diff --git a/ambed/cagc.cpp b/ambed/cagc.cpp
new file mode 100644
index 0000000..880323d
--- /dev/null
+++ b/ambed/cagc.cpp
@@ -0,0 +1,94 @@
+//
+// cagc.cpp
+// ambed
+//
+// Created by Jean-Luc Deltombe (LX3JL) on 28/04/2017.
+// Copyright © 2015 Jean-Luc Deltombe (LX3JL). All rights reserved.
+//
+// ----------------------------------------------------------------------------
+// This file is part of ambed.
+//
+// xlxd 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.
+//
+// xlxd 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 Foobar. If not, see .
+// ----------------------------------------------------------------------------
+// Geoffrey Merck F4FXL / KC3FRA AGC code borrowed from Liquid DSP
+// Only took the parts we need qnd recoeded it to be close the XLX coding style
+// https://github.com/jgaeddert/liquid-dsp/blob/master/src/agc/src/agc.c
+
+#include
+#include "cagc.h"
+#include "main.h"
+
+////////////////////////////////////////////////////////////////////////////////////////
+// constructor
+
+CAGC::CAGC(float initialLeveldB)
+{
+ // set internal gain appropriately
+ m_Gain = pow(10.0f, initialLeveldB/20.0f);
+ //+- 10dB Margin, TODO Move margin to constant
+ m_GainMax = pow(10.0f, (initialLeveldB + AGC_CLAMPING)/20.0f);
+ m_GainMin = pow(10.0f, (initialLeveldB - AGC_CLAMPING)/20.0f);
+
+ m_EnergyPrime = 1.0f;
+
+ // We do not target full scale to avoid stauration
+ m_targetEnergy = 32767.0f * pow(10.0f, (initialLeveldB - 25.0)/20.0f);//25 dB below saturation as stated in docs
+ //we also substract our target gain
+
+ //this is the time constant of our AGC...
+ m_Bandwidth = 1e-2f;//TODO : Move to parameter ?
+ m_Alpha = m_Bandwidth;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////
+// get
+
+float CAGC::GetGain()
+{
+ return 20.0f*log10(m_Gain);
+}
+
+////////////////////////////////////////////////////////////////////////////////////////
+// process
+
+inline void CAGC::ProcessSampleBlock(uint8* voice, int length)
+{
+ for(int i = 0; i < length; i += 2)
+ {
+ float input = (float)(short)MAKEWORD(voice[i+1], voice[i]);
+ //apply AGC
+ // apply gain to input sample
+ float output = input * m_Gain;
+
+ // compute output signal energy, scaled to 0 to 1
+ float instantEnergy = abs(output) / m_targetEnergy;
+
+ // smooth energy estimate using single-pole low-pass filter
+ m_EnergyPrime = (1.0f - m_Alpha) * m_EnergyPrime + m_Alpha * instantEnergy;
+
+ // update gain according to output energy
+ if (m_EnergyPrime > 1e-6f)
+ m_Gain *= exp( -0.5f * m_Alpha * log(m_EnergyPrime) );
+
+ // clamp gain
+ 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)output);
+ voice[i+1] = LOBYTE((short)output);
+ }
+}
diff --git a/ambed/cagc.h b/ambed/cagc.h
new file mode 100644
index 0000000..f0ebf75
--- /dev/null
+++ b/ambed/cagc.h
@@ -0,0 +1,56 @@
+//
+// cagc.h
+// ambed
+//
+// Created by Jean-Luc Deltombe (LX3JL) on 26/04/2017.
+// Copyright © 2015 Jean-Luc Deltombe (LX3JL). All rights reserved.
+//
+// ----------------------------------------------------------------------------
+// This file is part of ambed.
+//
+// xlxd 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.
+//
+// xlxd 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 Foobar. If not, see .
