mirror of
https://github.com/cookiengineer/audacity
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92 lines
2.5 KiB
C++
92 lines
2.5 KiB
C++
/***************************************************/
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/*! \class PoleZero
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\brief STK one-pole, one-zero filter class.
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This protected Filter subclass implements
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a one-pole, one-zero digital filter. A
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method is provided for creating an allpass
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filter with a given coefficient. Another
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method is provided to create a DC blocking filter.
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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_POLEZERO_H
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#define STK_POLEZERO_H
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#include "Filter.h"
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namespace Nyq
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{
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class PoleZero : protected Filter
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{
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public:
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//! Default constructor creates a first-order pass-through filter.
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PoleZero();
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//! Class destructor.
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~PoleZero();
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//! Clears the internal states 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 b[1] coefficient value.
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void setB1(StkFloat b1);
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//! Set the a[1] coefficient value.
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void setA1(StkFloat a1);
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//! Set the filter for allpass behavior using \e coefficient.
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/*!
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This method uses \e coefficient to create an allpass filter,
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which has unity gain at all frequencies. Note that the \e
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coefficient magnitude must be less than one to maintain stability.
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*/
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void setAllpass(StkFloat coefficient);
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//! Create a DC blocking filter with the given pole position in the z-plane.
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/*!
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This method sets the given pole position, together with a zero
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at z=1, to create a DC blocking filter. \e thePole should be
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close to one to minimize low-frequency attenuation.
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*/
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void setBlockZero(StkFloat thePole = 0.99);
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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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