From 1d32eb021799cc1a9280df1f787217fca62664ab Mon Sep 17 00:00:00 2001
From: f4exb <f4exb06@gmail.com>
Date: Sun, 20 Aug 2017 00:56:50 +0200
Subject: [PATCH] AM demod: eliminate DC from demodulated output. Set volume
 AGC length to 50ms

---
 plugins/channelrx/demodam/amdemod.cpp       | 2 +-
 plugins/channelrx/demodam/amdemod.h         | 2 +-
 plugins/channelrx/demodam/amdemodplugin.cpp | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/plugins/channelrx/demodam/amdemod.cpp b/plugins/channelrx/demodam/amdemod.cpp
index 622619b97..105b77d08 100644
--- a/plugins/channelrx/demodam/amdemod.cpp
+++ b/plugins/channelrx/demodam/amdemod.cpp
@@ -33,7 +33,7 @@ AMDemod::AMDemod() :
 	m_magsqPeak(0.0f),
 	m_magsqCount(0),
 	m_movingAverage(40, 0),
-    m_volumeAGC(4800, 1.0),
+    m_volumeAGC(2400, 1.0),
     m_audioFifo(4, 48000),
     m_settingsMutex(QMutex::Recursive)
 {
diff --git a/plugins/channelrx/demodam/amdemod.h b/plugins/channelrx/demodam/amdemod.h
index a4b1720b7..5880d40ce 100644
--- a/plugins/channelrx/demodam/amdemod.h
+++ b/plugins/channelrx/demodam/amdemod.h
@@ -188,7 +188,7 @@ private:
         {
             Real demod = sqrt(magsq);
             m_volumeAGC.feed(demod);
-            demod /= m_volumeAGC.getValue();
+            demod = (demod - m_volumeAGC.getValue()) / m_volumeAGC.getValue();
 
             if (m_running.m_bandpassEnable)
             {
diff --git a/plugins/channelrx/demodam/amdemodplugin.cpp b/plugins/channelrx/demodam/amdemodplugin.cpp
index 2e4aed7ab..6bebc3d3c 100644
--- a/plugins/channelrx/demodam/amdemodplugin.cpp
+++ b/plugins/channelrx/demodam/amdemodplugin.cpp
@@ -7,7 +7,7 @@
 
 const PluginDescriptor AMDemodPlugin::m_pluginDescriptor = {
 	QString("AM Demodulator"),
-	QString("3.5.0"),
+	QString("3.6.0"),
 	QString("(c) Edouard Griffiths, F4EXB"),
 	QString("https://github.com/f4exb/sdrangel"),
 	true,