mirror of
https://github.com/DSheirer/sdrtrunk.git
synced 2026-11-12 16:47:31 -05:00
[WIP] Polyphase channelizer experiments
This commit is contained in:
Denny
223
src/dsp/filter/channelizer/PolyphaseChannelizer.java
Normal file
223
src/dsp/filter/channelizer/PolyphaseChannelizer.java
Normal file
@@ -0,0 +1,223 @@
|
||||
/*******************************************************************************
|
||||
* sdrtrunk
|
||||
* Copyright (C) 2014-2017 Dennis Sheirer
|
||||
*
|
||||
* This program is free software: you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License as published by
|
||||
* the Free Software Foundation, either version 3 of the License, or
|
||||
* (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program. If not, see <http://www.gnu.org/licenses/>
|
||||
*
|
||||
******************************************************************************/
|
||||
package dsp.filter.channelizer;
|
||||
|
||||
import dsp.filter.design.FilterDesignException;
|
||||
import dsp.filter.fir.FIRFilterSpecification;
|
||||
import dsp.filter.fir.real.RealFIRFilter;
|
||||
import dsp.filter.fir.remez.RemezFIRFilterDesigner;
|
||||
import dsp.mixer.Oscillator;
|
||||
import org.jtransforms.fft.FloatFFT_1D;
|
||||
import org.slf4j.Logger;
|
||||
import org.slf4j.LoggerFactory;
|
||||
import sample.complex.ComplexBuffer;
|
||||
|
||||
import java.text.DecimalFormat;
|
||||
|
||||
public class PolyphaseChannelizer
|
||||
{
|
||||
private final static Logger mLog = LoggerFactory.getLogger(PolyphaseChannelizer.class);
|
||||
|
||||
private RealFIRFilter[] mFilters;
|
||||
private int mFilterPointer = 0;
|
||||
private int mChannelCount;
|
||||
private int mBlockSize;
|
||||
private float[] mFilteredSamples;
|
||||
private boolean mToggle = false;
|
||||
private FloatFFT_1D mFFT;
|
||||
|
||||
private DecimalFormat DECIMAL_FORMAT = new DecimalFormat("0.0000");
|
||||
|
||||
/**
|
||||
* Creates a polyphase filter bank that divides the input frequency band into evenly spaced channels that
|
||||
* are oversampled by 2x for output.
|
||||
*
|
||||
* @param taps of a low-pass filter designed for the inbound sample rate with a cutoff frequency
|
||||
* equal to the channel bandwidth (sample rate / filters). If you need to synthesize (combine two or more
|
||||
* filte outputs) a new bandwidth signal from the outputs of this filter, then the filter should be designed
|
||||
* as a nyquist filter with -6 dB attenuation at the channel bandwidth cutoff frequency
|
||||
*
|
||||
* @param channels - number of filters/channels to output. Since this filter bank oversamples each filter
|
||||
* output, this number must be even (divisible by the oversample rate).
|
||||
*/
|
||||
public PolyphaseChannelizer(float[] taps, int channels)
|
||||
{
|
||||
assert(channels % 2 == 0);
|
||||
|
||||
mChannelCount = channels;
|
||||
|
||||
initFilters(taps);
|
||||
}
|
||||
|
||||
public void filter(float inphase, float quadrature)
|
||||
{
|
||||
int iIndex = 2 * mFilterPointer;
|
||||
int qIndex = iIndex + 1;
|
||||
|
||||
mFilteredSamples[iIndex] = mFilters[iIndex].filter(inphase);
|
||||
mFilteredSamples[qIndex] = mFilters[qIndex].filter(quadrature);
|
||||
|
||||
if(mFilterPointer == 0)
|
||||
{
|
||||
calculate();
|
||||
mFilterPointer = mChannelCount - 1;
|
||||
mToggle = !mToggle;
|
||||
}
|
||||
else if(mFilterPointer == mBlockSize)
|
||||
{
|
||||
calculate();
|
||||
mFilterPointer--;
|
||||
}
|
||||
else
|
||||
{
|
||||
mFilterPointer--;
|
||||
}
|
||||
}
|
||||
|
||||
public void filter(ComplexBuffer buffer)
|
||||
{
|
||||
float[] samples = buffer.getSamples();
|
||||
|
||||
for(int x = 0; x < samples.length; x += 2)
|
||||
{
|
||||
filter(samples[x], samples[x + 1]);
|
||||
}
|
||||
}
|
||||
|
||||
private void calculate()
|
||||
{
|
||||
float[] samples = new float[mFilters.length];
|
||||
|
||||
if(mToggle)
|
||||
{
|
||||
System.arraycopy(mFilteredSamples, 0, samples, mChannelCount, mChannelCount);
|
||||
System.arraycopy(mFilteredSamples, mChannelCount, samples, 0, mChannelCount);
|
||||
}
|
||||
else
|
||||
{
|
||||
System.arraycopy(mFilteredSamples, 0, samples, 0, mFilteredSamples.length);
|
||||
}
|
||||
|
||||
//FFT is executed in-place where the output overwrites the input
|
||||
mFFT.complexInverse(samples, true);
|
||||
|
||||
dispatch(samples);
|
||||
}
|
||||
|
||||
private void dispatch(float[] channels)
