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##2544 bladeRF supports up to 122 MHz sample rate. Adds new 2048 and 4096 half band decimation filters. (#2545)

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Co-authored-by: denny <dennis.sheirer@gmail.com>
This commit is contained in:
Denny Sheirer
2026-11-01 04:24:22 -05:00
committed by GitHub
parent 276f4a316a
commit 866aadc8c3
11 changed files with 660 additions and 31 deletions
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10
src/main/java/io/github/dsheirer/dsp/filter/decimate/DecimationFilterFactory.java
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@@ -29,12 +29,14 @@ import org.slf4j.LoggerFactory;
public class DecimationFilterFactory
{
private static final Logger mLog = LoggerFactory.getLogger(DecimationFilterFactory.class);
private static final int[] SUPPORTED_RATES = new int[]{1,2,4,8,16,32,64,128,256,512,1024};
public static final int MAXIMUM_DECIMATION_RATE = 4096;
private static final int[] SUPPORTED_RATES = new int[]{1,2,4,8,16,32,64,128,256,512,1024,2048,MAXIMUM_DECIMATION_RATE};
/**
* Creates a real-valued decimation filter for float array sample buffers providing approximately 70 dB of
* attenuation for out of band signal aliases, when the signal bandwidth is no more than half of the decimated
* sample rate. Supports power of 2 decimation rates up to 1024.
* sample rate. Supports power of 2 decimation rates up to 4096. Sample buffers must be an integer multiple of the
* decimation rate.
*
* @param decimationRate requested @see SUPPORTED_RATES
* @return constructed decimation filter
@@ -66,6 +68,10 @@ public class DecimationFilterFactory
return new RealDecimateX512Filter();
case 1024:
return new RealDecimateX1024Filter();
case 2048:
return new RealDecimateX2048Filter();
case 4096:
return new RealDecimateX4096Filter();
default:
throw new IllegalArgumentException("Unsupported decimation rate: " + decimationRate +
". Supported decimation rates are:" + Arrays.toString(SUPPORTED_RATES));

54
src/main/java/io/github/dsheirer/dsp/filter/decimate/RealDecimateX2048Filter.java Normal file
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@@ -0,0 +1,54 @@
/*
* *****************************************************************************
* Copyright (C) 2014-2026 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 io.github.dsheirer.dsp.filter.decimate;
import io.github.dsheirer.dsp.filter.FilterFactory;
import io.github.dsheirer.dsp.window.WindowType;
/**
* Decimate by 2048 filter for real valued sample buffers.
*/
public class RealDecimateX2048Filter extends RealDecimateX1024Filter
{
private static final int VALIDATION_LENGTH = 2048;
private static final int DECIMATE_BY_2048_FILTER_LENGTH = 11;
private static final WindowType DECIMATE_BY_2048_WINDOW_TYPE = WindowType.BLACKMAN;
private IRealDecimationFilter mFilter;
private float[] mOutput;
/**
* Constructs the decimation filter.
*/
public RealDecimateX2048Filter()
{
mFilter = FilterFactory.getRealDecimationFilter(DECIMATE_BY_2048_FILTER_LENGTH,
DECIMATE_BY_2048_WINDOW_TYPE);
}
@Override
public float[] decimateReal(float[] samples)
{
validate(samples, VALIDATION_LENGTH);
//Decimate by this filter, then by the parent decimation filter
mOutput = getIntermediateOutput(mOutput, samples.length / 2);
return super.decimateReal(mFilter.decimateReal(samples, mOutput));
}
}

54
src/main/java/io/github/dsheirer/dsp/filter/decimate/RealDecimateX4096Filter.java Normal file
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@@ -0,0 +1,54 @@
/*
* *****************************************************************************
* Copyright (C) 2014-2026 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 io.github.dsheirer.dsp.filter.decimate;
import io.github.dsheirer.dsp.filter.FilterFactory;
import io.github.dsheirer.dsp.window.WindowType;
/**
* Decimate by 4096 filter for real valued sample buffers.
*/
public class RealDecimateX4096Filter extends RealDecimateX2048Filter
{
private static final int VALIDATION_LENGTH = 4096;
private static final int DECIMATE_BY_4096_FILTER_LENGTH = 11;
private static final WindowType DECIMATE_BY_4096_WINDOW_TYPE = WindowType.BLACKMAN;
private IRealDecimationFilter mFilter;
private float[] mOutput;
/**
* Constructs the decimation filter.
*/
public RealDecimateX4096Filter()
{
mFilter = FilterFactory.getRealDecimationFilter(DECIMATE_BY_4096_FILTER_LENGTH,
DECIMATE_BY_4096_WINDOW_TYPE);
}
@Override
public float[] decimateReal(float[] samples)
{
validate(samples, VALIDATION_LENGTH);
//Decimate by this filter, then by the parent decimation filter
mOutput = getIntermediateOutput(mOutput, samples.length / 2);
return super.decimateReal(mFilter.decimateReal(samples, mOutput));
}
}