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Clean up and better names for variables

This commit is contained in:
Geoffrey Merck 2020-01-29 19:57:12 +01:00
parent 0a06b26748
commit fe700f253b
2 changed files with 28 additions and 30 deletions
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46
ambed/cagc.cpp
View File

@ -36,23 +36,21 @@
CAGC::CAGC(float initialLeveldB)
{
// set internal gain appropriately
m_g = pow(10.0f, initialLeveldB/20.0f);
m_Gain = pow(10.0f, initialLeveldB/20.0f);
//+- 10dB Margin, TODO Move margin to constant
m_GainMax = pow(10.0f, (initialLeveldB + 10.0f)/20.0f);
m_GainMin = pow(10.0f, (initialLeveldB - 10.0f)/20.0f);
m_EnergyPrime = 1.0f;
m_targetEnergy = 32768.0f;//TODO : Move to parameter ?
// ensure resulting gain is not arbitrarily low
if (m_g < 1e-16f)
m_g = 1e-16f;
m_scale = 32768.0f;
m_bandwidth = 1e-2f; //TODO : Move to parameter ?
m_gMax = pow(10.0f, (initialLeveldB + 10.0f)/20.0f);//+- 10dB Margin, TODO Move margin to constant
m_gMin = pow(10.0f, (initialLeveldB - 10.0f)/20.0f);
m_alpha = m_bandwidth;
m_y2_prime = 1.0f;
m_Bandwidth = 1e-2f;//TODO : Move to parameter ?
m_Alpha = m_Bandwidth;
}
float CAGC::GetGain()
{
return 20.0f*log10(m_g);
return 20.0f*log10(m_Gain);
}
void CAGC::Apply(uint8 * voice, int size)
@ -60,30 +58,30 @@ void CAGC::Apply(uint8 * voice, int size)
for (int i = 0; i < size; i+=2)
{
//Get the sample
float _x = (float)(short)MAKEWORD(voice[i+1], voice[i]);
float input = (float)(short)MAKEWORD(voice[i+1], voice[i]);
//apply AGC
// apply gain to input sample
float _y = _x * m_g;
float output = input * m_Gain;
// compute output signal energy
float y2 = (_y * _y) / m_scale;
float instantEnergy = (output * output) / m_targetEnergy;
// smooth energy estimate using single-pole low-pass filter
m_y2_prime = (1.0f - m_alpha) * m_y2_prime + m_alpha*y2;
m_EnergyPrime = (1.0f - m_Alpha) * m_EnergyPrime + m_Alpha * instantEnergy;
// update gain according to output energy
if (m_y2_prime > 1e-6f)
m_g *= exp( -0.5f * m_alpha * log(m_y2_prime) );
if (m_EnergyPrime > 1e-6f)
m_Gain *= exp( -0.5f * m_Alpha * log(m_EnergyPrime) );
// clamp gain
if (m_g > m_gMax)
m_g = m_gMax;
else if(m_g < m_gMin)
m_g = m_gMin;
if (m_Gain > m_GainMax)
m_Gain = m_GainMax;
else if(m_Gain < m_GainMin)
m_Gain = m_GainMin;
//write processed sample back
voice[i] = HIBYTE((short)_y);
voice[i+1] = LOBYTE((short)_y);
voice[i] = HIBYTE((short)output);
voice[i+1] = LOBYTE((short)output);
}
}

12
ambed/cagc.h
View File

@ -41,16 +41,16 @@ public:
float GetGain();//gets current gain
private:
float m_g; // current gain value
float m_gMax, m_gMin; //gain clamping
float m_scale; // scale value for target energy
float m_Gain; // current gain value
float m_GainMax, m_GainMin; //gain clamping
float m_targetEnergy; // scale value for target energy
// gain control loop filter parameters
float m_bandwidth; // bandwidth-time constant
float m_alpha; // feed-back gain
float m_Bandwidth; // bandwidth-time constant
float m_Alpha; // feed-back gain
// signal level estimate
float m_y2_prime; // filtered output signal energy estimate
float m_EnergyPrime; // filtered output signal energy estimate
};
#endif /* cgc_h */