Index: trunk/MagicSoft/Mars/msignal/MExtractTimeAndCharge.cc
===================================================================
--- trunk/MagicSoft/Mars/msignal/MExtractTimeAndCharge.cc	(revision 5358)
+++ trunk/MagicSoft/Mars/msignal/MExtractTimeAndCharge.cc	(revision 5359)
@@ -30,5 +30,8 @@
 //   and the signal at the same time. Uses the functions 
 //   FindTimeAndChargeHiGain() and FindTimeAndChargeLoGain() to extract the signal and 
-//   substract the pedestal value    
+//   substract the pedestal value.
+//
+//   If the flag fNoiseCalculation is set, the signal extractor should 
+//   calculate the pure noise contriubtion from a fixed window in time.
 //
 //   The following variables have to be set by the derived class and 
@@ -81,4 +84,5 @@
 // Sets: 
 // - fLoGainStartShift to fgLoGainStartShift+fgOffsetLoGain
+// - fNoiseCalculation to kFALSE 
 //
 MExtractTimeAndCharge::MExtractTimeAndCharge(const char *name, const char *title)
@@ -88,4 +92,5 @@
 
     SetLoGainStartShift();
+    SetNoiseCalculation(kFALSE);
 }
 
Index: trunk/MagicSoft/Mars/msignal/MExtractTimeAndCharge.h
===================================================================
--- trunk/MagicSoft/Mars/msignal/MExtractTimeAndCharge.h	(revision 5358)
+++ trunk/MagicSoft/Mars/msignal/MExtractTimeAndCharge.h	(revision 5359)
@@ -15,4 +15,6 @@
   Byte_t  fLoGainFirstSave;       //! Temporary variable to store the original position of low-gain start slice
   Float_t fLoGainStartShift;      // Shift to start searching the low-gain signal obtained from the high-gain times.
+
+  Bool_t  fNoiseCalculation;      // Flag if the extractor is used to determine the noise contribution from a pedestal file.
   
 protected:
@@ -30,5 +32,8 @@
 
   Int_t  ReadEnv(const TEnv &env, TString prefix, Bool_t print);
-  
+
+  Bool_t IsNoiseCalculation()   {  return fNoiseCalculation;  }
+
+    
 public:
 
@@ -36,5 +41,6 @@
   
   void SetLoGainStartShift( const Float_t f=fgLoGainStartShift )  { fLoGainStartShift = f + fOffsetLoGain;  }
-
+  void SetNoiseCalculation( const Bool_t b=kFALSE              )  { fNoiseCalculation = b;   }
+    
   void Print(Option_t *o) const;