+// ----------------------------------------------------------------------------
+// Geoffrey Merck F4FXL / KC3FRA AGC code largely inspired by Liquid DSP
+// Only took the parts we need qnd recoeded it to be close the XLX coding style
+// https://github.com/jgaeddert/liquid-dsp/blob/master/src/agc/src/agc.c
+
+#ifndef cagc_h
+#define cagc_h
+
+#include "csampleblockprocessor.h"
+
+class CAGC : CSampleBlockProcessor
+{
+public:
+ //Constructor
+ CAGC(float initialLeveldB);
+
+ //methods
+ void ProcessSampleBlock(uint8* voice, int length) ;
+ float GetGain();//gets current gain
+
+private:
+ 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
+
+ // signal level estimate
+ float m_EnergyPrime; // filtered output signal energy estimate
+};
+
+#endif /* cgc_h */
\ No newline at end of file
diff --git a/ambed/cfirfilter.cpp b/ambed/cfirfilter.cpp
new file mode 100644
index 0000000..67a0fb1
--- /dev/null
+++ b/ambed/cfirfilter.cpp
@@ -0,0 +1,75 @@
+//
+// cfirfilter.cpp
+// ambed
+//
+// Created by Jean-Luc Deltombe (LX3JL) on 26/04/2017.
+// Copyright © 2015 Jean-Luc Deltombe (LX3JL). All rights reserved.
+//
+// ----------------------------------------------------------------------------
+// This file is part of ambed.
+//
+// xlxd 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.
+//
+// xlxd 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 Foobar. If not, see .
+// ----------------------------------------------------------------------------
+// FIRFilter by Geoffrey Merck F4FXL / KC3FRA
+
+#include "cfirfilter.h"
+#include
+
+CFIRFilter::CFIRFilter(const float* taps, int tapsLength)
+{
+ m_taps = new float[tapsLength];
+ m_buffer = new float[tapsLength];
+ m_tapsLength = tapsLength;
+
+ ::memcpy(m_taps, taps, tapsLength * sizeof(float));
+ ::memset(m_buffer, 0, tapsLength * sizeof(float));
+ m_currentBufferPosition = 0;
+}
+
+CFIRFilter::~CFIRFilter()
+{
+ delete[] m_taps;
+ delete[] m_buffer;
+}
+
+inline void CFIRFilter::ProcessSampleBlock(uint8* voice, int length)
+{
+ for(int i = 0; i < length; i += 2)
+ {
+ float input = (float)(short)MAKEWORD(voice[i+1], voice[i]);
+ float output = 0.0f;
+ int iTaps = 0;
+
+ // Buffer latest sample into delay line
+ m_buffer[m_currentBufferPosition] = input;
+
+ for(int i = m_currentBufferPosition; i >= 0; i--)
+ {
+ output += m_taps[iTaps++] * m_buffer[i];
+ }
+
+ for(int i = m_tapsLength - 1; i > m_currentBufferPosition; i--)
+ {
+ output += m_taps[iTaps++] * m_buffer[i];
+ }
+
+ m_currentBufferPosition = (m_currentBufferPosition + 1) % m_tapsLength;
+
+ //write processed sample back
+ voice[i] = HIBYTE((short)output);
+ voice[i+1] = LOBYTE((short)output);
+ }
+}
+
+
diff --git a/ambed/cfirfilter.h b/ambed/cfirfilter.h
new file mode 100644
index 0000000..85026fb
--- /dev/null
+++ b/ambed/cfirfilter.h
@@ -0,0 +1,51 @@
+//
+// cfirfilter.h
+// ambed
+//
+// Created by Jean-Luc Deltombe (LX3JL) on 26/04/2017.
+// Copyright © 2015 Jean-Luc Deltombe (LX3JL). All rights reserved.
+//
+// ----------------------------------------------------------------------------
+// This file is part of ambed.
+//
+// xlxd 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.
+//
+// xlxd 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 Foobar. If not, see .
