Nsound::FilterBandPassVocoder Class Reference

#include <Nsound/FilterBandPassVocoder.h>

Inheritance diagram for Nsound::FilterBandPassVocoder:

Public Member Functions
	FilterBandPassVocoder (const float64 &sample_rate, const float64 &frequency_low, const float64 &frequency_high)
virtual	~FilterBandPassVocoder ()
AudioStream	filter (const AudioStream &x)
AudioStream	filter (const AudioStream &x, const Buffer &frequencies)
AudioStream	filter (const AudioStream &x, const Buffer &low_frequencies, const Buffer &high_frequencies)
Buffer	filter (const Buffer &x)
Buffer	filter (const Buffer &x, const Buffer &frequencies)
Buffer	filter (const Buffer &x, const Buffer &frequencies_Hz_low, const Buffer &frequencies_Hz_high)
virtual float64	filter (const float64 &x)
virtual float64	filter (const float64 &x, const float64 &frequency_Hz)
virtual float64	filter (const float64 &x, const float64 &frequency_Hz_low, const float64 &frequency_Hz_high)
void	plot (boolean show_fc=true, boolean show_phase=false)
void	reset ()
void	setRealtime (bool flag)
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 Member Functions
void	makeKernel (const float64 &f_low, const float64 &f_high)

Protected Attributes
float64	frequency_low_
float64	frequency_high_
float64	omega2_
float64	f_
float64	att_
float64	low1_
float64	low2_
float64	mid1_
float64	mid2_
float64	high1_
float64	high2_
float64	sample_rate_
float64	two_pi_over_sample_rate_
float64	sample_time_
uint32	kernel_size_
bool	is_realtime_

Private Member Functions
	FilterBandPassVocoder (const FilterBandPassVocoder &copy)
FilterBandPassVocoder &	operator= (const FilterBandPassVocoder &rhs)

Detailed Description

Definition at line 52 of file FilterBandPassVocoder.h.

Constructor & Destructor Documentation

FilterBandPassVocoder::FilterBandPassVocoder	(	const float64 &	sample_rate,
		const float64 &	frequency_low,
		const float64 &	frequency_high
	)

Definition at line 48 of file FilterBandPassVocoder.cc.

References reset().

    :
    Filter(sample_rate),
    frequency_low_(frequency_low),
    frequency_high_(frequency_high),
    omega2_(0.0),
    f_(0.0),
    att_(0.0),
    low1_(0.0),
    low2_(0.0),
    mid1_(0.0),
    mid2_(0.0),
    high1_(0.0),
    high2_(0.0)
{
    reset();
}

FilterBandPassVocoder::~FilterBandPassVocoder ( )

virtual

Definition at line 71 of file FilterBandPassVocoder.cc.

{
}

Nsound::FilterBandPassVocoder::FilterBandPassVocoder ( const FilterBandPassVocoder &  copy )

private

Member Function Documentation

AudioStream FilterBandPassVocoder::filter

(

const AudioStream &

x

)

Definition at line 77 of file FilterBandPassVocoder.cc.

References Nsound::Filter::filter().

Referenced by filter().

{
    return Filter::filter(x);
}

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

Definition at line 84 of file FilterBandPassVocoder.cc.

References Nsound::Filter::filter().

{
    return Filter::filter(x);
}

AudioStream FilterBandPassVocoder::filter	(	const AudioStream &	x,
		const Buffer &	low_frequencies,
		const Buffer &	high_frequencies
	)

Definition at line 91 of file FilterBandPassVocoder.cc.

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

{
    uint32 n_channels = x.getNChannels();

    AudioStream y(x.getSampleRate(), n_channels);

    for(uint32 channel = 0; channel < n_channels; ++channel)
    {
        y[channel] = FilterBandPassVocoder::filter(
            x[channel],
            frequencies_Hz_low,
            frequencies_Hz_high);
    }

    return y;
}

Buffer FilterBandPassVocoder::filter

(

const Buffer &

x

)

Definition at line 113 of file FilterBandPassVocoder.cc.

