Only use audio signal level for AM based modems

src/modules/modem/Modem.cpp

@@ -32,7 +32,7 @@ ModemArgInfo::ModemArgInfo(void) {
 }
 
 Modem::Modem() {
-    
+    useSignalOutput(false);
 }
 
 Modem::~Modem() {
@@ -108,3 +108,12 @@ void Modem::rebuildKit() {
 void Modem::clearRebuildKit() {
     refreshKit.store(false);
 }
+
+
+bool Modem::useSignalOutput() {
+    return _useSignalOutput.load();
+}
+
+void Modem::useSignalOutput(bool useOutput) {
+    _useSignalOutput.store(useOutput);
+}

src/modules/modem/Modem.h

@@ -152,8 +152,11 @@ public:
     void rebuildKit();
     void clearRebuildKit();
     
+    bool useSignalOutput();
+    void useSignalOutput(bool useOutput);
+    
 private:
     static ModemFactoryList modemFactories;
     static DefaultRatesList modemDefaultRates;
-    std::atomic_bool refreshKit;
+    std::atomic_bool refreshKit, _useSignalOutput;
 };

src/modules/modem/ModemAnalog.cpp

@@ -1,6 +1,6 @@
 #include "ModemAnalog.h"
 
-ModemAnalog::ModemAnalog() : aOutputCeil(1), aOutputCeilMA(1), aOutputCeilMAA(1) {
+ModemAnalog::ModemAnalog() : Modem(), aOutputCeil(1), aOutputCeilMA(1), aOutputCeilMAA(1) {
     
 }
 

src/modules/modem/ModemDigital.cpp

@@ -5,7 +5,7 @@ ModemDigitalOutput::ModemDigitalOutput() {
     
 }
 
-ModemDigital::ModemDigital() {
+ModemDigital::ModemDigital() : Modem() {
 #if ENABLE_DIGITAL_LAB
     digitalOut = nullptr;
 #endif

src/modules/modem/analog/ModemAM.cpp

@@ -2,6 +2,7 @@
 
 ModemAM::ModemAM() : ModemAnalog() {
     demodAM = ampmodem_create(0.5, 0.0, LIQUID_AMPMODEM_DSB, 0);
+    useSignalOutput(true);
 }
 
 ModemAM::~ModemAM() {

src/modules/modem/analog/ModemDSB.cpp

@@ -2,6 +2,7 @@
 
 ModemDSB::ModemDSB() : ModemAnalog() {
     demodAM_DSB = ampmodem_create(0.5, 0.0, LIQUID_AMPMODEM_DSB, 1);
+    useSignalOutput(true);
 }
 
 ModemDSB::~ModemDSB() {

src/modules/modem/analog/ModemLSB.cpp

@@ -11,6 +11,7 @@ ModemLSB::ModemLSB() : ModemAnalog() {
 	ssbShift = nco_crcf_create(LIQUID_NCO);
     nco_crcf_set_frequency(ssbShift,  (2.0 * M_PI) * 0.25);
     c2rFilt = firhilbf_create(5, 90.0);
+    useSignalOutput(true);
 }
 
 ModemBase *ModemLSB::factory() {

src/modules/modem/analog/ModemUSB.cpp

@@ -11,6 +11,7 @@ ModemUSB::ModemUSB() : ModemAnalog() {
 	ssbShift = nco_crcf_create(LIQUID_NCO);
     nco_crcf_set_frequency(ssbShift,  (2.0f * M_PI) * 0.25f);
     c2rFilt = firhilbf_create(5, 90.0);
+    useSignalOutput(true);
 }
 
 ModemBase *ModemUSB::factory() {