+// ----------------------------------------------------------------------------
+// FIRFilter by Geoffrey Merck F4FXL / KC3FRA
+
+#ifndef cfirfilter_h
+#define cfirfilter_h
+
+#include "csampleblockprocessor.h"
+
+class CFIRFilter : CSampleBlockProcessor
+{
+public :
+ //Constructor
+ CFIRFilter(const float* taps, int tapsLength);
+
+ // Destructor
+ ~CFIRFilter();
+
+ // Processing
+ void ProcessSampleBlock(uint8* voice, int length);
+
+private:
+ float* m_taps;
+ int m_tapsLength;
+ float* m_buffer;
+ int m_currentBufferPosition;
+};
+
+#endif //cfirfilter_h
+
diff --git a/ambed/cfixedgain.cpp b/ambed/cfixedgain.cpp
new file mode 100644
index 0000000..600df13
--- /dev/null
+++ b/ambed/cfixedgain.cpp
@@ -0,0 +1,53 @@
+//
+// cfixedgain.cpp
+// ambed
+//
+// Created by Jean-Luc Deltombe (LX3JL) on 28/04/2017.
+// Copyright © 2015 Jean-Luc Deltombe (LX3JL). All rights reserved.
+//
+// ----------------------------------------------------------------------------
+// This file is part of ambed.
+//
+// xlxd 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.
+//
+// xlxd 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 Foobar. If not, see .
+// ----------------------------------------------------------------------------
+// Geoffrey Merck F4FXL / KC3FRA AGC
+
+#include "cfixedgain.h"
+#include
+
+////////////////////////////////////////////////////////////////////////////////////////
+// constructor
+
+CFixedGain::CFixedGain(float gaindB)
+{
+ m_gaindB = gaindB;
+ m_gainLinear = pow(10.0f, m_gaindB/20.0f);
+}
+
+////////////////////////////////////////////////////////////////////////////////////////
+// processing
+
+inline void CFixedGain::ProcessSampleBlock(uint8* voice, int length)
+{
+ for(int i = 0; i < length; i += 2)
+ {
+ float input = (float)(short)MAKEWORD(voice[i+1], voice[i]);
+ //apply gain
+ float output = input * m_gainLinear;
+
+ //write processed sample back
+ voice[i] = HIBYTE((short)output);
+ voice[i+1] = LOBYTE((short)output);
+ }
+}
\ No newline at end of file
diff --git a/ambed/cfixedgain.h b/ambed/cfixedgain.h
new file mode 100644
index 0000000..eadac47
--- /dev/null
+++ b/ambed/cfixedgain.h
@@ -0,0 +1,45 @@
+//
+// cfixedgain.h
+// ambed
+//
+// Created by Jean-Luc Deltombe (LX3JL) on 26/04/2017.
+// Copyright © 2015 Jean-Luc Deltombe (LX3JL). All rights reserved.
+//
+// ----------------------------------------------------------------------------
+// This file is part of ambed.
+//
+// xlxd 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.
+//
+// xlxd 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 Foobar. If not, see .
+// ----------------------------------------------------------------------------
+// Geoffrey Merck F4FXL / KC3FRA
+
+#ifndef cfixedgain_h
+#define cfixedgain_h
+
+#include "csampleblockprocessor.h"
+
+class CFixedGain : CSampleBlockProcessor
+{
+public:
+ //Constructor
+ CFixedGain(float gaindB);
+
+ //processing
+ void ProcessSampleBlock(uint8* voice, int length);
+
+private:
+ float m_gaindB; //gain in dB
+ float m_gainLinear; //linearized gain
+};
+
+#endif /* cfixedgain_h */
\ No newline at end of file
diff --git a/ambed/csampleblockprocessor.h b/ambed/csampleblockprocessor.h
new file mode 100644
index 0000000..2c57f5f
--- /dev/null
+++ b/ambed/csampleblockprocessor.h
@@ -0,0 +1,38 @@
+//
+// csampleprocessor.h
+// ambed
+//
+// Created by Jean-Luc Deltombe (LX3JL) on 26/04/2017.
+// Copyright © 2015 Jean-Luc Deltombe (LX3JL). All rights reserved.
+//
+// ----------------------------------------------------------------------------
+// This file is part of ambed.
+//
+// xlxd 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.
+//
+// xlxd 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 Foobar. If not, see .
