Nsound::FilterCombLowPassFeedback Class Reference

#include <Nsound/FilterCombLowPassFeedback.h>

Inheritance diagram for Nsound::FilterCombLowPassFeedback:
Inheritance graph
[legend]

List of all members.

Public Member Functions

 FilterCombLowPassFeedback (const float64 &sample_rate, const float64 &delay_time_seconds, const float64 &feedback_gain, const float64 &low_pass_frequency_Hz)
 FilterCombLowPassFeedback (const FilterCombLowPassFeedback &copy)
virtual ~FilterCombLowPassFeedback ()
AudioStream filter (const AudioStream &x)
AudioStream filter (const AudioStream &x, const Buffer &frequencies)
Buffer filter (const Buffer &x)
Buffer filter (const Buffer &x, const Buffer &frequencies)
float64 filter (const float64 &x)
float64 filter (const float64 &x, const float64 &frequency)
FilterCombLowPassFeedback & operator= (const FilterCombLowPassFeedback &rhs)
void plot (boolean show_fc=true, boolean show_phase=false)
void reset ()
AudioStream filter (const AudioStream &x, const float64 &frequency)
Buffer filter (const Buffer &x, const float64 &frequency)
Buffer getFrequencyAxis (const uint32 n_fft=8192)
Buffer getFrequencyResponse (const uint32 n_fft=8192)
Buffer getImpulseResponse (const uint32 n_samples=8192)
virtual uint32 getKernelSize () const
Buffer getPhaseResponse ()
float64 getSampleRate () const
void plot (boolean show_phase=false)

Protected Attributes

FilterDelay * delay_
float64 feedback_gain_
float64 damp1_
float64 damp2_
float64 y_history_
float64 sample_rate_
float64 two_pi_over_sample_rate_
uint32 kernel_size_

Detailed Description

A class for filtering audio in the frequecy domain.

Definition at line 48 of file FilterCombLowPassFeedback.h.

Constructor & Destructor Documentation

FilterCombLowPassFeedback::FilterCombLowPassFeedback ( const float64 &  sample_rate,
const float64 &  delay_time_seconds,
const float64 &  feedback_gain,
const float64 &  low_pass_frequency_Hz 
)

Definition at line 48 of file FilterCombLowPassFeedback.cc.

References damp1_, damp2_, delay_, feedback_gain_, reset(), and Nsound::Filter::sample_rate_.

00054     :
00055     Filter(sample_rate),
00056     delay_(NULL),
00057     feedback_gain_(feedback_gain),
00058     damp1_(0.0),
00059     damp2_(0.0),
00060     y_history_(0.0)
00061 {
00062     delay_ = new FilterDelay(sample_rate_, delay_time_seconds);
00063 
00064     FilterCombLowPassFeedback::reset();
00065 
00066     if(feedback_gain_ < 0.0)
00067     {
00068         feedback_gain_ = 0.0;
00069     }
00070 
00071     if(feedback_gain_ >= 1.0)
00072     {
00073         feedback_gain_ = 0.999999;
00074     }
00075 
00076     damp1_ = low_pass_frequency_Hz / sample_rate_;
00077 
00078     if(damp1_ > 0.5)
00079     {
00080         damp1_ = 0.5;
00081     }
00082 
00083     damp2_ = 1.0 - damp1_;
}

FilterCombLowPassFeedback::FilterCombLowPassFeedback ( const FilterCombLowPassFeedback &  copy  ) 

Definition at line 87 of file FilterCombLowPassFeedback.cc.

00089     :
00090     Filter(copy.sample_rate_),
00091     delay_(new FilterDelay(*copy.delay_)),
00092     feedback_gain_(copy.feedback_gain_),
00093     damp1_(copy.damp1_),
00094     damp2_(copy.damp2_),
00095     y_history_(y_history_)
00096 {
}

FilterCombLowPassFeedback::~FilterCombLowPassFeedback (  )  [virtual]

Definition at line 101 of file FilterCombLowPassFeedback.cc.

References delay_.

00102 {
00103     delete delay_;
00104 }

Member Function Documentation

AudioStream FilterCombLowPassFeedback::filter ( const AudioStream &  x  ) 

Reimplemented from Nsound::Filter.

Definition at line 109 of file FilterCombLowPassFeedback.cc.

References reset().

Referenced by Nsound::ReverberationRoom::filter(), filter(), and FilterCombLowPassFeedback_UnitTest().

