scaling in spectra corrected

JvanKatwijk · Aug 22, 2018 · d5f2373 · d5f2373
1 parent ee997c5
commit d5f2373
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Showing 3 changed files with 7 additions and 5 deletions.
diff --git a/spectrum-viewer/spectrum-viewer.cpp b/spectrum-viewer/spectrum-viewer.cpp
@@ -184,8 +184,9 @@ void	spectrumViewer::ViewSpectrum (double *X_axis,
 	                               double amp,
 	                               int32_t marker) {
 uint16_t	i;
+float	amp1	= amp / 100;
 
-	amp		= amp / 50.0 * (-get_db (0));
+	amp		= amp / 100.0 * (- get_db (0));
 	plotgrid	-> setAxisScale (QwtPlot::xBottom,
 				         (double)X_axis [0],
 				         X_axis [displaySize - 1]);
@@ -195,7 +196,7 @@ uint16_t	i;
 //				         get_db (0), 0);
 
 	for (i = 0; i < displaySize; i ++) 
-	   Y1_value [i] = get_db (amp * Y1_value [i]); 
+	   Y1_value [i] = get_db (amp1 * Y1_value [i]); 
 
 	spectrumCurve	-> setBaseline (get_db (0));
 	Y1_value [0]		= get_db (0);
@@ -207,7 +208,7 @@ uint16_t	i;
 }
 
 float	spectrumViewer::get_db (float x) {
-	return 10 * log10 ((x + 1) / (float)(normalizer));
+	return 20 * log10 ((x + 1) / (float)(normalizer));
 }
 
 void	spectrumViewer::setBitDepth	(int16_t d) {

diff --git a/src/ofdm/ofdm-decoder.cpp b/src/ofdm/ofdm-decoder.cpp
@@ -216,7 +216,7 @@ float	signal	= 0;
 	   signal += abs (v [(T_u + i) % T_u]);
 	signal	/= (carriers / 2);
 
-	return 10 * log10 ((signal + 0.005) / (noise + 0.005));
+	return 20 * log10 ((signal + 0.005) / (noise + 0.005));
 }
 
 
diff --git a/tii-viewer/tii-viewer.cpp b/tii-viewer/tii-viewer.cpp
@@ -170,6 +170,7 @@ void	tiiViewer::ViewSpectrum (double *X_axis,
 	                               double amp,
 	                               int32_t marker) {
 uint16_t	i;
+float	amp1	= amp / 100;
 
 	amp		= amp / 50.0 * (-get_db (0));
 	plotgrid	-> setAxisScale (QwtPlot::xBottom,
@@ -181,7 +182,7 @@ uint16_t	i;
 //				         get_db (0), 0);
 
 	for (i = 0; i < displaySize; i ++) 
-	   Y1_value [i] = get_db (amp * Y1_value [i]); 
+	   Y1_value [i] = get_db (amp1 * Y1_value [i]); 
 
 	spectrumCurve	-> setBaseline (get_db (0));
 	Y1_value [0]		= get_db (0);