CSCStripElectronicsSim.cc

Go to the documentation of this file.

#include "FWCore/MessageLogger/interface/MessageLogger.h"
#include "SimMuon/CSCDigitizer/src/CSCStripElectronicsSim.h"
#include "SimMuon/CSCDigitizer/src/CSCAnalogSignal.h"
#include "SimMuon/CSCDigitizer/src/CSCCrosstalkGenerator.h"
#include "SimMuon/CSCDigitizer/src/CSCStripConditions.h"
#include "DataFormats/CSCDigi/interface/CSCComparatorDigi.h"
#include "DataFormats/CSCDigi/interface/CSCStripDigi.h"
#include "Geometry/CSCGeometry/interface/CSCLayer.h"
#include "Geometry/CSCGeometry/interface/CSCChamberSpecs.h"
#include "Geometry/CSCGeometry/interface/CSCLayerGeometry.h"
#include "SimMuon/CSCDigitizer/src/CSCDetectorHit.h"

#include "CLHEP/Units/GlobalPhysicalConstants.h"
#include "CLHEP/Units/GlobalSystemOfUnits.h"  
#include "CLHEP/Random/RandGaussQ.h"

#include "boost/bind.hpp"  
#include <list>
#include <cassert>

// This is CSCStripElectronicsSim.cc

CSCStripElectronicsSim::CSCStripElectronicsSim(const edm::ParameterSet & p)
: CSCBaseElectronicsSim(p),
  theAmpResponse(theShapingTime, CSCStripAmpResponse::RADICAL),
  theComparatorThreshold(20.),
  theComparatorNoise(0.),
  theComparatorRMSOffset(2.),
  theComparatorSaturation(1057.),
  theComparatorWait(50.),
  theComparatorDeadTime(100.),
  theDaqDeadTime(200.),
  theTimingOffset(0.),
  nScaBins_(p.getParameter<int>("nScaBins")),
  doSuppression_(p.getParameter<bool>("doSuppression")),
  doCrosstalk_(p.getParameter<bool>("doCrosstalk")),
  theStripConditions(0),
  theCrosstalkGenerator(0),
  theComparatorClockJump(2),
  sca_time_bin_size(50.),
  sca_peak_bin(p.getParameter<int>("scaPeakBin")),
  theComparatorTimeBinOffset(p.getParameter<double>("comparatorTimeBinOffset")),
  theComparatorTimeOffset(p.getParameter<double>("comparatorTimeOffset")),
  theComparatorSamplingTime(p.getParameter<double>("comparatorSamplingTime")),
  theSCATimingOffsets(p.getParameter<std::vector<double> >("scaTimingOffsets"))
{

  if(doCrosstalk_) {
    theCrosstalkGenerator = new CSCCrosstalkGenerator();
  }

  fillAmpResponse();
}


CSCStripElectronicsSim::~CSCStripElectronicsSim() {
  if(doCrosstalk_) {
    delete theCrosstalkGenerator;
  }
}

void CSCStripElectronicsSim::initParameters() {
  nElements = theLayerGeometry->numberOfStrips();
  theComparatorThreshold = 20.;
  //selfTest();

  //calculate the offset to the peak
  float averageDistance = theLayer->surface().position().mag();
  theAverageTimeOfFlight = averageDistance * cm / c_light; // Units of c_light: mm/ns
  int chamberType = theSpecs->chamberType();
  theTimingOffset = theShapingTime + theAverageTimeOfFlight
         + theBunchTimingOffsets[chamberType];
//TODO make sure config gets overridden
  theSignalStartTime = theTimingOffset
                     - (sca_peak_bin-1) * sca_time_bin_size;
  theSignalStopTime = theSignalStartTime + nScaBins_*sca_time_bin_size;
  theNumberOfSamples = nScaBins_*static_cast<int>(sca_time_bin_size/theSamplingTime);

}  


int CSCStripElectronicsSim::readoutElement(int strip) const {
  return theLayerGeometry->channel(strip);
}


float CSCStripElectronicsSim::calculateAmpResponse(float t) const
{
  return theAmpResponse.calculateAmpResponse(t);
}


CSCAnalogSignal CSCStripElectronicsSim::makeNoiseSignal(int element, CLHEP::HepRandomEngine* engine) {
  std::vector<float> noiseBins(nScaBins_);
  CSCAnalogSignal tmpSignal(element, sca_time_bin_size, noiseBins);
  if(doNoise_) {
    theStripConditions->noisify(layerId(), tmpSignal, engine);
  }
  // now rebin it
  std::vector<float> binValues(theNumberOfSamples);
  for(int ibin=0; ibin < theNumberOfSamples; ++ibin) {
     binValues[ibin] = tmpSignal.getValue(ibin*theSamplingTime);
  }
  CSCAnalogSignal finalSignal(element, theSamplingTime, binValues, 0., theSignalStartTime);
  return finalSignal;
}