00110 {
00111     FilterCombLowPassFeedback::reset();
00112     return Filter::filter(x);
00113 }

AudioStream FilterCombLowPassFeedback::filter ( const AudioStream &  x,
const Buffer &  frequencies 
)

Reimplemented from Nsound::Filter.

Definition at line 118 of file FilterCombLowPassFeedback.cc.

References filter(), and reset().

00119 {
00120     FilterCombLowPassFeedback::reset();
00121     return Filter::filter(x, frequencies);
00122 }

Buffer FilterCombLowPassFeedback::filter ( const Buffer &  x  ) 

Reimplemented from Nsound::Filter.

Definition at line 127 of file FilterCombLowPassFeedback.cc.

References filter(), and reset().

00128 {
00129     FilterCombLowPassFeedback::reset();
00130     return Filter::filter(x);
00131 }

Buffer FilterCombLowPassFeedback::filter ( const Buffer &  x,
const Buffer &  frequencies 
)

Reimplemented from Nsound::Filter.

Definition at line 136 of file FilterCombLowPassFeedback.cc.

References filter(), and reset().

00137 {
00138     FilterCombLowPassFeedback::reset();
00139     return Filter::filter(x, frequencies);
00140 }

float64 FilterCombLowPassFeedback::filter ( const float64 &  x  )  [virtual]

Implements Nsound::Filter.

Definition at line 145 of file FilterCombLowPassFeedback.cc.

References damp1_, damp2_, delay_, feedback_gain_, Nsound::FilterDelay::filter(), and y_history_.

00146 {
00147     float64 d = delay_->filter(x + y_history_ * feedback_gain_);
00148 
00149     y_history_ = d * damp2_ + y_history_ * damp1_;
00150 
00151     return d;
00152 }

float64 FilterCombLowPassFeedback::filter ( const float64 &  x,
const float64 &  frequency 
) [virtual]

Implements Nsound::Filter.

Definition at line 157 of file FilterCombLowPassFeedback.cc.

References damp1_, damp2_, filter(), and Nsound::Filter::sample_rate_.

00158 {
00159     damp1_ = frequency_Hz / sample_rate_;
00160 
00161     if(damp1_ > 0.5)
00162     {
00163         damp1_ = 0.5;
00164     }
00165 
00166     damp2_ = 1.0 - damp1_;
00167 
00168     return FilterCombLowPassFeedback::filter(x);
00169 }

FilterCombLowPassFeedback & FilterCombLowPassFeedback::operator= ( const FilterCombLowPassFeedback &  rhs  ) 

Definition at line 174 of file FilterCombLowPassFeedback.cc.

References damp1_, damp2_, delay_, feedback_gain_, and y_history_.

00175 {
00176     *delay_ = *rhs.delay_;
00177     feedback_gain_ = rhs.feedback_gain_;
00178     damp1_ = rhs.damp1_;
00179     damp2_ = rhs.damp2_;
00180     y_history_ = rhs.y_history_;
00181 
00182     return *this;
00183 }

void FilterCombLowPassFeedback::plot ( boolean  show_fc = true,
boolean  show_phase = false 
)

Definition at line 188 of file FilterCombLowPassFeedback.cc.

References Nsound::Plotter::axvline(), damp1_, Nsound::Filter::sample_rate_, Nsound::Plotter::subplot(), and Nsound::Plotter::title().

00189 {
00190     char title[128];
00191     sprintf(title,
00192         "Comb Low Pass Feedback Frequency Response\n"
00193         "order = %d, fc = %0.1f Hz, sr = %0.1f Hz",
00194         2,
00195         damp1_ * sample_rate_,
00196         sample_rate_);
00197 
00198     Filter::plot(show_phase);
00199 
00200     Plotter pylab;
00201 
00202     int32 topplot = 111;
00203 
00204     if(show_phase)
00205     {
00206         topplot = 211;
00207     }
00208 
00209     if(show_fc)
00210     {
00211         pylab.subplot(topplot);
00212 
00213         pylab.axvline(damp1_ * sample_rate_,"color='red'");
00214 
00215         pylab.title(title);
00216     }
00217 }

void FilterCombLowPassFeedback::reset (  )  [virtual]

Implements Nsound::Filter.

Definition at line 222 of file FilterCombLowPassFeedback.cc.

References delay_, Nsound::FilterDelay::reset(), and y_history_.

Referenced by filter(), FilterCombLowPassFeedback(), and Nsound::ReverberationRoom::reset().

