1. Digitization starts from CbmEmcHit produced without energy treshold and at the end produces object EmcDigi. 
The sequence for digitizationis the following

CbmEmcHit ->EmcWaveform (via EmcHitToWaveform)-> EmcDigi (via EmcWaveformToDigi)

Reconstruction should start from EmcDigi.

2. EmcMapper. Class which provides mapping between unique index of crystal and TwoCoordinateIndex. If geometry is implemented in different way correspondent mapping should be implemented in EmcMapper. Mapping for Forward endcup is not implemented yet.
		
3. TwoCoordinateIndex. Object which contains 2 dimensional index of crystal and reference to its the neigbours. It simplify clustering algorithms.
		
4. NeighbourStore.h - typedef NeighbourStore which is set of TwoCoordinateIndex for neigbours of crystal#####################################################################################
see $(PANDAROOT)/emc
#revised classes            | source files
PndEmcWaveform              EmcData/PndEmcWaveform.cxx(.h)
PndEmcBump                  EmcData/PndEmcBump.cxx(.h)
PndEmcHitProducer           EmcDigi/PndEmcHitProducer.cxx(.h)
PndEmcHitsToWaveform        EmcDigi/PndEmcHitsToWaveform.cxx(.h)
PndEmcWaveformToDigi        EmcDigi/PndEmcWaveformToDigi.cxx(.h)
PndEmcDigiPar               EmcDigi/PndEmcDigiPar.cxx(.h)
PndEmcMakeCluster           EmcReco/PndEmcMakeCluster.cxx(.h)
PndEmcExpClusterSplitter    EmcReco/PndEmcExpClusterSplitter.cxx(.h) 
PndEmcContFact              PndEmcContFact.cxx(.h)
#new classes                | source files
PndEmcWaveformWriteoutBuffer EmcTimeBased/PndEmcWaveformWriteoutBuffer.cxx
PndEmcWaveformRingSorter     EmcTimeBased/PndEmcWaveformRingSorter.cxx
PndEmcWaveformSorterTask     EmcTimeBased/PndEmcWaveformSorterTask.cxx
PndEmcFpgaPar                EmcTimeBased/PndEmcFpgaPar.cxx
PndEmcDigiCalibrator         EmcTimeBased/PndEmcDigiCalibrator.cxx
PndEmcCorrBump               EmcTimeBased/PndEmcCorrBump.cxx
PndEmcAnalysis               EmcTimeBased/PndEmcAnalysis.cxx
# parameter file

####################################################################################
class                 changes                                         reason
####################################################################################
PndEmcWaveform      (1) mother class changed.
                    PndEmcWaveform: public FairMultiLinkedData      requirement of time-based simulation.
                    -->PndEmcWaveform: public FairTimeStamp        
								  	(2) new data members,
								  	Double_t fSampleRate;                           used to calculate time information.
								  	Double_t fBaselineValue;                        convenient for FPGA algorithm analysis.
								  	std::vector<Double_t>  fSignalError;            error of each sampling value in waveform.
								  	std::vector<Int_t>     fEvt;                    used to trace events a waveform comes from .

								  	static Double_t BarrelOverlapTime;              determine when waveforms pile up with
								  	static Double_t ForwardOverlapTime;             what overlapped time.
								  	static Double_t ShashylikOverlapTime;

PndEmcBump         (1) new data members,
								  	Int_t fEvtNo;                       					 	used to trace a bump from which event.
								  	Double_t fTimeStamp;                 					 	time information.


PndEmcHitProducer (1) member function: cleansortmclist            in this function, we tag all hits with its MC truch track identifier.
                                                                  so, we know a hit was produced by which primary track. 
                  (2) line 266,                                   skip points with zero deposited energy.
                  (3) line 267,268                                bug report, we can find points with negative track identifer.

PndEmcHitsToWaveform (1) new interface RunTimeBased()             requirements of time-based simulation.
                     (2) line 90,                                 switch for general simulation or time-based simulation.
                     (3) line 122, 134, 127,128                   new paramters for Forward Calor. waveform shape.
                     (4) line 181, 182                            create pulseshape for Forward part.
                     (5) line 376-378,454-456                     only time-based simulation
                     (6) more differences                         small changes wont affect final results
PndEmcWaveformToDigi (1) new interface RunTimeBased()             requirements of time-based simulation.
                     (2) line 72-76                               switch for general simulation or time-based simulation.
                     (3) line 196-247                             use FPGA feature extraction algorithm to do digitization (replace old version).
                     (4) line 292-304                             only for time-based simulation, load time-order-sorted waveforms
                     (5) line 395-403                             only for time-based simulation, load undetermined digis.

PndEmcDigi           (1) line 47 PndEmcDigi.h                 
                         new static data member
                         static TClonesArray* fDigiArrayTBD;     used for time-based simulation, digis in current event,
                                                                 if their timestamps fail to match,
                                                                 they will be pushed into this array and reused in next event for reconstruction.

################################################################################################################
new class                                              purpose
PndEmcWaveformWriteoutBuffer                           used to take care of all waveforms in time-based simulation.
PndEmcWaveformRingSorter 
PndEmcWaveformSorterTask                               used to produce pileup waveforms when condition is satisfied.
PndEmcFpgaPar                                          access to FPGA parameters setup.
PndEmcCorrBump                                         used to analysis a bump, for all digis in this bump, 
                                                       if their timestamps fail to match, they will be removed, 
                                                       and the bump will be remake.
PndEmcDigiCalibrator                                   calibrate digi timestamps, the calibrated time is used as a reference event time,
                                                       so we can group digis with closed timestamps.
PndEmcAnalysis                                         a helper class, used to save trees into tuples, we can 
                                                       judge whether each class works well or not.