Merge pull request #581 from F4FXL/FM_Ext

Add Pre and De emphasis

FMControl.cpp

@@ -20,14 +20,13 @@
 
 #include <string>
 
-const uint8_t BIT_MASK_TABLE[] = { 0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U };
-
-#define WRITE_BIT(p,i,b) p[(i)>>3] = (b) ? (p[(i)>>3] | BIT_MASK_TABLE[(i)&7]) : (p[(i)>>3] & ~BIT_MASK_TABLE[(i)&7])
-#define READ_BIT(p,i)    (p[(i)>>3] & BIT_MASK_TABLE[(i)&7])
+#define EMPHASIS_GAIN_DB 0 //Gain needs to be the same for pre an deeemphasis
 
 CFMControl::CFMControl(CFMNetwork* network) :
 m_network(network),
-m_enabled(false)
+m_enabled(false),
+m_preemphasis(0.3889703087993727F, -0.3290005228984741F, 0.0F, 1.0F, 0.282029168302153F, 0.0F, EMPHASIS_GAIN_DB),
+m_deemphasis(1.0F, 0.282029168302153F, 0.0F, 0.3889703087993727F, -0.3290005228984741F, 0.0F, EMPHASIS_GAIN_DB)
 {
     assert(network != NULL);
 }
@@ -67,6 +66,9 @@ bool CFMControl::writeModem(const unsigned char* data, unsigned int length)
     }
 
     // De-emphasise the data and any other processing needed (maybe a low-pass filter to remove the CTCSS)
+    for(unsigned int i = 0U; i < nSamples; i++) {
+        samples[i] = m_deemphasis.filter(samples[i]);
+    }
 
     unsigned char out[350U];
     unsigned int nOut = 0U;
@@ -102,6 +104,9 @@ unsigned int CFMControl::readModem(unsigned char* data, unsigned int space)
     }
 
     // Pre-emphasise the data and other stuff.
+    for(unsigned int i = 0U; i < nSamples; i++) {
+        samples[i] = m_preemphasis.filter(samples[i]);
+    }
 
     // Pack the floating point data (+1.0 to -1.0) to packed 12-bit samples (+2047 - -2048)
     unsigned int pack = 0U;

FMControl.h

@@ -21,6 +21,7 @@
 
 #include "FMNetwork.h"
 #include "Defines.h"
+#include "IIRDirectForm1Filter.h"
 
 class CFMControl {
 public:
@@ -38,6 +39,8 @@ public:
 private:
 	CFMNetwork* m_network;
     bool        m_enabled;
+	CIIRDirectForm1Filter m_preemphasis;
+	CIIRDirectForm1Filter m_deemphasis;
 };
 
 #endif

IIRDirectForm1Filter.cpp

@@ -0,0 +1,56 @@
+/*
+ *   Copyright (C) 2015-2020 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 "IIRDirectForm1Filter.h"
+#include "math.h"
+
+CIIRDirectForm1Filter::CIIRDirectForm1Filter(float b0, float b1, float b2, float , float a1, float a2, float addtionalGaindB) :
+m_b0(b0),
+m_b1(b1),
+m_b2(b2),
+m_a1(a1),
+m_a2(a2),
+m_additionalGainLin(::powf(10.0F, addtionalGaindB / 20.0F))
+{
+
+}
+
+float CIIRDirectForm1Filter::filter(float sample)
+{
+  float output = m_b0 * sample
+               + m_b1 * m_x1 
+               + m_b2 * m_x2
+               - m_a1 * m_y1 
+               - m_a2 * m_y2;
+
+  m_x2 = m_x1;
+  m_y2 = m_y1;  
+  m_x1 = sample;
+  m_y1 = output;
+
+  return output * m_additionalGainLin;
+}
+
+void CIIRDirectForm1Filter::reset()
+{
+  m_x1 = 0.0f;
+  m_x2 = 0.0f;
+  m_y1 = 0.0f;
+  m_y2 = 0.0f;
+}

IIRDirectForm1Filter.h

@@ -0,0 +1,50 @@
+/*
+ *   Copyright (C) 2015-2020 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.
+ */
+
+#if !defined(IIRDIRECTFORM1FILTER_H)
+#define	IIRDIRECTFORM1FILTER_H
+
+class CIIRDirectForm1Filter
+{
+public:
+  CIIRDirectForm1Filter(float b0, float b1, float b2, float, float a1, float a2, float additionalGaindB);
+  float filter(float sample);
+  void reset();
+
+private:
+// delay line
+  float m_x2; // x[n-2]
+  float m_y2; // y[n-2]
+  float m_x1; // x[n-1]
+  float m_y1; // y[n-1]
+  
+  // coefficients
+  // FIR
+  float m_b0;
+  float m_b1;
+  float m_b2;
+  // IIR
+  float m_a1;
+  float m_a2;
+
+  float m_additionalGainLin;
+};
+
+
+#endif

