Add optional over deviation blanking.

FM.cpp

@@ -39,6 +39,7 @@ m_hangTimer(),
 m_filterStage1(  724,   1448,   724, 32768, -37895, 21352),
 m_filterStage2(32768,      0,-32768, 32768, -50339, 19052),
 m_filterStage3(32768, -65536, 32768, 32768, -64075, 31460),
+m_blanking(),
 m_useCOS(true),
 m_rxBoost(1U)
 {
@@ -78,7 +79,9 @@ void CFM::samples(bool cos, q15_t* samples, uint8_t length)
     }
     
     // Only let audio through when relaying audio
-    if (m_state != FS_RELAYING && m_state != FS_KERCHUNK)
+    if (m_state == FS_RELAYING || m_state == FS_KERCHUNK)
+      currentSample = m_blanking.process(currentSample);
+    else
       currentSample = 0U;
 
     currentSample *= m_rxBoost;
@@ -141,7 +144,7 @@ uint8_t CFM::setAck(const char* rfAck, uint8_t speed, uint16_t frequency, uint8_
   return m_rfAck.setParams(rfAck, speed, frequency, level, level);
 }
 
-uint8_t CFM::setMisc(uint16_t timeout, uint8_t timeoutLevel, uint8_t ctcssFrequency, uint8_t ctcssThreshold, uint8_t ctcssLevel, uint8_t kerchunkTime, uint8_t hangTime, bool useCOS, uint8_t rxBoost)
+uint8_t CFM::setMisc(uint16_t timeout, uint8_t timeoutLevel, uint8_t ctcssFrequency, uint8_t ctcssThreshold, uint8_t ctcssLevel, uint8_t kerchunkTime, uint8_t hangTime, bool useCOS, uint8_t rxBoost, uint8_t maxDev)
 {
   m_useCOS  = useCOS;
   m_rxBoost = q15_t(rxBoost);
@@ -151,6 +154,7 @@ uint8_t CFM::setMisc(uint16_t timeout, uint8_t timeoutLevel, uint8_t ctcssFreque
   m_hangTimer.setTimeout(hangTime, 0U);
 
   m_timeoutTone.setParams(timeoutLevel);
+  m_blanking.setParams(maxDev, timeoutLevel);
 
   uint8_t ret = m_ctcssRX.setParams(ctcssFrequency, ctcssThreshold);
   if (ret != 0U)

FM.h

@@ -21,6 +21,7 @@
 
 #include "Config.h"
 
+#include "FMBlanking.h"
 #include "FMCTCSSRX.h"
 #include "FMCTCSSTX.h"
 #include "FMTimeout.h"
@@ -53,7 +54,7 @@ public:
 
   uint8_t setCallsign(const char* callsign, uint8_t speed, uint16_t frequency, uint8_t time, uint8_t holdoff, uint8_t highLevel, uint8_t lowLevel, bool callsignAtStart, bool callsignAtEnd);
   uint8_t setAck(const char* rfAck, uint8_t speed, uint16_t frequency, uint8_t minTime, uint16_t delay, uint8_t level);
-  uint8_t setMisc(uint16_t timeout, uint8_t timeoutLevel, uint8_t ctcssFrequency, uint8_t ctcssThreshold, uint8_t ctcssLevel, uint8_t kerchunkTime, uint8_t hangTime, bool useCOS, uint8_t rxBoost);
+  uint8_t setMisc(uint16_t timeout, uint8_t timeoutLevel, uint8_t ctcssFrequency, uint8_t ctcssThreshold, uint8_t ctcssLevel, uint8_t kerchunkTime, uint8_t hangTime, bool useCOS, uint8_t rxBoost, uint8_t maxDev);
 
 private:
   CFMKeyer             m_callsign;
@@ -74,6 +75,7 @@ private:
   CFMDirectFormI       m_filterStage1;
   CFMDirectFormI       m_filterStage2;
   CFMDirectFormI       m_filterStage3;
+  CFMBlanking          m_blanking;
   bool                 m_useCOS;
   q15_t                m_rxBoost;
 