00223 {
00224     delay_->reset();
00225     y_history_ = 0.0;
00226 }

AudioStream Filter::filter ( const AudioStream &  x,
const float64 &  frequency 
) [inherited]

Reimplemented in Nsound::FilterAllPass, Nsound::FilterBandPassIIR, Nsound::FilterBandRejectIIR, Nsound::FilterDelay, Nsound::FilterFlanger, Nsound::FilterHighPassFIR, Nsound::FilterHighPassIIR, Nsound::FilterLeastSquaresFIR, Nsound::FilterLowPassFIR, Nsound::FilterLowPassIIR, and Nsound::FilterStageIIR.

Definition at line 72 of file Filter.cc.

References Nsound::Filter::filter(), Nsound::AudioStream::getNChannels(), Nsound::AudioStream::getSampleRate(), and Nsound::Filter::reset().

00073 {
00074     reset();
00075 
00076     uint32 n_channels = x.getNChannels();
00077 
00078     AudioStream y(x.getSampleRate(), n_channels);
00079 
00080     for(uint32 channel = 0; channel < n_channels; ++channel)
00081     {
00082         y[channel] = filter(x[channel], frequency);
00083     }
00084 
00085     return y;
00086 }

Buffer Filter::filter ( const Buffer &  x,
const float64 &  frequency 
) [inherited]

Reimplemented in Nsound::FilterAllPass, Nsound::FilterBandPassIIR, Nsound::FilterBandRejectIIR, Nsound::FilterDelay, Nsound::FilterFlanger, Nsound::FilterHighPassFIR, Nsound::FilterHighPassIIR, Nsound::FilterLeastSquaresFIR, Nsound::FilterLowPassFIR, Nsound::FilterLowPassIIR, and Nsound::FilterStageIIR.

Definition at line 129 of file Filter.cc.

References Nsound::Buffer::begin(), Nsound::Buffer::end(), Nsound::Filter::filter(), Nsound::Buffer::getLength(), and Nsound::Filter::reset().

00130 {
00131     reset();
00132 
00133     Buffer::const_iterator itor = x.begin();
00134     Buffer::const_iterator end = x.end();
00135 
00136     Buffer y(x.getLength());
00137 
00138     while(itor != end)
00139     {
00140         y << filter(*itor, frequency);
00141 
00142         ++itor;
00143     }
00144 
00145     return y;
00146 }

Buffer Filter::getFrequencyAxis ( const uint32  n_fft = 8192  )  [inherited]

Definition at line 176 of file Filter.cc.

References Nsound::FFTransform::roundUp2(), and Nsound::Filter::sample_rate_.

Referenced by main(), Nsound::Filter::plot(), and Nsound::FilterIIR::savePlot().

00177 {
00178     uint32 fft_chunk_size = FFTransform::roundUp2(
00179         static_cast<int32>(n_fft));
00180 
00181     uint32 n_samples = fft_chunk_size / 2 + 1;
00182 
00183     float64 f_step = (1.0 / (static_cast<float64>(fft_chunk_size) / 2.0))
00184                    * (sample_rate_ / 2.0);
00185 
00186     Buffer f_axis;
00187 
00188     float64 f = 0.0;
00189 
00190     for(uint32 i = 0; i < n_samples; ++i)
00191     {
00192         f_axis << f;
00193         f += f_step;
00194     }
00195 
00196     return f_axis;
00197 };

Buffer Filter::getFrequencyResponse ( const uint32  n_fft = 8192  )  [inherited]

Definition at line 202 of file Filter.cc.

References Nsound::FFTransform::fft(), Nsound::Filter::getImpulseResponse(), and Nsound::Filter::sample_rate_.

Referenced by Nsound::FilterBandPassIIR::FilterBandPassIIR(), FilterLeastSquaresFIR_UnitTest(), Nsound::FilterIIR::getRMS(), main(), Nsound::Filter::plot(), and Nsound::FilterIIR::savePlot().

00203 {
00204     FFTransform fft(sample_rate_);
00205 
00206 //~    fft.setWindow(HANNING);
00207 
00208     FFTChunkVector vec;
00209 
00210     vec = fft.fft(getImpulseResponse(), n_fft);
00211 
00212     return vec[0].getMagnitude();
00213 }

Buffer Filter::getImpulseResponse ( const uint32  n_samples = 8192  )  [inherited]

Reimplemented in Nsound::FilterIIR.

Definition at line 218 of file Filter.cc.

References Nsound::Filter::filter(), and Nsound::Filter::reset().

Referenced by Nsound::Filter::getFrequencyResponse(), and Nsound::Filter::getPhaseResponse().

