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SSB demod: AGC threshold step up/down optimization

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This commit is contained in:
f4exb 2017-07-26 16:23:34 +02:00
parent 432ab7d834
commit e17a815125
2 changed files with 41 additions and 25 deletions
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64
sdrbase/dsp/agc.cpp
View File

@ -9,7 +9,7 @@
#include "dsp/agc.h"
#include "util/smootherstep.h"
#define StepLengthMax 4800 // 100ms
#define StepLengthMax 2400 // 50ms
AGC::AGC(int historySize, Real R) :
m_u0(1.0),
@ -51,6 +51,7 @@ MagSquaredAGC::MagSquaredAGC(int historySize, double R, double threshold) :
m_threshold(threshold),
m_gate(0),
m_stepLength(std::min(StepLengthMax, historySize/2)),
m_stepDelta(1.0/m_stepLength),
m_stepUpCounter(0),
m_stepDownCounter(m_stepLength),
m_gateCounter(0)
@ -62,15 +63,15 @@ MagSquaredAGC::~MagSquaredAGC()
void MagSquaredAGC::resize(int historySize, Real R)
{
m_stepLength = std::min(StepLengthMax, historySize/2);
m_stepDelta = 1.0 / m_stepLength;
m_stepUpCounter = 0;
m_stepDownCounter = m_stepLength;
AGC::resize(historySize, R);
}
void MagSquaredAGC::feed(Complex& ci)
{
m_magsq = ci.real()*ci.real() + ci.imag()*ci.imag();
m_moving_average.feed(m_magsq);
m_u0 = m_R / m_moving_average.average();
ci *= m_u0;
ci *= feedAndGetValue(ci);
}
double MagSquaredAGC::feedAndGetValue(const Complex& ci)
@ -103,24 +104,30 @@ double MagSquaredAGC::feedAndGetValue(const Complex& ci)
{
m_stepDownCounter = m_stepLength;
if (m_stepUpCounter < m_stepLength) {
if (m_stepUpCounter < m_stepLength)
{
m_stepUpCounter++;
return m_u0 * StepFunctions::smootherstep(m_stepUpCounter * m_stepDelta);
}
else
{
return m_u0;
}
return m_u0 * StepFunctions::smootherstep( ((float) m_stepUpCounter) / ((float) m_stepLength) );
}
else
{
m_stepUpCounter = 0;
if (m_stepDownCounter > 0) {
if (m_stepDownCounter > 0)
{
m_stepDownCounter--;
return m_u0 * StepFunctions::smootherstep(m_stepDownCounter * m_stepDelta);
}
else
{
return 0.0;
}
return m_u0 * StepFunctions::smootherstep( ((float) m_stepDownCounter) / ((float) m_stepLength) );
}
//return (m_count < m_moving_average.historySize()) ? m_u0 : 0.0;
}
//MagAGC::MagAGC() :
@ -134,6 +141,7 @@ MagAGC::MagAGC(int historySize, double R, double threshold) :
m_threshold(threshold),
m_gate(0),
m_stepLength(std::min(StepLengthMax, historySize/2)),
m_stepDelta(1.0/m_stepLength),
m_stepUpCounter(0),
m_stepDownCounter(m_stepLength),
m_gateCounter(0)
@ -145,15 +153,15 @@ MagAGC::~MagAGC()
void MagAGC::resize(int historySize, Real R)
{
m_stepLength = std::min(StepLengthMax, historySize/2);
m_stepDelta = 1.0 / m_stepLength;
m_stepUpCounter = 0;
m_stepDownCounter = m_stepLength;
AGC::resize(historySize, R);
}
void MagAGC::feed(Complex& ci)
{
m_magsq = ci.real()*ci.real() + ci.imag()*ci.imag();
m_moving_average.feed(m_magsq);
m_u0 = m_R / sqrt(m_moving_average.average());
ci *= m_u0;
ci *= feedAndGetValue(ci);
}
double MagAGC::feedAndGetValue(const Complex& ci)
@ -186,24 +194,30 @@ double MagAGC::feedAndGetValue(const Complex& ci)
{
m_stepDownCounter = m_stepLength;
if (m_stepUpCounter < m_stepLength) {
if (m_stepUpCounter < m_stepLength)
{
m_stepUpCounter++;
return m_u0 * StepFunctions::smootherstep(m_stepUpCounter * m_stepDelta);
}
else
{
return m_u0;
}
return m_u0 * StepFunctions::smootherstep( ((float) m_stepUpCounter) / ((float) m_stepLength) );
}
else
{
m_stepUpCounter = 0;
if (m_stepDownCounter > 0) {
if (m_stepDownCounter > 0)
{
m_stepDownCounter--;
return m_u0 * StepFunctions::smootherstep(m_stepDownCounter * m_stepDelta);
}
else
{
return 0.0;
}
return m_u0 * StepFunctions::smootherstep( ((float) m_stepDownCounter) / ((float) m_stepLength) );
}
//return (m_count < m_moving_average.historySize()) ? m_u0 : 0.0;
}
//AlphaAGC::AlphaAGC() :

2
sdrbase/dsp/agc.h
View File

@ -45,6 +45,7 @@ private:
double m_threshold; //!< squelch on magsq average
int m_gate; //!< power threshold gate in number of samples
int m_stepLength; //!< transition step length in number of samples
double m_stepDelta; //!< transition step unit by sample
int m_stepUpCounter; //!< step up transition samples counter
int m_stepDownCounter; //!< step down transition samples counter
int m_gateCounter; //!< threshold gate samples counter
@ -66,6 +67,7 @@ private:
double m_threshold; //!< squelch on magsq average
int m_gate; //!< power threshold gate in number of samples
int m_stepLength; //!< transition step length in number of samples
double m_stepDelta; //!< transition step unit by sample
int m_stepUpCounter; //!< step up transition samples counter
int m_stepDownCounter; //!< step down transition samples counter
int m_gateCounter; //!< threshold gate samples counter