References Nsound::Filter::filter().

{
    return Filter::filter(x);
}

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

Definition at line 120 of file FilterBandPassVocoder.cc.

References Nsound::Filter::filter().

{
    return Filter::filter(x);
}

Buffer FilterBandPassVocoder::filter	(	const Buffer &	x,
		const Buffer &	frequencies_Hz_low,
		const Buffer &	frequencies_Hz_high
	)

Definition at line 127 of file FilterBandPassVocoder.cc.

References Nsound::Buffer::cbegin(), filter(), and Nsound::Buffer::getLength().

{
    Buffer::const_circular_iterator low  = frequencies_Hz_low.cbegin();
    Buffer::const_circular_iterator high = frequencies_Hz_high.cbegin();

    Buffer y;

    for(uint32 i = 0; i < x.getLength(); ++i, ++low, ++high)
    {
        y << FilterBandPassVocoder::filter(x[i], *low, *high);
    }

    return y;
}

float64 FilterBandPassVocoder::filter ( const float64 &  x )

virtual

Implements Nsound::Filter.

Definition at line 147 of file FilterBandPassVocoder.cc.

References att_, f_, high1_, high2_, low1_, low2_, mid1_, mid2_, and omega2_.

{
    high1_ = x - f_ * mid1_ - low1_;
    mid1_ += high1_ * omega2_;
    low1_ += mid1_;

    high2_ = low1_ - f_ * mid2_ - low2_;
    mid2_ += high2_ * omega2_;
    low2_ += mid2_;

    return high2_ * att_;
};

float64 FilterBandPassVocoder::filter ( const float64 &  x, const float64 &  frequency_Hz  )

virtual

Implements Nsound::Filter.

Definition at line 162 of file FilterBandPassVocoder.cc.

References filter().

{
    return FilterBandPassVocoder::filter(x);
}

float64 FilterBandPassVocoder::filter ( const float64 &  x, const float64 &  frequency_Hz_low, const float64 &  frequency_Hz_high  )

virtual

Definition at line 169 of file FilterBandPassVocoder.cc.

References filter(), and makeKernel().

{
    makeKernel(frequencies_Hz_low, frequencies_Hz_high);
    return FilterBandPassVocoder::filter(x);
}

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

Definition at line 180 of file FilterBandPassVocoder.cc.

References att_, Nsound::Plotter::axvline(), f_, frequency_high_, frequency_low_, omega2_, Nsound::Filter::plot(), Nsound::Plotter::subplot(), and Nsound::Plotter::title().

{
    char title[256];
    sprintf(title,
        "Band Pass IIR Frequency Response\n"
        "fl = %0.1f Hz, fh = %01f Hz, omega2 = %0.1f Hz, f_ = %0.1f Hz, att_ = %0.1f",
        frequency_low_,
        frequency_high_,
        omega2_,
        f_,
        att_);

    Filter::plot(show_phase);

    Plotter pylab;

    uint32 n_rows = 1;

    if(show_phase)
    {
        n_rows = 2;
    }

    if(show_fc)
    {
        pylab.subplot(n_rows, 1, 1);

        pylab.axvline(frequency_low_,"color='red'");
        pylab.axvline(frequency_high_,"color='red'");

        pylab.title(title);
    }
}

void FilterBandPassVocoder::reset ( )

virtual

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

Implements Nsound::Filter.

Definition at line 216 of file FilterBandPassVocoder.cc.

References frequency_high_, frequency_low_, high1_, high2_, low1_, low2_, makeKernel(), mid1_, and mid2_.

Referenced by FilterBandPassVocoder().