00219 {
00220     reset();
00221 
00222     Buffer response(n_samples);
00223 
00224     response << filter(1.0);
00225 
00226     for(uint32 i = 1; i < n_samples; ++i)
00227     {
00228         response << filter(0.0);
00229     }
00230 
00231     reset();
00232 
00233     return response;
00234 }

virtual uint32 Nsound::Filter::getKernelSize (  )  const [inline, virtual, inherited]

Reimplemented in Nsound::FilterIIR, and Nsound::FilterTone.

Definition at line 109 of file Filter.h.

References Nsound::Filter::kernel_size_.

Referenced by Nsound::FilterBandPassIIR::FilterBandPassIIR(), Nsound::FilterBandRejectIIR::plot(), Nsound::FilterBandPassIIR::plot(), and Nsound::FilterBandPassFIR::plot().

00109 {return kernel_size_;};

Buffer Filter::getPhaseResponse (  )  [inherited]

Definition at line 239 of file Filter.cc.

References Nsound::FFTransform::fft(), Nsound::Filter::getImpulseResponse(), Nsound::Buffer::getLength(), Nsound::Filter::sample_rate_, and Nsound::Buffer::subbuffer().

Referenced by Nsound::Filter::plot().

00240 {
00241     uint32 n_samples = static_cast<uint32>(sample_rate_ * 2);
00242 
00243     FFTransform fft(n_samples);
00244 
00245     FFTChunkVector vec;
00246 
00247     vec = fft.fft(getImpulseResponse(), n_samples);
00248 
00249     Buffer phase = vec[0].getPhase();
00250 
00251     return phase.subbuffer(0, phase.getLength() / 2 + 1);
00252 }

float64 Nsound::Filter::getSampleRate (  )  const [inline, inherited]

Definition at line 117 of file Filter.h.

References Nsound::Filter::sample_rate_.

00117 { return sample_rate_; };

void Filter::plot ( boolean  show_phase = false  )  [inherited]

Definition at line 257 of file Filter.cc.

References Nsound::Plotter::figure(), Nsound::Buffer::getdB(), Nsound::Filter::getFrequencyAxis(), Nsound::Filter::getFrequencyResponse(), Nsound::Buffer::getMax(), Nsound::Filter::getPhaseResponse(), Nsound::Plotter::plot(), Nsound::Plotter::subplot(), Nsound::Plotter::xlabel(), Nsound::Plotter::ylabel(), and Nsound::Plotter::ylim().

Referenced by main().

00258 {
00259     Buffer x = getFrequencyAxis();
00260     Buffer fr = getFrequencyResponse().getdB();
00261 
00262     Plotter pylab;
00263 
00264     pylab.figure();
00265 
00266     int subplot_int = 111;
00267 
00268     if(show_phase)
00269     {
00270         subplot_int = 211;
00271     }
00272 
00273     pylab.subplot(subplot_int);
00274 
00275     // Frequency response
00276     pylab.plot(x,fr, "blue");
00277 
00278     pylab.xlabel("Frequency (Hz)");
00279     pylab.ylabel("Frequency Response (dB)");
00280 
00281     // Phase response
00282     if(show_phase)
00283     {
00284         pylab.subplot(subplot_int + 1);
00285 
00286         Buffer pr = getPhaseResponse().getdB();
00287 
00288         pylab.plot(x,pr);
00289 
00290         pylab.xlabel("Frequency (Hz)");
00291         pylab.ylabel("Phase Response (dB)");
00292     }
00293 
00294     float64 ymax = fr.getMax();
00295     float64 height = ymax - -60.0;
00296 
00297     pylab.ylim(-60.0, ymax + 0.05 * height);
00298 
00299 }

Member Data Documentation

FilterDelay* Nsound::FilterCombLowPassFeedback::delay_ [protected]

Definition at line 106 of file FilterCombLowPassFeedback.h.

Referenced by filter(), FilterCombLowPassFeedback(), operator=(), reset(), and ~FilterCombLowPassFeedback().

float64 Nsound::FilterCombLowPassFeedback::feedback_gain_ [protected]

Definition at line 108 of file FilterCombLowPassFeedback.h.

Referenced by filter(), FilterCombLowPassFeedback(), and operator=().

float64 Nsound::FilterCombLowPassFeedback::damp1_ [protected]

Definition at line 110 of file FilterCombLowPassFeedback.h.

Referenced by filter(), FilterCombLowPassFeedback(), operator=(), and plot().

float64 Nsound::FilterCombLowPassFeedback::damp2_ [protected]

Definition at line 111 of file FilterCombLowPassFeedback.h.

