Digitization: Apply time offset also in event-by-event mode.

sim/detectors/sts/CbmStsDigitize.cxx

@@ -189,7 +189,7 @@ void CbmStsDigitize::Exec(Option_t* /*opt*/)
   // --- Generate noise from previous to current event time
   if (fParSim->Noise()) {
     Int_t nNoise         = 0;
-    Double_t tNoiseStart = fNofEvents ? eventTimePrevious : 0.;
+    Double_t tNoiseStart = fNofEvents ? eventTimePrevious : 1000.;
     Double_t tNoiseEnd   = fCurrentEventTime;
     for (auto& entry : fModules)
       nNoise += entry.second->GenerateNoise(tNoiseStart, tNoiseEnd);

sim/response/base/CbmDigitizationSource.cxx

@@ -280,7 +280,7 @@ Int_t CbmDigitizationSource::ReadEvent(UInt_t event)
   }
 
   // In the event-by-event mode, get the respective event from the first
-  // input; the event time is zero.
+  // input; the event time is fStartTime.
   if (fEventMode) return ReadEventByEvent(event);
 
   // If the last used input set was exhausted, switch to a the next one
@@ -347,7 +347,7 @@ Int_t CbmDigitizationSource::ReadEventByEvent(UInt_t event)
     fCurrentEntryId = input->GetNextEntry();
 
   // Set entry properties
-  fCurrentTime = 0.;
+  fCurrentTime = fTimeStart;
   LOG(info) << "DigitizationSource: Event " << event << " at t = " << fCurrentTime << " ns"
             << " from input " << fCurrentInputId << " (entry " << fCurrentEntryId << ")";