{
    low1_ =
    low2_ =
    mid1_ =
    mid2_ =
    high1_ =
    high2_ = 0.0;

    makeKernel(frequency_low_, frequency_high_);
}

void FilterBandPassVocoder::makeKernel ( const float64 &  f_low, const float64 &  f_high  )

protected

Definition at line 230 of file FilterBandPassVocoder.cc.

References att_, f_, M_PI, omega2_, and Nsound::Filter::sample_rate_.

Referenced by filter(), and reset().

{
    float64 fc = f_high - 0.5 * (f_high - f_low);

    float64 omega = fc * 2.0 * M_PI / sample_rate_;

    omega2_ = omega * omega;

    f_ = 0.4 / omega;

    att_ = 1.0 / (6.0 + ((std::exp(fc / sample_rate_) - 1.0) * 10.0));
}

FilterBandPassVocoder& Nsound::FilterBandPassVocoder::operator= ( const FilterBandPassVocoder &  rhs )

private

void Nsound::Filter::setRealtime ( bool  flag )

inlineinherited

Definition at line 57 of file Filter.h.

References Nsound::Filter::is_realtime_.

{is_realtime_ = flag;}

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

inherited

Definition at line 76 of file Filter.cc.

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

{
    if(!is_realtime_) reset();

    uint32 n_channels = x.getNChannels();

    if(is_realtime_ && n_channels > 1)
    {
        M_THROW("In real-time mode, a filter per audio channel must be used!");
    }

    AudioStream y(x.getSampleRate(), n_channels);

    for(uint32 channel = 0; channel < n_channels; ++channel)
    {
        y[channel] = filter(x[channel], frequency);
    }

    return y;
}

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

inherited

Definition at line 140 of file Filter.cc.

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

{
    if(!is_realtime_) reset();

    Buffer::const_iterator itor = x.begin();
    Buffer::const_iterator end = x.end();

    Buffer y(x.getLength());

    while(itor != end)
    {
        y << filter(*itor, frequency);

        ++itor;
    }

    return y;
}

Buffer Filter::getFrequencyAxis ( const uint32  n_fft = 8192 )

inherited

Definition at line 185 of file Filter.cc.

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

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

{
    uint32 fft_chunk_size = FFTransform::roundUp2(
        static_cast<int32>(n_fft));

    uint32 n_samples = fft_chunk_size / 2 + 1;

    float64 f_step = (1.0 / (static_cast<float64>(fft_chunk_size) / 2.0))
                   * (sample_rate_ / 2.0);

    Buffer f_axis;

    float64 f = 0.0;

    for(uint32 i = 0; i < n_samples; ++i)
    {
        f_axis << f;
        f += f_step;
    }

    return f_axis;
};

Buffer Filter::getFrequencyResponse ( const uint32  n_fft = 8192 )

inherited

Definition at line 210 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().

{
    FFTransform fft(sample_rate_);

//~    fft.setWindow(HANNING);

    FFTChunkVector vec;

    vec = fft.fft(getImpulseResponse(), n_fft);

    return vec[0].getMagnitude();
}

Buffer Filter::getImpulseResponse ( const uint32  n_samples = 8192 )

inherited

Definition at line 225 of file Filter.cc.

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

Referenced by Nsound::Filter::getFrequencyResponse(), Nsound::FilterHighPassFIR::getImpulseResponse(), Nsound::FilterLowPassFIR::getImpulseResponse(), Nsound::FilterLeastSquaresFIR::getImpulseResponse(), Nsound::FilterIIR::getImpulseResponse(), and Nsound::Filter::getPhaseResponse().

{
    if(!is_realtime_) reset();

    Buffer response(n_samples);

    response << filter(1.0);

    for(uint32 i = 1; i < n_samples; ++i)
    {
        response << filter(0.0);
    }

    if(!is_realtime_) reset();

    return response;
}

virtual uint32 Nsound::Filter::getKernelSize ( ) const

inlinevirtualinherited

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

Definition at line 96 of file Filter.h.

References Nsound::Filter::kernel_size_.