FMBlanking.cpp

@@ -0,0 +1,82 @@
+/*
+ *   Copyright (C) 2020 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
+ *   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 "Config.h"
+#include "Globals.h"
+#include "FMBlanking.h"
+
+// 2000 Hz sine wave at 24000 Hz sample rate
+const q31_t TONE[] = {0, 16384, 28378, 32767, 28378, 16384, 0, -16383, -28377, -32767, -28377, -16383};
+
+const uint8_t TONE_LEN = 12U;
+
+const uint32_t BLEEP_LEN = 2400U;   // 100ms
+
+CFMBlanking::CFMBlanking() :
+m_posValue(0),
+m_negValue(0),
+m_level(128 * 128),
+m_running(false),
+m_pos(0U),
+m_n(0U)
+{
+}
+
+void CFMBlanking::setParams(uint8_t value, uint8_t level)
+{
+  m_posValue = q15_t(value * 128);
+  m_negValue = -m_posValue;
+
+  m_level = q15_t(level * 128);
+}
+
+q15_t CFMBlanking::process(q15_t sample)
+{
+  if (m_posValue == 0)
+    return sample;
+
+  if (!m_running) {
+    if (sample >= m_posValue) {
+      m_running = true;
+      m_pos = 0U;
+      m_n   = 0U;
+    } else if (sample <= m_negValue) {
+      m_running = true;
+      m_pos = 0U;
+      m_n   = 0U;
+    }
+  }
+
+  if (!m_running)
+    return sample;
+
+  if (m_pos <= BLEEP_LEN) {
+    q31_t value = TONE[m_n++] * m_level;
+    sample = q15_t(__SSAT((value >> 15), 16));
+    if (m_n >= TONE_LEN)
+      m_n = 0U;
+  } else {
+    sample = 0;
+  }
+
+  m_pos++;
+  if (m_pos >= 12000U)
+    m_running = false;
+
+  return sample;
+}

FMBlanking.h

@@ -0,0 +1,41 @@
+/*
+ *   Copyright (C) 2020 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
+ *   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(FMBlanking_H)
+#define  FMBlanking_H
+
+#include "Config.h"
+
+class CFMBlanking {
+public:
+  CFMBlanking();
+
+  void setParams(uint8_t value, uint8_t level);
+
+  q15_t process(q15_t sample);
+
+private:
+  q15_t    m_posValue;
+  q15_t    m_negValue;
+  q15_t    m_level;
+  bool     m_running;
+  uint32_t m_pos;
+  uint8_t  m_n;
+};
+
+#endif

SerialPort.cpp

@@ -408,7 +408,7 @@ uint8_t CSerialPort::setFMParams2(const uint8_t* data, uint8_t length)
 
 uint8_t CSerialPort::setFMParams3(const uint8_t* data, uint8_t length)
 {
-  if (length < 9U)
+  if (length < 10U)
     return 4U;
 
   uint16_t timeout        = data[0U] * 5U;
@@ -424,8 +424,9 @@ uint8_t CSerialPort::setFMParams3(const uint8_t* data, uint8_t length)
   bool     useCOS         = (data[7U] & 0x01U) == 0x01U;
 
   uint8_t  rxBoost        = data[8U];
+  uint8_t  maxDev         = data[9U];
 
-  return fm.setMisc(timeout, timeoutLevel, ctcssFrequency, ctcssThreshold, ctcssLevel, kerchunkTime, hangTime, useCOS, rxBoost);
+  return fm.setMisc(timeout, timeoutLevel, ctcssFrequency, ctcssThreshold, ctcssLevel, kerchunkTime, hangTime, useCOS, rxBoost, maxDev);
 }
 
 uint8_t CSerialPort::setMode(const uint8_t* data, uint8_t length)