diff --git a/src/data/DamarisFFT.py b/src/data/DamarisFFT.py
index 8e75ee5..a5af062 100644
--- a/src/data/DamarisFFT.py
+++ b/src/data/DamarisFFT.py
@@ -225,3 +225,13 @@ class DamarisFFT:
self.y[ 0 ] = numpy.sqrt( self.y[ 0 ] ** 2 + self.y[ 1 ] ** 2 )
self.y[ 1 ] *= 0 # self.y[0].copy()
return self
+
+ def ppm(self, f_ref):
+ """
+ Return result scaled to PPM compared to f_ref
+
+ :param f_ref: larmor frequency in Hz
+ :return:
+ """
+ self.y /= f_ref*1e6
+ return self
\ No newline at end of file
diff --git a/src/gui/damaris.glade b/src/gui/damaris.glade
index 5ac3474..51a0248 100644
--- a/src/gui/damaris.glade
+++ b/src/gui/damaris.glade
@@ -596,7 +596,8 @@ log10
False
lin
log
-log10
+log10
+ppm
@@ -1471,7 +1472,7 @@ Homepage http://www.fkp.physik.tu-darmstadt.de/damaris/
Python frontend written by Christopher Schmitt, Achim Gädke, Markus Rosenstihl and Christian Tacke
Backends written by Achim Gädke, Markus Rosenstihl, Christian Tacke, tested by Holger Stork
-The drivers included in the backend may use propietary interfaces.
+The drivers included in the backend may use proprietary interfaces.
The source code distribution may include commercial third party's code,
which is specially marked and not covered by this license.