Makefile

@@ -9,7 +9,7 @@ LDFLAGS = -g
 OBJECTS = \
 		AMBEFEC.o BCH.o BPTC19696.o CASTInfo.o Conf.o CRC.o Display.o DMRControl.o DMRCSBK.o DMRData.o DMRDataHeader.o DMREMB.o DMREmbeddedData.o DMRFullLC.o \
 		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTA.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
-		DStarSlowData.o FMControl.o FMNetwork.o Golay2087.o Golay24128.o Hamming.o I2CController.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o \
+		DStarSlowData.o FMControl.o FMNetwork.o Golay2087.o Golay24128.o Hamming.o I2CController.o IIRDirectForm1Filter.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o \
 		ModemSerialPort.o Mutex.o NetworkInfo.o Nextion.o NullDisplay.o NullModem.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o \
 		NXDNLayer3.o NXDNLICH.o NXDNLookup.o NXDNNetwork.o NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o \
 		P25Trellis.o P25Utils.o POCSAGControl.o POCSAGNetwork.o QR1676.o RemoteControl.o RS129.o RS241213.o RSSIInterpolator.o SerialController.o SerialPort.o \

Makefile.Pi

@@ -9,7 +9,7 @@ LDFLAGS = -g -L/usr/local/lib
 OBJECTS = \
 		AMBEFEC.o BCH.o BPTC19696.o CASTInfo.o Conf.o CRC.o Display.o DMRControl.o DMRCSBK.o DMRData.o DMRDataHeader.o DMREMB.o DMREmbeddedData.o DMRFullLC.o \
 		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTA.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
-		DStarSlowData.o FMControl.o FMNetwork.o Golay2087.o Golay24128.o Hamming.o I2CController.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o \
+		DStarSlowData.o FMControl.o FMNetwork.o Golay2087.o Golay24128.o Hamming.o I2CController.o IIRDirectForm1Filter.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o \
 		ModemSerialPort.o Mutex.o NetworkInfo.o Nextion.o NullDisplay.o NullModem.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o \
 		NXDNLayer3.o NXDNLICH.o NXDNLookup.o NXDNNetwork.o NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o \
 		P25Trellis.o P25Utils.o POCSAGControl.o POCSAGNetwork.o QR1676.o RemoteControl.o RS129.o RS241213.o RSSIInterpolator.o SerialController.o SerialPort.o \

Makefile.Pi.Adafruit

@@ -10,7 +10,7 @@ LDFLAGS = -g -L/usr/local/lib
 OBJECTS = \
 		AMBEFEC.o BCH.o BPTC19696.o CASTInfo.o Conf.o CRC.o Display.o DMRControl.o DMRCSBK.o DMRData.o DMRDataHeader.o DMREMB.o DMREmbeddedData.o DMRFullLC.o \
 		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTA.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
-		DStarSlowData.o FMControl.o FMNetwork.o Golay2087.o Golay24128.o Hamming.o HD44780.o I2CController.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o \
+		DStarSlowData.o FMControl.o FMNetwork.o Golay2087.o Golay24128.o Hamming.o HD44780.o I2CController.o IIRDirectForm1Filter.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o \
 		ModemSerialPort.o Mutex.o NetworkInfo.o Nextion.o NullDisplay.o NullModem.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o \
 		NXDNLayer3.o NXDNLICH.o NXDNLookup.o NXDNNetwork.o NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o \
 		P25Trellis.o P25Utils.o POCSAGControl.o POCSAGNetwork.o QR1676.o RemoteControl.o RS129.o RS241213.o RSSIInterpolator.o SerialController.o SerialPort.o \

