Rename the IIR filter class.

FMControl.cpp

@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2020,2021 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2020,2021,2024 by Jonathan Naylor G4KLX
  *
  *   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
@@ -48,13 +48,13 @@ m_filterStage3(NULL)
     assert(txAudioGain > 0.0F);
     assert(rxAudioGain > 0.0F);
 
-    m_preEmphasis  = new CIIRDirectForm1Filter(8.315375384336983F, -7.03334621603483F,0.0F,1.0F, 0.282029168302153F,0.0F, PREEMPHASIS_GAIN_DB);
+    m_preEmphasis  = new CIIR(8.315375384336983F,  -7.03334621603483F,0.0F,    1.0F,  0.282029168302153F,  0.0F, PREEMPHASIS_GAIN_DB);
-    m_deEmphasis   = new CIIRDirectForm1Filter(0.07708787090460224F, 0.07708787090460224F,0.0F, 1.0F, -0.8458242581907955F,0.0F, DEEMPHASIS_GAIN_DB);
+    m_deEmphasis   = new CIIR(0.07708787090460224F, 0.07708787090460224F,0.0F, 1.0F, -0.8458242581907955F, 0.0F, DEEMPHASIS_GAIN_DB);
 
     // Chebyshev type 1 0.2dB cheby type 1 3rd order 300-2700Hz fs=8000
-    m_filterStage1 = new CIIRDirectForm1Filter(0.29495028f, 0.0f, -0.29495028f, 1.0f, -0.61384624f, -0.057158668f, FILTER_GAIN_DB);
+    m_filterStage1 = new CIIR(0.29495028f, 0.0f,  -0.29495028f, 1.0f, -0.61384624f, -0.057158668f, FILTER_GAIN_DB);
-    m_filterStage2 = new CIIRDirectForm1Filter(1.0f, 2.0f, 1.0f, 1.0f, 0.9946123f, 0.6050482f, FILTER_GAIN_DB);
+    m_filterStage2 = new CIIR(1.0f,        2.0f,  1.0f,         1.0f, 0.9946123f,   0.6050482f,    FILTER_GAIN_DB);
-    m_filterStage3 = new CIIRDirectForm1Filter(1.0f, -2.0f, 1.0f, 1.0f, -1.8414584f, 0.8804949f, FILTER_GAIN_DB);
+    m_filterStage3 = new CIIR(1.0f,        -2.0f, 1.0f,         1.0f, -1.8414584f,  0.8804949f,    FILTER_GAIN_DB);
 }
 
 CFMControl::~CFMControl()

FMControl.h

@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2020,2021 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2020,2021,2024 by Jonathan Naylor G4KLX
  *
  *   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
@@ -21,7 +21,7 @@
 
 #include "FMNetwork.h"
 #include "Defines.h"
-#include "IIRDirectForm1Filter.h"
+#include "IIR.h"
 
 // Uncomment this to dump audio to a raw audio file
 // The file will be written in same folder as executable
@@ -49,11 +49,11 @@ private:
 	bool        m_deEmphasisOn;
     bool        m_enabled;
 	CRingBuffer<unsigned char> m_incomingRFAudio;
-	CIIRDirectForm1Filter* m_preEmphasis;
+	CIIR*       m_preEmphasis;
-	CIIRDirectForm1Filter* m_deEmphasis;
+	CIIR*       m_deEmphasis;
-	CIIRDirectForm1Filter* m_filterStage1;
+	CIIR*       m_filterStage1;
-	CIIRDirectForm1Filter* m_filterStage2;
+	CIIR*       m_filterStage2;
-	CIIRDirectForm1Filter* m_filterStage3;
+	CIIR*       m_filterStage3;
 };
 
 #endif

IIR.cpp

@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2015-2020 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2015-2020,2024 by Jonathan Naylor G4KLX
  *   Copyright (C) 2020 by Geoffrey Merck - F4FXL KC3FRA
  *
  *   This program is free software; you can redistribute it and/or modify
@@ -17,10 +17,11 @@
  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
-#include "IIRDirectForm1Filter.h"
+#include "IIR.h"
-#include "math.h"
 
