Nsound::FilterTone Class Reference

#include <Nsound/FilterTone.h>

Inheritance diagram for Nsound::FilterTone:
Inheritance graph
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List of all members.

Classes

struct  Kernel
 A class to store calculated kernels. More...

Public Member Functions

 FilterTone (const float64 &sample_rate, const float64 &half_power_frequency)
virtual ~FilterTone ()
AudioStream filter (const AudioStream &x)
AudioStream filter (const AudioStream &x, const Buffer &hp_frequencies)
Buffer filter (const Buffer &x)
Buffer filter (const Buffer &x, const Buffer &hp_frequencies)
float64 filter (const float64 &x)
float64 filter (const float64 &x, const float64 &hp_frequency)
float64 getFrequency () const
uint32 getKernelSize () const
void plot (boolean show_fc=true, boolean show_phase=false)
void reset ()
void makeKernel (const float64 &half_power_frequency)
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)
Buffer getPhaseResponse ()
float64 getSampleRate () const
void plot (boolean show_phase=false)

Protected Types

typedef std::set< Kernel > KernelCache

Protected Attributes

float64 hp_frequency_
float64 b_
float64 a_
float64 last_output_
KernelCache kernel_cache_
float64 sample_rate_
float64 two_pi_over_sample_rate_
uint32 kernel_size_

Detailed Description

Definition at line 47 of file FilterTone.h.

Member Typedef Documentation

typedef std::set<Kernel> Nsound::FilterTone::KernelCache [protected]

Definition at line 127 of file FilterTone.h.

Constructor & Destructor Documentation

FilterTone::FilterTone ( const float64 &  sample_rate,
const float64 &  half_power_frequency 
)

Definition at line 42 of file FilterTone.cc.

References reset().

00044     :
00045     Filter(sample_rate),
00046     hp_frequency_(half_power_frequency),
00047     b_(0.0),
00048     a_(0.0),
00049     last_output_(0.0),
00050     kernel_cache_()
00051 {
00052     reset();
}

FilterTone::~FilterTone (  )  [virtual]

Definition at line 56 of file FilterTone.cc.

00057 {
00058 
00059 }

Member Function Documentation

AudioStream FilterTone::filter ( const AudioStream &  x  ) 

Reimplemented from Nsound::Filter.

Definition at line 64 of file FilterTone.cc.

Referenced by filter(), Nsound::Pluck::generate(), Nsound::GuitarBass::play(), and Nsound::FluteSlide::play().

00065 {
00066     return Filter::filter(x);
00067 }

AudioStream FilterTone::filter ( const AudioStream &  x,
const Buffer &  hp_frequencies 
)

Reimplemented from Nsound::Filter.

Definition at line 72 of file FilterTone.cc.

References filter().

00073 {
00074     return Filter::filter(x, hp_frequencies);
00075 }

Buffer FilterTone::filter ( const Buffer &  x  ) 

Reimplemented from Nsound::Filter.

Definition at line 80 of file FilterTone.cc.

References filter().

00081 {
00082     return Filter::filter(x);
00083 }

Buffer FilterTone::filter ( const Buffer &  x,
const Buffer &  hp_frequencies 
)

Reimplemented from Nsound::Filter.

Definition at line 88 of file FilterTone.cc.

References filter().

00089 {
00090     return Filter::filter(x, hp_frequencies);
00091 }

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

Implements Nsound::Filter.

Definition at line 96 of file FilterTone.cc.

References a_, b_, and last_output_.

00097 {
00098     float64 y = b_ * x - a_ * last_output_;
00099 
00100     last_output_ = y;
00101 
00102     return y;
00103 }

float64 FilterTone::filter ( const float64 &  x,
const float64 &  hp_frequency 
) [virtual]

Implements Nsound::Filter.

Definition at line 108 of file FilterTone.cc.

References filter(), and makeKernel().

