NFM Modulator: Cleanup level meter code. Use experimental max value for modulation swing calculation

plugins/channeltx/modnfm/nfmmod.cpp

@@ -134,7 +134,8 @@ void NFMMod::modulateSample()
     pullAF(t);
     calculateLevel(t);
 
-    m_modPhasor += (m_running.m_fmDeviation / (float) m_running.m_audioSampleRate) * m_bandpass.filter(t) * (M_PI / 1208.0f);
+    // 378 = 302 * 1.25; 302 = number of filter taps (established experimentally)
+    m_modPhasor += (m_running.m_fmDeviation / (float) m_running.m_audioSampleRate) * m_bandpass.filter(t) * (M_PI / 378.0f);
     m_modSample.real(cos(m_modPhasor) * 32678.0f);
     m_modSample.imag(sin(m_modPhasor) * 32678.0f);
 }

plugins/channeltx/modnfm/nfmmodgui.ui

@@ -345,7 +345,7 @@
          </size>
         </property>
         <property name="toolTip">
-         <string>Audio input volume</string>
+         <string>Audio input gain</string>
         </property>
         <property name="maximum">
          <number>100</number>
@@ -367,7 +367,7 @@
          </size>
         </property>
         <property name="toolTip">
-         <string>Audio input volume level</string>
+         <string>Audio input gain value</string>
         </property>
         <property name="statusTip">
          <string/>
@@ -388,6 +388,9 @@
           <verstretch>0</verstretch>
          </sizepolicy>
         </property>
+        <property name="toolTip">
+         <string>Volume meter. White line is 100% and shoul not be exceeded (red zone)</string>
+        </property>
        </widget>
       </item>
      </layout>

sdrbase/gui/levelmeter.cpp

@@ -3,6 +3,7 @@
  * Modifications made to:
  * - use the widget horizontally
  * - differentiate each area with a different color
+ * - allow overload by 25% with indication of 100% threshold and overload
 **
 ** Copyright (C) 2015 The Qt Company Ltd.
 ** Contact: http://www.qt.io/licensing/
@@ -130,45 +131,31 @@ void LevelMeter::paintEvent(QPaintEvent *event)
     QPainter painter(this);
     painter.fillRect(rect(), Qt::black);
 
+    // red zone on top half
+    QRect barTop = rect();
+    barTop.setBottom(0.5 * rect().height());
+    barTop.setLeft(0.75* rect().width());
+    painter.fillRect(barTop, Qt::red);
+
     QRect bar = rect();
 
-    // old
+    // 100% full height white line
+    bar.setLeft(0.75* rect().width() - 2);
+    bar.setRight(0.75* rect().width());
+    painter.fillRect(bar, Qt::white);
 
-//    bar.setTop(rect().top() + (1.0 - m_peakHoldLevel) * rect().height());
-//    bar.setBottom(bar.top() + 5);
-//    painter.fillRect(bar, m_rmsColor);
-//    bar.setBottom(rect().bottom());
-//
-//    bar.setTop(rect().top() + (1.0 - m_decayedPeakLevel) * rect().height());
-//    painter.fillRect(bar, m_peakColor);
-//
-//    bar.setTop(rect().top() + (1.0 - m_rmsLevel) * rect().height());
-//    painter.fillRect(bar, m_rmsColor);
+    // Bottom moving gauge
 
-    // old v.2
+    bar.setTop(0.5 * rect().height());
 
-//    bar.setTop(rect().top() + (1.0 - m_peakHoldLevel) * rect().height());
-//    bar.setBottom(bar.top() + 5);
-//    painter.fillRect(bar, m_peakColor);
-//    bar.setBottom(rect().bottom());
-//
-//    bar.setTop(rect().top() + (1.0 - m_decayedPeakLevel) * rect().height());
-//    painter.fillRect(bar, m_decayedPeakColor);
-//
-//    bar.setTop(rect().top() + (1.0 - m_rmsLevel) * rect().height());
-//    painter.fillRect(bar, m_rmsColor);
-
-    // new
-
-    bar.setRight(rect().right() - (1.0 - m_peakHoldLevel) * rect().width());
+    bar.setRight(rect().right() - (1.0 - 0.75*m_peakHoldLevel) * rect().width());
     bar.setLeft(bar.right() - 5);
     painter.fillRect(bar, m_peakColor);
     bar.setLeft(rect().left());
 
-    bar.setRight(rect().right() - (1.0 - m_decayedPeakLevel) * rect().width());
+    bar.setRight(rect().right() - (1.0 - 0.75*m_decayedPeakLevel) * rect().width());
     painter.fillRect(bar, m_decayedPeakColor);
 
-    bar.setRight(rect().right() - (1.0 - m_rmsLevel) * rect().width());
+    bar.setRight(rect().right() - (1.0 - 0.75*m_rmsLevel) * rect().width());
     painter.fillRect(bar, m_rmsColor);
-
 }

sdrbase/gui/levelmeter.h

@@ -3,6 +3,7 @@
  * Modifications made to:
  * - use the widget horizontally
  * - differentiate each area with a different color
+ * - allow overload by 25% with indication of 100% threshold and overload
 **
 ** Copyright (C) 2015 The Qt Company Ltd.
 ** Contact: http://www.qt.io/licensing/