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public:
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//! Default constructor creates a first-order low-pass filter.
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OnePole();
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//! Overloaded constructor which sets the pole position during instantiation.
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OnePole( StkFloat thePole );
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//! Class destructor.
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~OnePole();
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//! Clears the internal state of the filter.
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void clear(void);
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//! Set the b[0] coefficient value.
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void setB0(StkFloat b0);
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//! Set the a[1] coefficient value.
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void setA1(StkFloat a1);
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//! Set the pole position in the z-plane.
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/*!
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This method sets the pole position along the real-axis of the
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z-plane and normalizes the coefficients for a maximum gain of one.
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A positive pole value produces a low-pass filter, while a negative
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pole value produces a high-pass filter. This method does not
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affect the filter \e gain value.
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*/
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void setPole(StkFloat thePole);
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//! Set the filter gain.
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/*!
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The gain is applied at the filter input and does not affect the
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coefficient values. The default gain value is 1.0.
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*/
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void setGain(StkFloat gain);
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//! Return the current filter gain.
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StkFloat getGain(void) const;
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//! Return the last computed output value.
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StkFloat lastOut(void) const;
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//! Input one sample to the filter and return one output.
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StkFloat tick(StkFloat sample);
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//! Take a channel of the StkFrames object as inputs to the filter and replace with corresponding outputs.
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/*!
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The \c channel argument should be zero or greater (the first
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channel is specified by 0). An StkError will be thrown if the \c
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channel argument is equal to or greater than the number of
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channels in the StkFrames object.
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*/
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StkFrames& tick( StkFrames& frames, unsigned int channel = 0 );
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};
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} // namespace Nyq
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#endif
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