|
||||
{
|
||||
StringBuilder sb = new StringBuilder();
|
||||
|
||||
for(int x = 0; x < channels.length; x += 2)
|
||||
{
|
||||
sb.append((x/2)).append("-")
|
||||
.append(DECIMAL_FORMAT.format(magnitude(channels[x], channels[x + 1], mChannelCount))).append(" ");
|
||||
}
|
||||
|
||||
mLog.debug("Out: " + sb.toString());
|
||||
}
|
||||
|
||||
private double magnitude(float real, float imaginary, int fftSize)
|
||||
{
|
||||
return Math.sqrt(Math.pow(real, 2.0) + Math.pow(imaginary, 2.0));
|
||||
}
|
||||
|
||||
/**
|
||||
* Distributes the filter taps to each of the polyphase filters
|
||||
*
|
||||
* @param taps
|
||||
*/
|
||||
private void initFilters(float[] taps)
|
||||
{
|
||||
int tapCount = (int)Math.ceil((double)taps.length / (double)mChannelCount);
|
||||
|
||||
float[][] coefficients = new float[mChannelCount][tapCount];
|
||||
|
||||
for(int filter = 0; filter < mChannelCount; filter++)
|
||||
{
|
||||
for(int tap = 0; tap < tapCount; tap++)
|
||||
{
|
||||
int index = filter * mChannelCount + tap;
|
||||
|
||||
if(index < taps.length)
|
||||
{
|
||||
coefficients[filter][tap] = taps[index];
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
mFilters = new RealFIRFilter[mChannelCount * 2];
|
||||
|
||||
for(int filter = 0; filter < mChannelCount; filter++)
|
||||
{
|
||||
//Inphase filter
|
||||
mFilters[2 * filter] = new RealFIRFilter(coefficients[filter], 1.0f);
|
||||
|
||||
//Quadrature filter
|
||||
mFilters[2 * filter + 1] = new RealFIRFilter(coefficients[filter], 1.0f);
|
||||
}
|
||||
|
||||
mFilteredSamples = new float[mFilters.length];
|
||||
mFFT = new FloatFFT_1D(mChannelCount);
|
||||
mBlockSize = mChannelCount / 2;
|
||||
mFilterPointer = mChannelCount -1;
|
||||
}
|
||||
|
||||
public static void main(String[] args)
|
||||
{
|
||||
mLog.debug("Starting ...");
|
||||
|
||||
FIRFilterSpecification specification = FIRFilterSpecification.lowPassBuilder()
|
||||
.sampleRate(4000)
|
||||
.gridDensity(16)
|
||||
.passBandCutoff(950)
|
||||
.passBandAmplitude(1.0)
|
||||
.passBandRipple(0.01)
|
||||
.stopBandStart(1050)
|
||||
.stopBandAmplitude(0.0)
|
||||
.stopBandRipple(0.005)
|
||||
.build();
|
||||
|
||||
RemezFIRFilterDesigner filterDesigner = new RemezFIRFilterDesigner(specification);
|
||||
|
||||
if(filterDesigner.isValid())
|
||||
{
|
||||
try
|
||||
{
|
||||
float[] taps = filterDesigner.getImpulseResponse();
|
||||
|
||||
PolyphaseChannelizer channelizer = new PolyphaseChannelizer(taps, 8);
|
||||
|
||||
Oscillator oscillator = new Oscillator(-1000, 8000);
|
||||
|
||||
for(int x = 0; x < 2000; x++)
|
||||
{
|
||||
channelizer.filter(oscillator.getComplex().inphase(), oscillator.getComplex().quadrature());
|
||||
oscillator.rotate();
|
||||
}
|
||||
}
|
||||
catch(FilterDesignException fde)
|
||||
{
|
||||
mLog.error("Couldn't design filter to specification");
|
||||
}
|
||||
}
|
||||
|
||||
mLog.debug("Finished!");
|
||||
}
|
||||
}
|
||||
@@ -1,65 +1,64 @@
|
||||
package dsp.filter.design;
|
||||
|
||||
import org.slf4j.Logger;
|
||||
import org.slf4j.LoggerFactory;
|
||||
|
||||
import dsp.filter.fir.FIRFilterSpecification;
|
||||
import dsp.filter.fir.remez.RemezFIRFilterDesigner;
|
||||
import javafx.application.Application;
|
||||
import javafx.scene.Scene;
|
||||
import javafx.stage.Stage;
|
||||
import org.slf4j.Logger;
|
||||
import org.slf4j.LoggerFactory;
|
||||
|
||||
public class FilterViewer extends Application
|
||||
{
|
||||
private final static Logger mLog = LoggerFactory.getLogger( FilterViewer.class );
|
||||
private final static Logger mLog = LoggerFactory.getLogger(FilterViewer.class);
|
||||
|
||||
/**
|
||||
* Developer tool to visualize filter designs
|
||||
*/
|
||||
public FilterViewer()
|
||||
{
|
||||
}
|
||||
|
||||
@Override
|
||||
public void start( Stage primaryStage ) throws Exception
|
||||
{
|
||||
Scene scene = new Scene( new FilterView( getFilter() ) );
|
||||
|
||||
primaryStage.setTitle( "Filter Viewer" );
|
||||
primaryStage.setScene( scene );
|
||||
primaryStage.show();
|
||||
}
|
||||
|
||||
public static void main( String[] args )
|
||||
{
|
||||
launch( args );
|
||||
}
|
||||
/**
|
||||
* Developer tool to visualize filter designs
|
||||
*/
|
||||
public FilterViewer()
|
||||
{
|
||||
}
|
||||
|
||||
/**
|
||||
* Provides the filter to visualize. Modify this method to visualize your filter design.
