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stk::PoleZero Class Reference

STK one-pole, one-zero filter class. More...

#include <PoleZero.h>

Inheritance diagram for stk::PoleZero:
stk::Filter stk::Stk

Public Member Functions

 PoleZero ()
 Default constructor creates a first-order pass-through filter.
 
 ~PoleZero ()
 Class destructor.
 
void setB0 (StkFloat b0)
 Set the b[0] coefficient value.
 
void setB1 (StkFloat b1)
 Set the b[1] coefficient value.
 
void setA1 (StkFloat a1)
 Set the a[1] coefficient value.
 
void setCoefficients (StkFloat b0, StkFloat b1, StkFloat a1, bool clearState=false)
 Set all filter coefficients.
 
void setAllpass (StkFloat coefficient)
 Set the filter for allpass behavior using coefficient. More...
 
void setBlockZero (StkFloat thePole=0.99)
 Create a DC blocking filter with the given pole position in the z-plane. More...
 
StkFloat lastOut (void) const
 Return the last computed output value.
 
StkFloat tick (StkFloat input)
 Input one sample to the filter and return one output.
 
StkFramestick (StkFrames &frames, unsigned int channel=0)
 Take a channel of the StkFrames object as inputs to the filter and replace with corresponding outputs. More...
 
- Public Member Functions inherited from stk::Filter
 Filter (void)
 Class constructor.
 
unsigned int channelsIn (void) const
 Return the number of input channels for the class.
 
unsigned int channelsOut (void) const
 Return the number of output channels for the class.
 
virtual void clear (void)
 Clears all internal states of the filter.
 
void setGain (StkFloat gain)
 Set the filter gain. More...
 
StkFloat getGain (void) const
 Return the current filter gain.
 
StkFloat phaseDelay (StkFloat frequency)
 Return the filter phase delay at the specified frequency. More...
 
const StkFrameslastFrame (void) const
 Return an StkFrames reference to the last output sample frame.
 
- Public Member Functions inherited from stk::Stk
void ignoreSampleRateChange (bool ignore=true)
 A function to enable/disable the automatic updating of class data when the STK sample rate changes. More...
 

Additional Inherited Members

- Static Public Member Functions inherited from stk::Stk
static StkFloat sampleRate (void)
 Static method that returns the current STK sample rate.
 
static void setSampleRate (StkFloat rate)
 Static method that sets the STK sample rate. More...
 
static std::string rawwavePath (void)
 Static method that returns the current rawwave path.
 
static void setRawwavePath (std::string path)
 Static method that sets the STK rawwave path.
 
static void swap16 (unsigned char *ptr)
 Static method that byte-swaps a 16-bit data type.
 
static void swap32 (unsigned char *ptr)
 Static method that byte-swaps a 32-bit data type.
 
static void swap64 (unsigned char *ptr)
 Static method that byte-swaps a 64-bit data type.
 
static void sleep (unsigned long milliseconds)
 Static cross-platform method to sleep for a number of milliseconds.
 
static bool inRange (StkFloat value, StkFloat min, StkFloat max)
 Static method to check whether a value is within a specified range.
 
static void handleError (const char *message, StkError::Type type)
 Static function for error reporting and handling using c-strings.
 
static void handleError (std::string message, StkError::Type type)
 Static function for error reporting and handling using c++ strings.
 
static void showWarnings (bool status)
 Toggle display of WARNING and STATUS messages.
 
static void printErrors (bool status)
 Toggle display of error messages before throwing exceptions.
 
- Static Public Attributes inherited from stk::Stk
static const StkFormat STK_SINT8
 
static const StkFormat STK_SINT16
 
static const StkFormat STK_SINT24
 
static const StkFormat STK_SINT32
 
static const StkFormat STK_FLOAT32
 
static const StkFormat STK_FLOAT64
 
- Protected Member Functions inherited from stk::Stk
 Stk (void)
 Default constructor.
 
virtual ~Stk (void)
 Class destructor.
 
virtual void sampleRateChanged (StkFloat newRate, StkFloat oldRate)
 This function should be implemented in subclasses that depend on the sample rate.
 
void addSampleRateAlert (Stk *ptr)
 Add class pointer to list for sample rate change notification.
 
void removeSampleRateAlert (Stk *ptr)
 Remove class pointer from list for sample rate change notification.
 
void handleError (StkError::Type type) const
 Internal function for error reporting that assumes message in oStream_ variable.
 

Detailed Description

STK one-pole, one-zero filter class.

This class implements a one-pole, one-zero digital filter. A method is provided for creating an allpass filter with a given coefficient. Another method is provided to create a DC blocking filter.

by Perry R. Cook and Gary P. Scavone, 1995–2014.

Member Function Documentation

void stk::PoleZero::setAllpass ( StkFloat  coefficient)

Set the filter for allpass behavior using coefficient.

This method uses coefficient to create an allpass filter, which has unity gain at all frequencies. Note that the coefficient magnitude must be less than one to maintain filter stability.

void stk::PoleZero::setBlockZero ( StkFloat  thePole = 0.99)

Create a DC blocking filter with the given pole position in the z-plane.

This method sets the given pole position, together with a zero at z=1, to create a DC blocking filter. The argument magnitude should be close to (but less than) one to minimize low-frequency attenuation.

StkFrames & stk::PoleZero::tick ( StkFrames frames,
unsigned int  channel = 0 
)
inlinevirtual

Take a channel of the StkFrames object as inputs to the filter and replace with corresponding outputs.

The channel argument must be less than the number of channels in the StkFrames argument (the first channel is specified by 0). However, range checking is only performed if STK_DEBUG is defined during compilation, in which case an out-of-range value will trigger an StkError exception.

Implements stk::Filter.

90 {
91 #if defined(_STK_DEBUG_)
92  if ( channel >= frames.channels() ) {
93  oStream_ << "PoleZero::tick(): channel and StkFrames arguments are incompatible!";
94  handleError( StkError::FUNCTION_ARGUMENT );
95  }
96 #endif
97 
98  StkFloat *samples = &frames[channel];
99  unsigned int hop = frames.channels();
100  for ( unsigned int i=0; i<frames.frames(); i++, samples += hop ) {
101  inputs_[0] = gain_ * *samples;
102  *samples = b_[0] * inputs_[0] + b_[1] * inputs_[1] - a_[1] * outputs_[1];
103  inputs_[1] = inputs_[0];
104  outputs_[1] = *samples;
105  }
106 
107  lastFrame_[0] = outputs_[1];
108  return frames;
109 }

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

The Synthesis ToolKit in C++ (STK)
©1995--2014 Perry R. Cook and Gary P. Scavone. All Rights Reserved.