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

{return kernel_size_;};

Buffer Filter::getPhaseResponse ( )

inherited

Definition at line 245 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().

{
    uint32 n_samples = static_cast<uint32>(sample_rate_ * 2);

    FFTransform fft(n_samples);

    FFTChunkVector vec;

    vec = fft.fft(getImpulseResponse(), n_samples);

    Buffer phase = vec[0].getPhase();

    return phase.subbuffer(0, phase.getLength() / 2 + 1);
}

float64 Nsound::Filter::getSampleRate ( ) const

inlineinherited

Definition at line 102 of file Filter.h.

References Nsound::Filter::sample_rate_.

{ return sample_rate_; };

void Filter::plot ( boolean  show_phase = false )

inherited

Definition at line 262 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(), Nsound::FilterLowPassMoogVcf::plot(), Nsound::FilterPhaser::plot(), Nsound::FilterTone::plot(), Nsound::FilterHighPassIIR::plot(), Nsound::FilterCombLowPassFeedback::plot(), Nsound::FilterLowPassIIR::plot(), Nsound::FilterLowPassFIR::plot(), Nsound::FilterHighPassFIR::plot(), Nsound::FilterAllPass::plot(), plot(), Nsound::FilterBandPassFIR::plot(), Nsound::FilterLeastSquaresFIR::plot(), Nsound::FilterFlanger::plot(), Nsound::FilterBandRejectFIR::plot(), Nsound::FilterBandPassIIR::plot(), Nsound::FilterBandRejectIIR::plot(), and Nsound::FilterParametricEqualizer::plot().

{
    Buffer x = getFrequencyAxis();
    Buffer fr = getFrequencyResponse().getdB();

    Plotter pylab;

    pylab.figure();

    uint32 n_rows = 1;
    uint32 n_cols = 1;

    if(show_phase)
    {
        n_rows = 2;
    }

    pylab.subplot(n_rows, n_cols, 1);

    // Frequency response
    pylab.plot(x,fr, "blue");

    pylab.xlabel("Frequency (Hz)");
    pylab.ylabel("Frequency Response (dB)");

    // Phase response
    if(show_phase)
    {
        pylab.subplot(n_rows, n_cols, 2);

        Buffer pr = getPhaseResponse().getdB();

        pylab.plot(x,pr);

        pylab.xlabel("Frequency (Hz)");
        pylab.ylabel("Phase Response (dB)");
    }

    float64 ymax = fr.getMax();
    float64 height = ymax - -60.0;

    pylab.ylim(-60.0, ymax + 0.05 * height);
}

Member Data Documentation

float64 Nsound::FilterBandPassVocoder::frequency_low_

protected

Definition at line 115 of file FilterBandPassVocoder.h.

Referenced by plot(), and reset().

float64 Nsound::FilterBandPassVocoder::frequency_high_

protected

Definition at line 116 of file FilterBandPassVocoder.h.

Referenced by plot(), and reset().

float64 Nsound::FilterBandPassVocoder::omega2_

protected

Definition at line 117 of file FilterBandPassVocoder.h.

Referenced by filter(), makeKernel(), and plot().

float64 Nsound::FilterBandPassVocoder::f_

protected

Definition at line 118 of file FilterBandPassVocoder.h.

Referenced by filter(), makeKernel(), and plot().

float64 Nsound::FilterBandPassVocoder::att_

protected

Definition at line 119 of file FilterBandPassVocoder.h.

Referenced by filter(), makeKernel(), and plot().

float64 Nsound::FilterBandPassVocoder::low1_

protected

Definition at line 120 of file FilterBandPassVocoder.h.

Referenced by filter(), and reset().

float64 Nsound::FilterBandPassVocoder::low2_

protected

Definition at line 121 of file FilterBandPassVocoder.h.

Referenced by filter(), and reset().

float64 Nsound::FilterBandPassVocoder::mid1_

protected

Definition at line 122 of file FilterBandPassVocoder.h.

