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Tighten incoming data, Add FM UpSampler

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Geoffrey Merck 2020-05-12 22:06:26 +02:00
parent 2cc6c1f68f
commit 994226e4b1
6 changed files with 169 additions and 37 deletions
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FMUpSampler.cpp Normal file
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/*
* Copyright (C) 2020 by Jonathan Naylor G4KLX
* Copyright (C) 2020 by Geoffrey Merck F4FXL - KC3FRA
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "FMUpSampler.h"
const uint32_t FM_UPSAMPLE_MASK = 0x00000FFFU;
CFMUpSampler::CFMUpSampler(uint16_t length) :
m_upSampleIndex(0),
m_pack({0U, 0U, 0U}),
m_samples(length)
{
}
void CFMUpSampler::reset()
{
m_upSampleIndex = 0U;
m_pack = {0U, 0U, 0U};
m_samples.reset();
}
void CFMUpSampler::addData(const uint8_t* data, uint16_t length)
{
for(uint16_t i = 0U; i < length; i++) {
switch (m_upSampleIndex)
{
case 0U:
m_pack.byte0 = data[i];
break;
case 1U:
m_pack.byte1 = data[i];
break;
case 2U: {
m_pack.byte2 = data[i];
uint32_t pack = 0U;
uint8_t* packPtr = (uint8_t*)&pack;
packPtr[1] = m_pack.byte0;
packPtr[2] = m_pack.byte1;
packPtr[3] = m_pack.byte2;
q15_t sample2 = q15_t(uint16_t(pack & FM_UPSAMPLE_MASK) - 2048);
q15_t sample1 = q15_t(uint16_t(pack >> 12) - 2048);
m_samples.put(sample1);
m_samples.put(0);
m_samples.put(0);
m_samples.put(sample2);
m_samples.put(0);
m_samples.put(0);
}
break;
default:
//shoudl never happen
break;
}
m_upSampleIndex ++;
if (m_upSampleIndex > 2U)
m_upSampleIndex = 0U;
}
}
bool CFMUpSampler::getSample(q15_t& sample)
{
return m_samples.get(sample);
}
uint16_t CFMUpSampler::getSpace() const
{
return m_samples.getSpace();
}