diff --git a/plugins/samplesource/testsource/readme.md b/plugins/samplesource/testsource/readme.md
index 8f64bffbd..8ddcb39df 100644
--- a/plugins/samplesource/testsource/readme.md
+++ b/plugins/samplesource/testsource/readme.md
@@ -82,6 +82,13 @@ This controls the generator sample rate in samples per second.
   - **No**: No modulation
   - **AM**: Amplitude modulation (AM)
   - **FM**: Frequency modulation (FM)
+  - **P0**: Pattern 0 is a binary pattern
+    - Pulse width: 150 samples
+    - Sync pattern: 010 at full amplitude
+    - Binary pattern LSB first on 3 bits from 0 to 7 at 0.3 amplitude
+  - **P1**: Pattern 1 is a sawtooth pattern
+    - Pulse width: 1000 samples
+    - Starts at full amplitude then amplitude decreases linearly down to zero
   
 <h3>5: Modulating tone frequency</h3>
 
diff --git a/sdrgui/gui/glspectrum.cpp b/sdrgui/gui/glspectrum.cpp
index eeeff9fb2..f7d9767d4 100644
--- a/sdrgui/gui/glspectrum.cpp
+++ b/sdrgui/gui/glspectrum.cpp
@@ -90,9 +90,9 @@ GLSpectrum::GLSpectrum(QWidget* parent) :
 	for (int i = 1; i < 240; i++)
 	{
 	    QColor c;
-	    int val = i < 60 ? 128 + (60-i) : 128;
-	    int sat = i < 60 ? 140 + i : i < 180 ? 200 : 200 - (i-180);
-	    c.setHsl(239 - i, sat, val);
+	    int light = i < 60 ? 128 + (60-i) : 128;
+	    int sat   = i < 60 ? 140 + i : i < 180 ? 200 : 200 - (i-180);
+	    c.setHsl(239 - i, sat, light);
         ((quint8*)&m_histogramPalette[i])[0] = c.red();
         ((quint8*)&m_histogramPalette[i])[1] = c.green();
         ((quint8*)&m_histogramPalette[i])[2] = c.blue();