-CIIRDirectForm1Filter::CIIRDirectForm1Filter(float b0, float b1, float b2, float , float a1, float a2, float addtionalGaindB) :
+#include <cmath>
+
+CIIR::CIIR(float b0, float b1, float b2, float , float a1, float a2, float addtionalGaindB) :
 m_x2(0.0F),
 m_y2(0.0F),
 m_x1(0.0F),
@@ -32,29 +33,29 @@ m_a1(a1),
 m_a2(a2),
 m_additionalGainLin(0.0F)
 {
-  m_additionalGainLin = ::powf(10.0F, addtionalGaindB / 20.0F);
+    m_additionalGainLin = ::powf(10.0F, addtionalGaindB / 20.0F);
 }
 
-float CIIRDirectForm1Filter::filter(float sample)
+CIIR::~CIIR()
 {
-  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()
+float CIIR::filter(float sample)
 {
-  m_x1 = 0.0f;
+    float output = m_b0 * sample + m_b1 * m_x1 + m_b2 * m_x2 - m_a1 * m_y1 - m_a2 * m_y2;
-  m_x2 = 0.0f;
+
-  m_y1 = 0.0f;
+    m_x2 = m_x1;
-  m_y2 = 0.0f;
+    m_y2 = m_y1;  
+    m_x1 = sample;
+    m_y1 = output;
+
+    return output * m_additionalGainLin;
+}
+
+void CIIR::reset()
+{
+    m_x1 = 0.0F;
+    m_x2 = 0.0F;
+    m_y1 = 0.0F;
+    m_y2 = 0.0F;
 }

IIR.h

@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2015-2020 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2015-2020,2024 by Jonathan Naylor G4KLX
  *   Copyright (C) 2020 by Geoffrey Merck - F4FXL KC3FRA
  *
  *   This program is free software; you can redistribute it and/or modify
@@ -17,34 +17,33 @@
  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
-#if !defined(IIRDIRECTFORM1FILTER_H)
+#if !defined(IIR_H)
-#define	IIRDIRECTFORM1FILTER_H
+#define	IIR_H
 
-class CIIRDirectForm1Filter
+class CIIR
 {
 public:
-  CIIRDirectForm1Filter(float b0, float b1, float b2, float, float a1, float a2, float additionalGaindB);
+	CIIR(float b0, float b1, float b2, float, float a1, float a2, float additionalGaindB);
-  float filter(float sample);
+	~CIIR();
-  void reset();
+
+	float filter(float sample);
+
+	void reset();
 
 private:
-// delay line
+	// Delay line
-  float m_x2; // x[n-2]
+	float m_x2;		// x[n-2]
-  float m_y2; // y[n-2]
+	float m_y2;		// y[n-2]
-  float m_x1; // x[n-1]
+	float m_x1;		// x[n-1]
-  float m_y1; // y[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;
+	// Coefficients
+	float m_b0;
+	float m_b1;
+	float m_b2;
+	float m_a1;
+	float m_a2;
+	float m_additionalGainLin;
 };
 
-
+#endif
-#endif

MMDVMHost.vcxproj

@@ -204,7 +204,7 @@
     <ClInclude Include="Golay24128.h" />
     <ClInclude Include="Hamming.h" />
     <ClInclude Include="DMRLookup.h" />
-    <ClInclude Include="IIRDirectForm1Filter.h" />
+    <ClInclude Include="IIR.h" />
     <ClInclude Include="LCDproc.h" />
     <ClInclude Include="Log.h" />
     <ClInclude Include="M17Control.h" />
@@ -315,7 +315,7 @@
     <ClCompile Include="Golay2087.cpp" />
     <ClCompile Include="Golay24128.cpp" />
     <ClCompile Include="Hamming.cpp" />
-    <ClCompile Include="IIRDirectForm1Filter.cpp" />
+    <ClCompile Include="IIR.cpp" />
     <ClCompile Include="LCDproc.cpp" />
     <ClCompile Include="Log.cpp" />
     <ClCompile Include="M17Control.cpp" />

MMDVMHost.vcxproj.filters

@@ -317,7 +317,7 @@
     <ClInclude Include="FMControl.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="IIRDirectForm1Filter.h">
+    <ClInclude Include="IIR.h">
       <Filter>Header Files</Filter>
     </ClInclude>
     <ClInclude Include="PseudoTTYController.h">
@@ -625,7 +625,7 @@
     <ClCompile Include="FMControl.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="IIRDirectForm1Filter.cpp">
+    <ClCompile Include="IIR.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
     <ClCompile Include="PseudoTTYController.cpp">

Version.h

@@ -19,6 +19,6 @@
 #if !defined(VERSION_H)
 #define	VERSION_H
 
-const char* VERSION = "20240429";
+const char* VERSION = "20240430";
 
 #endif