+// ----------------------------------------------------------------------------
+// Geoffrey Merck F4FXL / KC3FRA
+
+#ifndef csamplebloclprocessor_h
+#define csamplebloclprocessor_h
+
+#include "main.h"
+
+class CSampleBlockProcessor
+{
+public:
+ //processing
+ virtual void ProcessSampleBlock(uint8* voice, int length) = 0;
+};
+
+#endif /* csampleprocessor_h */
\ No newline at end of file
diff --git a/ambed/csignalprocessor.cpp b/ambed/csignalprocessor.cpp
new file mode 100644
index 0000000..21fba81
--- /dev/null
+++ b/ambed/csignalprocessor.cpp
@@ -0,0 +1,94 @@
+//
+// cagc.cpp
+// ambed
+//
+// Created by Jean-Luc Deltombe (LX3JL) on 28/04/2017.
+// Copyright © 2015 Jean-Luc Deltombe (LX3JL). All rights reserved.
+//
+// ----------------------------------------------------------------------------
+// This file is part of ambed.
+//
+// xlxd 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.
+//
+// xlxd 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 Foobar. If not, see .
+// ----------------------------------------------------------------------------
+// Geoffrey Merck F4FXL / KC3FRA AGC
+
+#include "main.h"
+#include "csignalprocessor.h"
+
+#if USE_AGC == 1
+#include "cagc.h"
+#else
+#include "cfixedgain.h"
+#endif
+
+#if USE_BANDPASSFILTER == 1
+#include "cfirfilter.h"
+#endif
+
+////////////////////////////////////////////////////////////////////////////////////////
+// constructor
+
+CSignalProcessor::CSignalProcessor(float gaindB)
+{
+#if USE_BANDPASSFILTER
+ m_sampleProcessors.push_back((CSampleBlockProcessor*)new CFIRFilter(FILTER_TAPS, FILTER_TAPS_LENGTH));
+#endif
+#if USE_AGC == 1
+ m_sampleProcessors.push_back((CSampleBlockProcessor*)new CAGC(gaindB));
+#else
+ m_sampleProcessors.push_back((CSampleBlockProcessor*)new CFixedGain(gaindB));
+#endif
+}
+
+////////////////////////////////////////////////////////////////////////////////////////
+// destructor
+
+CSignalProcessor::~CSignalProcessor()
+{
+ for(int i = 0; i < m_sampleProcessors.size(); i++)
+ {
+ delete m_sampleProcessors[i];
+ }
+}
+
+////////////////////////////////////////////////////////////////////////////////////////
+// processing
+
+void CSignalProcessor::Process(uint8* voice, int length)
+{
+ /*float sample;
+ int j;*/
+ auto processorsSize = m_sampleProcessors.size();
+
+ for(int j = 0; j < processorsSize; j++)
+ {
+ m_sampleProcessors[j]->ProcessSampleBlock(voice, length);
+ }
+
+ /*for(int i = 0; i < length; i += 2)
+ {
+ //Get the sample
+ sample = (float)(short)MAKEWORD(voice[i+1], voice[i]);
+
+ for(j = 0; j < processorsSize; j++)
+ {
+ sample = m_sampleProcessors[j]->ProcessSample(sample);
+ }
+
+ //write processed sample back
+ voice[i] = HIBYTE((short)sample);
+ voice[i+1] = LOBYTE((short)sample);
+ }*/
+}
\ No newline at end of file
diff --git a/ambed/csignalprocessor.h b/ambed/csignalprocessor.h
new file mode 100644
index 0000000..a1081d7
--- /dev/null
+++ b/ambed/csignalprocessor.h
@@ -0,0 +1,48 @@
+//
+// csignalprocessor.h
+// ambed
+//
+// Created by Jean-Luc Deltombe (LX3JL) on 26/04/2017.
+// Copyright © 2015 Jean-Luc Deltombe (LX3JL). All rights reserved.
+//
+// ----------------------------------------------------------------------------
+// This file is part of ambed.
+//
+// xlxd 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.
+//
+// xlxd 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 Foobar. If not, see .