Makefile.Pi.HD44780

@@ -9,7 +9,7 @@ LDFLAGS = -g -L/usr/local/lib
 OBJECTS = \
 		AMBEFEC.o BCH.o BPTC19696.o CASTInfo.o Conf.o CRC.o Display.o DMRControl.o DMRCSBK.o DMRData.o DMRDataHeader.o DMREMB.o DMREmbeddedData.o DMRFullLC.o \
 		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTA.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
-		DStarSlowData.o FMControl.o FMNetwork.o Golay2087.o Golay24128.o Hamming.o HD44780.o I2CController.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o \
+		DStarSlowData.o FMControl.o FMNetwork.o Golay2087.o Golay24128.o Hamming.o HD44780.o I2CController.o IIDirectForm1Filter.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o \
 		ModemSerialPort.o Mutex.o NetworkInfo.o Nextion.o NullDisplay.o NullModem.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o \
 		NXDNLayer3.o NXDNLICH.o NXDNLookup.o NXDNNetwork.o NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o \
 		P25Trellis.o P25Utils.o POCSAGControl.o POCSAGNetwork.o QR1676.o RemoteControl.o RS129.o RS241213.o RSSIInterpolator.o SerialController.o SerialPort.o \

Makefile.Pi.OLED

@@ -9,7 +9,7 @@ LDFLAGS = -g -L/usr/local/lib
 OBJECTS = \
 		AMBEFEC.o BCH.o BPTC19696.o CASTInfo.o Conf.o CRC.o Display.o DMRControl.o DMRCSBK.o DMRData.o DMRDataHeader.o DMREMB.o DMREmbeddedData.o DMRFullLC.o \
 		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTA.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
-		DStarSlowData.o FMControl.o FMNetwork.o Golay2087.o Golay24128.o Hamming.o I2CController.o OLED.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o \
+		DStarSlowData.o FMControl.o FMNetwork.o Golay2087.o Golay24128.o Hamming.o I2CController.o IIRDirectForm1Filter.o OLED.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o \
 		ModemSerialPort.o Mutex.o NetworkInfo.o Nextion.o NullDisplay.o NullModem.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o \
 		NXDNLayer3.o NXDNLICH.o NXDNLookup.o NXDNNetwork.o NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o \
 		P25Trellis.o P25Utils.o POCSAGControl.o POCSAGNetwork.o QR1676.o RemoteControl.o RS129.o RS241213.o RSSIInterpolator.o SerialController.o SerialPort.o \

Makefile.Pi.PCF8574

@@ -10,7 +10,7 @@ LDFLAGS = -g -L/usr/local/lib
 OBJECTS = \
 		AMBEFEC.o BCH.o BPTC19696.o CASTInfo.o Conf.o CRC.o Display.o DMRControl.o DMRCSBK.o DMRData.o DMRDataHeader.o DMREMB.o DMREmbeddedData.o DMRFullLC.o \
 		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTA.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
-		DStarSlowData.o FMControl.o FMNetwork.o Golay2087.o Golay24128.o Hamming.o HD44780.o I2CController.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o \
+		DStarSlowData.o FMControl.o FMNetwork.o Golay2087.o Golay24128.o Hamming.o HD44780.o I2CController.o IIRDirectForm1Filter.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o \
 		ModemSerialPort.o Mutex.o NetworkInfo.o Nextion.o NullDisplay.o NullModem.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o \
 		NXDNLayer3.o NXDNLICH.o NXDNLookup.o NXDNNetwork.o NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o \
 		P25Trellis.o P25Utils.o POCSAGControl.o POCSAGNetwork.o QR1676.o RemoteControl.o RS129.o RS241213.o RSSIInterpolator.o SerialController.o SerialPort.o \

Makefile.Solaris

@@ -9,7 +9,7 @@ LDFLAGS = -g
 OBJECTS = \
 		AMBEFEC.o BCH.o BPTC19696.o CASTInfo.o Conf.o CRC.o Display.o DMRControl.o DMRCSBK.o DMRData.o DMRDataHeader.o DMREMB.o DMREmbeddedData.o DMRFullLC.o \
 		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTA.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
-		DStarSlowData.o FMControl.o FMNetwork.o Golay2087.o Golay24128.o Hamming.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o ModemSerialPort.o Mutex.o \
+		DStarSlowData.o FMControl.o FMNetwork.o Golay2087.o Golay24128.o Hamming.o IIRDirectForm1Filter.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o ModemSerialPort.o Mutex.o \
 		NetworkInfo.o Nextion.o NullDisplay.o NullModem.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o NXDNLayer3.o NXDNLICH.o NXDNLookup.o \
 		NXDNNetwork.o NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o P25Trellis.o P25Utils.o POCSAGControl.o \
 		POCSAGNetwork.o QR1676.o RemoteControl.o RS129.o RS241213.o RSSIInterpolator.o SerialController.o SerialPort.o SHA256.o StopWatch.o Sync.o TFTSerial.o \