HcalTDC.cc

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#include "SimCalorimetry/HcalSimAlgos/interface/HcalTDC.h"
#include "CalibFormats/HcalObjects/interface/HcalCalibrations.h"
#include "CalibFormats/HcalObjects/interface/HcalDbService.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"

HcalTDC::HcalTDC(unsigned int thresholdDAC) : theTDCParameters(), 
                          theDbService(0),
                          theDAC(thresholdDAC),
                          theRandGaussQ(0) {}

HcalTDC::~HcalTDC() {
  if (theRandGaussQ) delete theRandGaussQ;
}

void HcalTDC::timing(const CaloSamples& lf, HcalUpgradeDataFrame& digi) const {

  float TDC_Threshold = getThreshold(digi.id());
  bool alreadyOn = false;
  int tdcBins = theTDCParameters.nbins();
  // start with a loop over 10 samples
  bool hasTDCValues=true;
  if (lf.preciseSize()==0 ) hasTDCValues=false;

  // if (hasTDCValues)
  //   std::cout << digi.id() 
  //          << " threshold: " << TDC_Threshold
  //          << " hasTDCValues: " << hasTDCValues 
  //          << '\n';
  for (int ibin = 0; ibin < lf.size(); ++ibin) {
    /*
    If in a given 25ns bunch/time sample, the pulse is above
    TDC_Thresh already, then TDC_RisingEdge=0 if it was low in the
    last precision bin on the previous bunch crossing, otherwise,
    TDC_RisingEdge=63 if the pulse never crosses the threshold
    having started off, then the special code is 62 and then
    one can still have a TDC_FallingEdge that is valid.  If the pulse
    never falls below threshold having started above threshold (or
    goes above threshold in the bunch crossing and doesn't come down),
    then TDC_FallingEdge=.  If the pulse never went above
    threshold, then TDC_RisingEdge=63 and
    TDC_FallingEdge=62.
    */
    // special codes
    int TDC_RisingEdge = (alreadyOn) ? theTDCParameters.alreadyTransitionCode() 
      : theTDCParameters.noTransitionCode();
    int TDC_FallingEdge = (alreadyOn) ? theTDCParameters.noTransitionCode() : 
      theTDCParameters.alreadyTransitionCode();
    int preciseBegin = ibin * tdcBins;
    int preciseEnd = preciseBegin + tdcBins;
    if ( hasTDCValues) {
      // std::cout << " alreadyOn: " << alreadyOn << '\n';
      for(int i = preciseBegin; i < preciseEnd; ++i) { 
      //    std::cout << " preciseBin: " << i
      //                << " preciseAt(i): " << lf.preciseAt(i);
    if (alreadyOn) {
      if( (i%3 == 0) && (lf.preciseAt(i) < TDC_Threshold) ) {
        alreadyOn = false;
        TDC_FallingEdge = i-preciseBegin;
        // std::cout << " falling ";
      }
    } else {
      if (lf.preciseAt(i) > TDC_Threshold) {
        alreadyOn = true;
        TDC_RisingEdge = i-preciseBegin;
        // the flag for hasn't gone low yet
        TDC_FallingEdge = theTDCParameters.noTransitionCode();
        // std::cout << " rising ";
      }
    }
    // std::cout << '\n';
      }
    }
    // change packing to allow for special codes
    int packedTDC = TDC_RisingEdge + (tdcBins*2) * TDC_FallingEdge;
    digi.setSample(ibin, digi.adc(ibin), packedTDC, true);
    // if ( hasTDCValues) {
    //   std::cout << " sample: " << ibin 
    //      << " adc: " << digi.adc(ibin)
    //      << " fC: " << digi[ibin].nominal_fC()
    //      << " risingEdge: " << TDC_RisingEdge
    //      << " fallingEdge: " << TDC_FallingEdge
    //      << " packedTDC: " << packedTDC
    //      << std::endl;
    // }
  } // loop over bunch crossing bins
}

double HcalTDC::getThreshold(const HcalGenericDetId & detId) const {
  // subtract off pedestal and noise once
  double pedestal = theDbService->getHcalCalibrations(detId).pedestal(0);
  double pedestalWidth = theDbService->getHcalCalibrationWidths(detId).pedestal(0);
  // here the TDCthreshold_ is a multiple of the least significant bit 
  // for the TDC portion of the QIE.  The nominal reference is 40 uA which is
  // divided by an 8 bit DAC.  This means the least significant bit is 0.135 uA
  // in the TDC circuit or 3.74 uA at the input current.

  // the pedestal is assumed to be evenly distributed in time with some
  // random variation.  No hysteresis is implemented here.

  double const lsb(3.74);
  return lsb*theDAC - theRandGaussQ->shoot(pedestal,  pedestalWidth)/theTDCParameters.deltaT()/theTDCParameters.nbins();
}

void HcalTDC::setRandomEngine(CLHEP::HepRandomEngine & engine) {
  theRandGaussQ = new CLHEP::RandGaussQ(engine);
}

void HcalTDC::setDbService(const HcalDbService * service) {
  theDbService = service;
}