|
||||
*/
|
||||
private float[] getFilter()
|
||||
{
|
||||
// FIRFilterSpecification specification = FIRFilterSpecification.lowPassBuilder()
|
||||
// .sampleRate( 48000 )
|
||||
// .gridDensity( 16 )
|
||||
// .passBandCutoff( 3200 )
|
||||
// .passBandAmplitude( 1.0 )
|
||||
// .passBandRipple( 0.02 )
|
||||
// .stopBandStart( 4000 )
|
||||
@Override
|
||||
public void start(Stage primaryStage) throws Exception
|
||||
{
|
||||
Scene scene = new Scene(new FilterView(getFilter()));
|
||||
|
||||
primaryStage.setTitle("Filter Viewer");
|
||||
primaryStage.setScene(scene);
|
||||
primaryStage.show();
|
||||
}
|
||||
|
||||
public static void main(String[] args)
|
||||
{
|
||||
launch(args);
|
||||
}
|
||||
|
||||
/**
|
||||
* Provides the filter to visualize. Modify this method to visualize your filter design.
|
||||
*/
|
||||
private float[] getFilter()
|
||||
{
|
||||
FIRFilterSpecification specification = FIRFilterSpecification.lowPassBuilder()
|
||||
.sampleRate(4000)
|
||||
.gridDensity(16)
|
||||
.passBandCutoff(950)
|
||||
.passBandAmplitude(1.0)
|
||||
.passBandRipple(0.01)
|
||||
.stopBandStart(1050)
|
||||
.stopBandAmplitude(0.0)
|
||||
.stopBandRipple(0.005)
|
||||
.build();
|
||||
|
||||
// FIRFilterSpecification specification = FIRFilterSpecification.highPassBuilder()
|
||||
// .sampleRate( 24000 )
|
||||
// .stopBandCutoff( 800 )
|
||||
// .stopBandAmplitude( 0.0 )
|
||||
// .stopBandRipple( 0.03 )
|
||||
// .passBandStart( 1000 )
|
||||
// .passBandAmplitude( 1.0 )
|
||||
// .passBandRipple( 0.08 )
|
||||
// .build();
|
||||
|
||||
FIRFilterSpecification specification = FIRFilterSpecification.highPassBuilder()
|
||||
.sampleRate( 24000 )
|
||||
.stopBandCutoff( 800 )
|
||||
.stopBandAmplitude( 0.0 )
|
||||
.stopBandRipple( 0.03 )
|
||||
.passBandStart( 1000 )
|
||||
.passBandAmplitude( 1.0 )
|
||||
.passBandRipple( 0.08 )
|
||||
.build();
|
||||
|
||||
// FIRFilterSpecification specification = FIRFilterSpecification.bandPassBuilder()
|
||||
// .sampleRate( 48000 )
|
||||
@@ -71,24 +70,24 @@ public class FilterViewer extends Application
|
||||
// .passRipple( 0.008)
|
||||
// .build();
|
||||
|
||||
float[] taps = null;
|
||||
float[] taps = null;
|
||||
|
||||
// taps = FilterFactory.getLowPass( 16000, 2400, 73, WindowType.HANNING );
|
||||
|
||||
try
|
||||
{
|
||||
RemezFIRFilterDesigner designer = new RemezFIRFilterDesigner( specification );
|
||||
|
||||
if( designer.isValid() )
|
||||
{
|
||||
taps = designer.getImpulseResponse();
|
||||
}
|
||||
}
|
||||
catch( FilterDesignException fde )
|
||||
{
|
||||
mLog.error( "Filter design error", fde );
|
||||
}
|
||||
|
||||
return taps;
|
||||
}
|
||||
try
|
||||
{
|
||||
RemezFIRFilterDesigner designer = new RemezFIRFilterDesigner(specification);
|
||||
|
||||
if(designer.isValid())
|
||||
{
|
||||
taps = designer.getImpulseResponse();
|
||||
}
|
||||
}
|
||||
catch(FilterDesignException fde)
|
||||
{
|
||||
mLog.error("Filter design error", fde);
|
||||
}
|
||||
|
||||
return taps;
|
||||
}
|
||||
}
|
||||
|
||||
Reference in New Issue
Block a user