float CSCStripElectronicsSim::comparatorReading(const CSCAnalogSignal & signal,
                                                float time,
                                                CLHEP::HepRandomEngine* engine) const {
   return std::min(signal.getValue(time), theComparatorSaturation)
     +  theComparatorRMSOffset * CLHEP::RandGaussQ::shoot(engine);
}


void
CSCStripElectronicsSim::runComparator(std::vector<CSCComparatorDigi> & result, CLHEP::HepRandomEngine* engine) {
  // first, make a list of all the comparators we actually
  // need to run
  std::list<int> comparatorsWithSignal;
  CSCSignalMap::iterator signalMapItr;
  for(signalMapItr = theSignalMap.begin();
      signalMapItr != theSignalMap.end(); ++signalMapItr) {
    // Elements in signal map count from 1
    // 1,2->0,  3,4->1,  5,6->2, ...
    comparatorsWithSignal.push_back( ((*signalMapItr).first-1)/2 );
  }
  // no need to sort
  comparatorsWithSignal.unique();
  for(std::list<int>::iterator listItr = comparatorsWithSignal.begin();
      listItr != comparatorsWithSignal.end(); ++listItr) {
    int iComparator = *listItr;
    // find signal1 and signal2
    // iComparator counts from 0
    // icomp =0->1,2,  =1->3,4,  =2->5,6, ...
    const CSCAnalogSignal & signal1 = find(readoutElement(iComparator*2 + 1), engine);
    const CSCAnalogSignal & signal2 = find(readoutElement(iComparator*2 + 2), engine);
    for(float time = theSignalStartTime +theComparatorTimeOffset; 
        time < theSignalStopTime-theComparatorWait; 
        time += theComparatorSamplingTime) 
    {
      if(comparatorReading(signal1, time, engine) > theComparatorThreshold
         || comparatorReading(signal2, time, engine) > theComparatorThreshold) {
     // wait a bit, so we can run the comparator at the signal peak
        float comparatorTime = time;
        time += theComparatorWait;
          
        float height1 = comparatorReading(signal1, time, engine);
        float height2 = comparatorReading(signal2, time, engine);
        int output = 0; 
        int strip = 0;
     // distrip logic; comparator output is for pairs of strips:
         // hit  bin  dec
         // x--- 100   4
         // -x-- 101   5
         // --x- 110   6
         // ---x 111   7
         // just to prevent a copy
         const CSCAnalogSignal * mainSignal = 0;
         // pick the higher of the two strips in the pair
         if(height1 > height2) {
           mainSignal = &signal1;
           float leftStrip = 0.;
           if(iComparator > 0)  {
             leftStrip = comparatorReading(find(readoutElement(iComparator*2), engine), time, engine);
           }
           // if this strip is higher than either of its neighbors, make a comparator digi
           if(leftStrip < height1 && height1 > theComparatorThreshold) {
             output = (leftStrip < height2);
             strip = iComparator*2 + 1;
           }
         } else {
           mainSignal = &signal2;
           float rightStrip = 0.;
           if(iComparator*2+3 <= nElements) {
             rightStrip = comparatorReading(find(readoutElement(iComparator*2+3), engine), time, engine);
           }
           if(rightStrip < height2 && height2 > theComparatorThreshold) {
             output = (height1 < rightStrip);
             strip = iComparator*2 + 2;
           }
         }
         if(strip != 0) {

           float bxFloat = (comparatorTime-theTimingOffset)/theBunchSpacing
                           + theComparatorTimeBinOffset + theOffsetOfBxZero;


      // Comparator digi as of Nov-2006 adapted to real data: time word has 16 bits with set bit
      // flagging appropriate bunch crossing, and bx 0 corresponding to 9th bit i.e.

      //      1st bit set (bit 0) <-> bx -9
      //      2nd              1  <-> bx -8
      //      ...           ...       ....
      //      8th              9  <-> bx  0
      //      9th             10  <-> bx +1
      //      ...           ...       ....
      //     16th             15  <-> bx +6

      // Parameter theOffsetOfBxZero = 9 @@WARNING! This offset may be changed (hardware)!

           int timeWord = 0; // and this will remain if too early or late
           if ( (bxFloat>= 0) && (bxFloat<16) ) 
           timeWord = (1 << static_cast<int>(bxFloat) ); // set appropriate bit

           CSCComparatorDigi newDigi(strip, output, timeWord);
           result.push_back(newDigi);
         }

         // wait for the comparator to reset
         time += theComparatorDeadTime;
         // really should be zero, but strip signal doesn't go negative yet
         float resetThreshold = 1;
         while(time < theSignalStopTime
            && mainSignal->getValue(time) > resetThreshold) {
           time += theComparatorSamplingTime;
         }