+// ----------------------------------------------------------------------------
+// Geoffrey Merck F4FXL / KC3FRA
+
+#ifndef csignalprocessor_h
+#define csignalprocessor_h
+
+#include
+#include "csampleblockprocessor.h"
+
+class CSignalProcessor
+{
+public:
+ //Constructor
+ CSignalProcessor(float gaindB);
+
+ //Destructor
+ ~CSignalProcessor();
+
+ //Processing
+ void Process(uint8* voice, int length);
+
+private:
+ std::vector m_sampleProcessors;
+};
+
+#endif /* csignalprocessor_h */
\ No newline at end of file
diff --git a/ambed/cusb3xxxinterface.cpp b/ambed/cusb3xxxinterface.cpp
index c8eb461..c15801c 100644
--- a/ambed/cusb3xxxinterface.cpp
+++ b/ambed/cusb3xxxinterface.cpp
@@ -152,7 +152,7 @@ void CUsb3xxxInterface::Task(void)
{
Queue = Channel->GetVoiceQueue();
CVoicePacket *clone = new CVoicePacket(VoicePacket);
- clone->ApplyGain(Channel->GetSpeechGain());
+ Channel->ProcessSignal(*clone);
Queue->push(clone);
Channel->ReleaseVoiceQueue();
}
diff --git a/ambed/cvocodecchannel.cpp b/ambed/cvocodecchannel.cpp
index 0212424..7a10d41 100644
--- a/ambed/cvocodecchannel.cpp
+++ b/ambed/cvocodecchannel.cpp
@@ -27,7 +27,6 @@
#include "cvocodecchannel.h"
#include "cvocodecinterface.h"
-
////////////////////////////////////////////////////////////////////////////////////////
// constructor
@@ -39,6 +38,7 @@ CVocodecChannel::CVocodecChannel(CVocodecInterface *InterfaceIn, int iChIn, CVoc
m_InterfaceOut = InterfaceOut;
m_iChannelOut = iChOut;
m_iSpeechGain = iSpeechGain;
+ m_signalProcessor = new CSignalProcessor((float)m_iSpeechGain);
}
////////////////////////////////////////////////////////////////////////////////////////
@@ -47,6 +47,7 @@ CVocodecChannel::CVocodecChannel(CVocodecInterface *InterfaceIn, int iChIn, CVoc
CVocodecChannel::~CVocodecChannel()
{
PurgeAllQueues();
+ delete m_signalProcessor;
}
////////////////////////////////////////////////////////////////////////////////////////
@@ -92,6 +93,15 @@ uint8 CVocodecChannel::GetCodecOut(void) const
return m_InterfaceOut->GetChannelCodec(m_iChannelOut);
}
+////////////////////////////////////////////////////////////////////////////////////////
+// processing
+
+void CVocodecChannel::ProcessSignal(CVoicePacket& voicePacket)
+{
+ m_signalProcessor->Process(voicePacket.GetVoice(), voicePacket.GetVoiceSize());
+}
+
+
////////////////////////////////////////////////////////////////////////////////////////
// queues helpers
diff --git a/ambed/cvocodecchannel.h b/ambed/cvocodecchannel.h
index 4848c87..9726b9d 100644
--- a/ambed/cvocodecchannel.h
+++ b/ambed/cvocodecchannel.h
@@ -27,6 +27,8 @@
#define cvocodecchannel_h
#include "cpacketqueue.h"
+#include "csignalprocessor.h"
+#include "cvoicepacket.h"
////////////////////////////////////////////////////////////////////////////////////////
// class
@@ -54,6 +56,9 @@ public:
int GetChannelOut(void) const { return m_iChannelOut; }
int GetSpeechGain(void) const { return m_iSpeechGain; }
+ //Processing
+ void ProcessSignal(CVoicePacket& voicePacket);
+
// interfaces
