diff --git a/src/classes/PRunAsymmetry.cpp b/src/classes/PRunAsymmetry.cpp
index 27b2a4b4..36e33c14 100644
--- a/src/classes/PRunAsymmetry.cpp
+++ b/src/classes/PRunAsymmetry.cpp
@@ -471,7 +471,8 @@ bool PRunAsymmetry::PrepareData()
 // SubtractFixBkg
 //--------------------------------------------------------------------------
 /**
- * <p>Subtracts a fixed background from the raw data. The error propagation
+ * <p>Subtracts a fixed background from the raw data. The background is given
+ * in units of (1/ns). The error propagation
  * is done the following way: it is assumed that the error of the background
  * is Poisson like, i.e. \f$\Delta\mathrm{bkg} = \sqrt{\mathrm{bkg}}\f$.
  *
@@ -482,14 +483,14 @@ bool PRunAsymmetry::PrepareData()
  * and \f$ \mathrm{bkg} \f$ the fix given background.
  */
 bool PRunAsymmetry::SubtractFixBkg()
-{
+{  
   for (unsigned int i=0; i<fForward.size(); i++) {
-    fForwardErr.push_back(TMath::Sqrt(fForward[i]+fRunInfo->fBkgFix[0]));
-    fForward[i] -= fRunInfo->fBkgFix[0];
-    fBackwardErr.push_back(TMath::Sqrt(fBackward[i]+fRunInfo->fBkgFix[1]));
-    fBackward[i] -= fRunInfo->fBkgFix[1];
+    fForwardErr.push_back(TMath::Sqrt(fForward[i]+fRunInfo->fBkgFix[0] * fTimeResolution * 1.0e3));
+    fForward[i] -= fRunInfo->fBkgFix[0] * fTimeResolution * 1.0e3; // bkg per ns -> bkg per bin; 1.0e3: us -> ns
+    fBackwardErr.push_back(TMath::Sqrt(fBackward[i]+fRunInfo->fBkgFix[1] * fTimeResolution * 1.0e3));
+    fBackward[i] -= fRunInfo->fBkgFix[1] * fTimeResolution * 1.0e3; // bkg per ns -> bkg per bin; 1.0e3: us -> ns
   }
-
+  
   return true;
 }
 
@@ -575,12 +576,14 @@ bool PRunAsymmetry::SubtractEstimatedBkg()
     bkg[0] += fForward[i];
   errBkg[0] = TMath::Sqrt(bkg[0])/(end[0] - start[0] + 1);
   bkg[0] /= static_cast<double>(end[0] - start[0] + 1);
+//cout << endl << ">> bkg[0] = " << bkg[0];
 
   // backward
   for (unsigned int i=start[1]; i<end[1]; i++)
     bkg[1] += fBackward[i];
   errBkg[1] = TMath::Sqrt(bkg[1])/(end[0] - start[0] + 1);
   bkg[1] /= static_cast<double>(end[1] - start[1] + 1);
+//cout << endl << ">> bkg[1] = " << bkg[1] << endl;
 
   // correct error for forward, backward
   for (unsigned int i=0; i<fForward.size(); i++) {
diff --git a/src/classes/PRunSingleHisto.cpp b/src/classes/PRunSingleHisto.cpp
index 95c97050..b36457f7 100644
--- a/src/classes/PRunSingleHisto.cpp
+++ b/src/classes/PRunSingleHisto.cpp
@@ -752,7 +752,6 @@ bool PRunSingleHisto::PrepareViewData(PRawRunData* runData, const unsigned int h
     // evaluate function
     N0 = fMsrInfo->EvalFunc(funNo,fRunInfo->fMap,par);
   }
-//cout << endl << ">> N0 = " << N0;
 
   // get tau
   double tau;
@@ -775,7 +774,6 @@ bool PRunSingleHisto::PrepareViewData(PRawRunData* runData, const unsigned int h
   } else { // bkg fitted
     bkg = par[fRunInfo->fBkgFitParamNo-1];
   }
-//cout << endl << ">> bkg = " << bkg;
 
   double value  = 0.0;
   double expval;
@@ -796,9 +794,9 @@ cout << endl << "--------------------------------" << endl;
     if (((i-start) % fRunInfo->fPacking == 0) && (i != start)) { // fill data
       // in order that after rebinning the fit does not need to be redone (important for plots)
       // the value is normalize to per 1 nsec
-      normalizer = fRunInfo->fPacking * (fTimeResolution * 1e3); // fTimeResolution us->ns
+      normalizer = fRunInfo->fPacking * (fTimeResolution * 1.0e3); // fTimeResolution us->ns
       value /= normalizer;
-      time = ((double)(i-fRunInfo->fPacking)-t0)*fTimeResolution;
+      time = (((double)i-(double)(fRunInfo->fPacking-1)/2.0)-t0)*fTimeResolution;
       expval = TMath::Exp(+time/tau)/N0;
       fData.fValue.push_back(-1.0+expval*(value-bkg));
 //cout << endl << ">> i=" << i << ",t0=" << t0 << ",time=" << time << ",expval=" << expval << ",value=" << value << ",bkg=" << bkg << ",expval*(value-bkg)-1=" << expval*(value-bkg)-1.0;
diff --git a/src/include/PRunBase.h b/src/include/PRunBase.h
index d3dcd5f5..ae8963d8 100644
--- a/src/include/PRunBase.h
+++ b/src/include/PRunBase.h
@@ -87,7 +87,7 @@ class PRunBase
     PIntVector fParamNo;        ///< vector of parameter numbers for the specifc run
 
     PRunData fData;             ///< data to be fitted, viewed, i.e. binned data
-    double fTimeResolution;     ///< time resolution
+    double fTimeResolution;     ///< time resolution in (us)
     PIntVector fT0s;            ///< all t0's of a run! The derived classes will handle it
 
     virtual bool PrepareData() = 0; // pure virtual, i.e. needs to be implemented by the deriving class!!