00109 {
00110     makeKernel(hp_frequency);
00111 
00112     return FilterTone::filter(x);
00113 }

float64 Nsound::FilterTone::getFrequency (  )  const [inline]

Definition at line 86 of file FilterTone.h.

References hp_frequency_.

00086 {return hp_frequency_;};

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

Reimplemented from Nsound::Filter.

Definition at line 90 of file FilterTone.h.

00090 { return 2; };

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

Definition at line 150 of file FilterTone.cc.

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

00151 {
00152     char title[128];
00153     sprintf(title,
00154         "Tone Filter Frequency Response\n"
00155         "order = %d, fc = %0.1f Hz, sr = %0.1f Hz",
00156         2, hp_frequency_, sample_rate_);
00157 
00158     Filter::plot(show_phase);
00159 
00160     Plotter pylab;
00161 
00162     int32 topplot = 111;
00163 
00164     if(show_phase)
00165     {
00166         topplot = 211;
00167     }
00168 
00169     if(show_fc)
00170     {
00171         pylab.subplot(topplot);
00172 
00173         pylab.axvline(hp_frequency_,"color='red'");
00174 
00175         pylab.title(title);
00176     }
00177 
00178 }

void FilterTone::reset (  )  [virtual]

Resets interal history buffer and sets the cut off frequency to the one used at declaration.

Implements Nsound::Filter.

Definition at line 183 of file FilterTone.cc.

References hp_frequency_, last_output_, and makeKernel().

Referenced by FilterTone().

00184 {
00185     last_output_ = 0.0;
00186     makeKernel(hp_frequency_);
00187 }

void FilterTone::makeKernel ( const float64 &  half_power_frequency  ) 

Definition at line 118 of file FilterTone.cc.

References a_, b_, kernel_cache_, and Nsound::Filter::two_pi_over_sample_rate_.

Referenced by filter(), and reset().

00119 {
00120     FilterTone::
00121     Kernel new_kernel(static_cast<uint32>(half_power_frequency * 10));
00122 
00123     // See if the kernel is in the cache.
00124     KernelCache::const_iterator itor = kernel_cache_.find(new_kernel);
00125 
00126     if(itor != kernel_cache_.end())
00127     {
00128         // The kernel was found in the cache.
00129         b_ = itor->b_;
00130         a_ = itor->a_;
00131         return;
00132     }
00133 
00134     // The filter wasn't in the cache, need to make it.
00135 
00136     float64 temp = 2.0 - ::cos(two_pi_over_sample_rate_ * half_power_frequency);
00137 
00138     a_ = -1.0 * (temp - ::sqrt(temp * temp - 1.0));
00139     b_ = 1.0 + a_;
00140 
00141     new_kernel.b_ = b_;
00142     new_kernel.a_ = a_;
00143 
00144     kernel_cache_.insert(new_kernel);
00145 }

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 }

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

float64 Nsound::FilterTone::hp_frequency_ [protected]

Definition at line 109 of file FilterTone.h.

Referenced by getFrequency(), plot(), and reset().

float64 Nsound::FilterTone::b_ [protected]

Definition at line 110 of file FilterTone.h.

Referenced by filter(), and makeKernel().

float64 Nsound::FilterTone::a_ [protected]

Definition at line 111 of file FilterTone.h.

Referenced by filter(), and makeKernel().

float64 Nsound::FilterTone::last_output_ [protected]

Definition at line 112 of file FilterTone.h.

Referenced by filter(), and reset().

KernelCache Nsound::FilterTone::kernel_cache_ [protected]

Definition at line 129 of file FilterTone.h.

Referenced by makeKernel().

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

Definition at line 131 of file Filter.h.

Referenced by Nsound::FilterPhaser::filter(), Nsound::FilterDelay::filter(), Nsound::FilterCombLowPassFeedback::filter(), Nsound::FilterAllPass::FilterAllPass(), Nsound::FilterCombLowPassFeedback::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=(), 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(), Nsound::FilterCombLowPassFeedback::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 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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