Referenced by filter(), FilterCombLowPassFeedback(), and operator=().

float64 Nsound::FilterCombLowPassFeedback::y_history_ [protected]

Definition at line 113 of file FilterCombLowPassFeedback.h.

Referenced by filter(), operator=(), and reset().

float64 Nsound::Filter::sample_rate_ [protected, inherited]

Definition at line 131 of file Filter.h.

Referenced by Nsound::FilterPhaser::filter(), Nsound::FilterDelay::filter(), filter(), Nsound::FilterAllPass::FilterAllPass(), FilterCombLowPassFeedback(), Nsound::FilterDelay::FilterDelay(), Nsound::FilterFlanger::FilterFlanger(), Nsound::FilterPhaser::FilterPhaser(), Nsound::FilterSlinky::FilterSlinky(), Nsound::Filter::getFrequencyAxis(), Nsound::Filter::getFrequencyResponse(), Nsound::Filter::getPhaseResponse(), Nsound::Filter::getSampleRate(), Nsound::FilterStageIIR::makeIIRKernelHelper(), Nsound::FilterStageIIR::makeKernel(), Nsound::FilterParametricEqualizer::makeKernel(), Nsound::FilterLeastSquaresFIR::makeKernel(), Nsound::FilterHighPassFIR::makeKernel(), Nsound::FilterBandPassVocoder::makeKernel(), Nsound::FilterPhaser::operator=(), Nsound::FilterLeastSquaresFIR::operator=(), Nsound::FilterIIR::operator=(), Nsound::FilterFlanger::operator=(), Nsound::FilterTone::plot(), Nsound::FilterPhaser::plot(), Nsound::FilterParametricEqualizer::plot(), Nsound::FilterLowPassIIR::plot(), Nsound::FilterLowPassFIR::plot(), Nsound::FilterLeastSquaresFIR::plot(), Nsound::FilterHighPassIIR::plot(), Nsound::FilterHighPassFIR::plot(), Nsound::FilterFlanger::plot(), plot(), Nsound::FilterBandRejectIIR::plot(), Nsound::FilterBandRejectFIR::plot(), Nsound::FilterBandPassIIR::plot(), Nsound::FilterBandPassFIR::plot(), Nsound::FilterAllPass::plot(), Nsound::FilterLowPassIIR::setCutoff(), and Nsound::FilterLeastSquaresFIR::setWindow().

float64 Nsound::Filter::two_pi_over_sample_rate_ [protected, inherited]

Definition at line 132 of file Filter.h.

Referenced by Nsound::FilterTone::makeKernel(), Nsound::FilterParametricEqualizer::makeKernel(), and Nsound::FilterLowPassFIR::makeKernel().

uint32 Nsound::Filter::kernel_size_ [protected, inherited]

Definition at line 133 of file Filter.h.

Referenced by Nsound::FilterLowPassFIR::filter(), Nsound::FilterLeastSquaresFIR::filter(), Nsound::FilterBandPassFIR::FilterBandPassFIR(), Nsound::FilterBandPassIIR::FilterBandPassIIR(), Nsound::FilterBandRejectIIR::FilterBandRejectIIR(), Nsound::FilterHighPassIIR::FilterHighPassIIR(), Nsound::FilterLeastSquaresFIR::FilterLeastSquaresFIR(), Nsound::FilterLowPassFIR::FilterLowPassFIR(), Nsound::FilterLowPassIIR::FilterLowPassIIR(), Nsound::FilterLeastSquaresFIR::getKernel(), Nsound::Filter::getKernelSize(), Nsound::FilterLowPassFIR::makeKernel(), Nsound::FilterLeastSquaresFIR::makeKernel(), Nsound::FilterHighPassFIR::makeKernel(), Nsound::FilterBandRejectFIR::makeKernel(), Nsound::FilterLeastSquaresFIR::operator=(), Nsound::FilterLowPassFIR::plot(), Nsound::FilterLeastSquaresFIR::plot(), Nsound::FilterHighPassFIR::plot(), Nsound::FilterBandRejectFIR::plot(), Nsound::FilterLowPassFIR::reset(), Nsound::FilterLeastSquaresFIR::reset(), Nsound::FilterHighPassFIR::reset(), Nsound::FilterLeastSquaresFIR::setKernel(), Nsound::FilterLeastSquaresFIR::setWindow(), and Nsound::FilterHighPassFIR::spectraReversal_().

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