Referenced by filter(), and reset().

float64 Nsound::FilterBandPassVocoder::mid2_

protected

Definition at line 123 of file FilterBandPassVocoder.h.

Referenced by filter(), and reset().

float64 Nsound::FilterBandPassVocoder::high1_

protected

Definition at line 124 of file FilterBandPassVocoder.h.

Referenced by filter(), and reset().

float64 Nsound::FilterBandPassVocoder::high2_

protected

Definition at line 125 of file FilterBandPassVocoder.h.

Referenced by filter(), and reset().

float64 Nsound::Filter::sample_rate_

protectedinherited

Definition at line 113 of file Filter.h.

Referenced by Nsound::FilterPhaser::filter(), Nsound::FilterCombLowPassFeedback::filter(), Nsound::FilterDelay::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::FilterHighPassFIR::makeKernel(), Nsound::FilterStageIIR::makeKernel(), makeKernel(), Nsound::FilterLeastSquaresFIR::makeKernel(), Nsound::FilterParametricEqualizer::makeKernel(), Nsound::FilterPhaser::operator=(), Nsound::FilterLeastSquaresFIR::operator=(), Nsound::FilterFlanger::operator=(), Nsound::FilterIIR::operator=(), Nsound::FilterLowPassMoogVcf::plot(), Nsound::FilterPhaser::plot(), Nsound::FilterTone::plot(), Nsound::FilterHighPassIIR::plot(), Nsound::FilterLowPassIIR::plot(), Nsound::FilterCombLowPassFeedback::plot(), Nsound::FilterLowPassFIR::plot(), Nsound::FilterHighPassFIR::plot(), Nsound::FilterAllPass::plot(), Nsound::FilterBandPassFIR::plot(), Nsound::FilterLeastSquaresFIR::plot(), Nsound::FilterFlanger::plot(), Nsound::FilterBandRejectFIR::plot(), Nsound::FilterBandRejectIIR::plot(), Nsound::FilterBandPassIIR::plot(), Nsound::FilterParametricEqualizer::plot(), Nsound::FilterLowPassIIR::setCutoff(), and Nsound::FilterLeastSquaresFIR::setWindow().

float64 Nsound::Filter::two_pi_over_sample_rate_

protectedinherited

Definition at line 114 of file Filter.h.

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

float64 Nsound::Filter::sample_time_

protectedinherited

Definition at line 115 of file Filter.h.

Referenced by Nsound::FilterLowPassMoogVcf::_make_filter().

uint32 Nsound::Filter::kernel_size_

protectedinherited

Definition at line 116 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::FilterHighPassFIR::makeKernel(), Nsound::FilterLowPassFIR::makeKernel(), Nsound::FilterBandRejectFIR::makeKernel(), Nsound::FilterLeastSquaresFIR::makeKernel(), Nsound::FilterLeastSquaresFIR::operator=(), Nsound::FilterLowPassFIR::plot(), Nsound::FilterHighPassFIR::plot(), Nsound::FilterLeastSquaresFIR::plot(), Nsound::FilterBandRejectFIR::plot(), Nsound::FilterLowPassFIR::reset(), Nsound::FilterHighPassFIR::reset(), Nsound::FilterLeastSquaresFIR::reset(), Nsound::FilterLeastSquaresFIR::setKernel(), Nsound::FilterLeastSquaresFIR::setWindow(), and Nsound::FilterHighPassFIR::spectraReversal_().

bool Nsound::Filter::is_realtime_

protectedinherited

Definition at line 118 of file Filter.h.

Referenced by Nsound::Filter::filter(), Nsound::FilterBandRejectIIR::filter(), Nsound::FilterBandRejectFIR::filter(), Nsound::Filter::getImpulseResponse(), and Nsound::Filter::setRealtime().

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

• Nsound/FilterBandPassVocoder.h
• Nsound/FilterBandPassVocoder.cc