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SDRdaemon plugin: better calculation of write - read pointers delta. Better amortization of buffer R/W compensation with an alpha factor of 0.25

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f4exb
2016-03-20 02:49:25 +01:00
parent bfdcac70d0
commit 0ffc02102e
2 changed files with 9 additions and 8 deletions
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plugins/samplesource/sdrdaemon/sdrdaemonbuffer.cpp
+7 -6
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@@ -19,6 +19,7 @@
#include <QDebug>
#include <cassert>
#include <cstring>
#include <cmath>
#include <lz4.h>
@@ -264,28 +265,28 @@ uint8_t *SDRdaemonBuffer::readData(int32_t length)
if ((m_nbReads > 5*m_rawBufferLengthSeconds) && m_autoCorrBuffer)
{
int32_t dBytes;
int32_t dI = (m_rawSize / 2) - m_readIndex; // delta of read index to the middle of buffer (positive)
if (m_readIndex > m_writeIndex) { // write leads
dBytes = m_writeIndex; // positive from start of buffer
dBytes = m_writeIndex + dI; // positive from start of buffer + delta read index
} else { // read leads
dBytes = m_writeIndex - (int32_t) m_rawSize; // negative from end of buffer
dBytes = m_writeIndex - (int32_t) m_rawSize + dI; // negative from end of buffer minus delta read index
}
m_balCorrection += dBytes / (int32_t) (m_nbReads * m_iqSampleSize); // correction is in number of samples
int32_t corrLimit = (int32_t) m_rawSize / (int32_t) (10 * m_rawBufferLengthSeconds * m_iqSampleSize);
m_balCorrection = (m_balCorrection / 4) + ((int32_t) dBytes / (int32_t) (m_nbReads * m_iqSampleSize)); // correction is in number of samples. Alpha = 0.25
if (m_balCorrection < -m_balCorrLimit) {
m_balCorrection = -m_balCorrLimit;
} else if (m_balCorrection > m_balCorrLimit) {
m_balCorrection = m_balCorrLimit;
}
m_nbReads = 0;
}
else
{
m_balCorrection = 0;
}
m_nbReads = 0;
// un-arm
m_skewTest = false;
}