bool IsInterfaceIn(const CVocodecInterface *interface) { return (interface == m_InterfaceIn); }
bool IsInterfaceOut(const CVocodecInterface *interface) { return (interface == m_InterfaceOut); }
@@ -92,6 +97,8 @@ protected:
// settings
int m_iSpeechGain;
+private:
+ CSignalProcessor* m_signalProcessor;
};
////////////////////////////////////////////////////////////////////////////////////////
diff --git a/ambed/cvoicepacket.cpp b/ambed/cvoicepacket.cpp
index 0fc05f7..3cfb66e 100644
--- a/ambed/cvoicepacket.cpp
+++ b/ambed/cvoicepacket.cpp
@@ -69,18 +69,3 @@ void CVoicePacket::SetVoice(const uint8 *voice, int size)
::memcpy(m_uiVoice, voice, m_iSize);
}
-
-////////////////////////////////////////////////////////////////////////////////////////
-// gain
-
-void CVoicePacket::ApplyGain(int dB)
-{
- float mult = pow(10, dB/20.0);
- for ( int i = 0; i < m_iSize; i += 2 )
- {
- float smp = (float)(short)MAKEWORD(m_uiVoice[i+1], m_uiVoice[i]);
- smp *= mult;
- m_uiVoice[i] = HIBYTE((short)smp);
- m_uiVoice[i+1] = LOBYTE((short)smp);
- }
-}
diff --git a/ambed/cvoicepacket.h b/ambed/cvoicepacket.h
index 7dbefc3..bb8e6ce 100644
--- a/ambed/cvoicepacket.h
+++ b/ambed/cvoicepacket.h
@@ -58,9 +58,6 @@ public:
// set
void SetVoice(const uint8 *, int);
- // gain
- void ApplyGain(int);
-
protected:
// data
int m_iSize;
diff --git a/ambed/main.h b/ambed/main.h
index 931badc..bdd512f 100644
--- a/ambed/main.h
+++ b/ambed/main.h
@@ -68,9 +68,14 @@
#define CODEC_AMBE2PLUS 2
// Transcoding speech gains
-#define CODECGAIN_AMBEPLUS -10 // in dB
+#define CODECGAIN_AMBEPLUS -10 // in dB
#define CODECGAIN_AMBE2PLUS +10 // in dB
+// Transcoding Tweaks
+#define USE_AGC 0
+#define AGC_CLAMPING 3 //clamps the AGC gain to +- this value
+#define USE_BANDPASSFILTER 1
+
// Timeouts -----------------------------------------------------
#define STREAM_ACTIVITY_TIMEOUT 3 // in seconds
@@ -96,6 +101,39 @@ typedef unsigned int uint;
#define LOWORD(dw) ((uint16)(uint32)(dw & 0x0000FFFF))
#define HIWORD(dw) ((uint16)((((uint32)(dw)) >> 16) & 0xFFFF))
+////////////////////////////////////////////////////////////////////////////////////////
+// FIR Filter coefficients computed to be the closest to the recommended filter in
+// Documentation
+//
+// Following GNU Octave script was used
+/*
+pkg load signal;
+fsamp = 8000;
+fcuts = [300 400 3000 3400];
+mags = [0 1 0];
+devs = [0.2 1 0.2];
+
+[n,Wn,beta,ftype] = kaiserord(fcuts,mags,devs,fsamp);
+n = n + rem(n,2);
+hh = fir1(n,Wn,ftype,kaiser(n+1,beta),'noscale');
+
+freqz(hh);
+[H,f] = freqz(hh,1,1024,fsamp);
+plot(f,abs(H))
+disp(hh);
+grid
+*/
+
+#if USE_BANDPASSFILTER == 1
+
+const float FILTER_TAPS[] {
+-0.05063341f, -0.00060337f, -0.08892498f, -0.02026701f, -0.05940750f, -0.10977641f, 0.03244024f, -0.22304499f,
+0.11452865f, 0.72500000f, 0.11452865f, -0.22304499f, 0.03244024f, -0.10977641f, -0.05940750f, -0.02026701f,
+-0.08892498f, -0.00060337f, -0.05063341f };
+#define FILTER_TAPS_LENGTH 19
+
+#endif
+
////////////////////////////////////////////////////////////////////////////////////////
// global objects