       } // if over threshold
    } // loop over time samples
  }  // loop over comparators  
  // sort by time
  sort(result.begin(), result.end());
}


std::list<int> 
CSCStripElectronicsSim::getKeyStrips(const std::vector<CSCComparatorDigi> & comparators) const
{
  std::list<int> result;
  for(std::vector<CSCComparatorDigi>::const_iterator compItr = comparators.begin();
      compItr != comparators.end(); ++compItr)
  {
    if(std::abs(compItr->getTimeBin()-theOffsetOfBxZero) <= 2)
    {
      result.push_back(compItr->getStrip());
    }
  }
  // need sort for unique to work.
  result.sort();
  result.unique();
  return result;
}


std::list<int>
CSCStripElectronicsSim::getKeyStripsFromMC() const
{
  // assumes the detector hit map is filled
  std::list<int> result;
  transform(theDetectorHitMap.begin(), theDetectorHitMap.end(), 
            back_inserter(result), boost::bind(&DetectorHitMap::value_type::first,_1));
  result.sort();
  result.unique();
  return result;
}


std::list<int> 
CSCStripElectronicsSim::channelsToRead(const std::list<int> & keyStrips, int window) const
{
  std::list<int> result;
  std::list<int>::const_iterator keyStripItr = keyStrips.begin();
  if(doSuppression_)
  {
    for( ; keyStripItr != keyStrips.end(); ++keyStripItr)
    { 
      // pick the five strips around the comparator
      for(int istrip = (*keyStripItr)-window; istrip <= (*keyStripItr)+window; ++istrip)
      {
        if(istrip>0 && istrip<= nElements)
        {
          result.push_back(readoutElement(istrip));
        }
      }
    }
    result.sort();
    result.unique();
  }
  else 
  {
    // read the whole CFEB, 16 strips
    std::list<int> cfebsToRead;
    for( ; keyStripItr != keyStrips.end(); ++keyStripItr)
    {
      int cfeb = (readoutElement(*keyStripItr)-1)/16;
      cfebsToRead.push_back(cfeb);
      int remainder = (readoutElement(*keyStripItr)-1)%16;
      // if we're within 3 strips of an edge, take neighboring CFEB, too
      if(remainder < window && cfeb != 0)
      {
        cfebsToRead.push_back(cfeb-1);
      }
      // the 'readouElement' makes it so that ME1/1 has just one CFEB
      int maxCFEBs = readoutElement(nElements)/16 - 1;
      if(remainder >= 16-window && cfeb != maxCFEBs)
      {
        cfebsToRead.push_back(cfeb+1);
      }
    }
    cfebsToRead.sort();
    cfebsToRead.unique();

    // now convert the CFEBS to strips
    for(std::list<int>::const_iterator cfebItr = cfebsToRead.begin();
        cfebItr != cfebsToRead.end(); ++cfebItr)
    {
      for(int i = 1; i <= 16; ++i)
      {
        result.push_back((*cfebItr)*16 + i);
      }
    }
  }
  return result;
}
       

   

bool SortSignalsByTotal(const CSCAnalogSignal & s1,
                        const CSCAnalogSignal & s2) {
  return ( s1.getTotal() > s2.getTotal() );
}


void CSCStripElectronicsSim::fillDigis(CSCStripDigiCollection & digis, 
                                       CSCComparatorDigiCollection & comparators,
                                       CLHEP::HepRandomEngine* engine)
{
  if(doCrosstalk_) {
    addCrosstalk(engine);
  } 

  std::vector<CSCComparatorDigi> comparatorOutputs;
  runComparator(comparatorOutputs, engine);
  // copy these to the result
  if(!comparatorOutputs.empty())
  {
    CSCComparatorDigiCollection::Range range(comparatorOutputs.begin(), 
                                             comparatorOutputs.end());
    comparators.put(range, layerId());
  }

  //std::list<int> keyStrips = getKeyStrips(comparatorOutputs);
  std::list<int> keyStrips = getKeyStripsFromMC();
  fillStripDigis(keyStrips, digis, engine);
}


void CSCStripElectronicsSim::fillStripDigis(const std::list<int> & keyStrips,
                                            CSCStripDigiCollection & digis,
                                            CLHEP::HepRandomEngine* engine)
{
  std::list<int> stripsToDo = channelsToRead(keyStrips, 3);
  std::vector<CSCStripDigi> stripDigis;
  stripDigis.reserve(stripsToDo.size());
  for(std::list<int>::const_iterator stripItr = stripsToDo.begin();
      stripItr != stripsToDo.end(); ++stripItr)
  {
    createDigi( *stripItr, find(*stripItr, engine), stripDigis, engine);
  }

  CSCStripDigiCollection::Range stripRange(stripDigis.begin(), stripDigis.end());
  digis.put(stripRange, layerId());
}

 
void CSCStripElectronicsSim::addCrosstalk(CLHEP::HepRandomEngine* engine) {
  // this is needed so we can add a noise signal to the map
  // without messing up any iterators
  std::vector<CSCAnalogSignal> realSignals;
  realSignals.reserve(theSignalMap.size());
  CSCSignalMap::iterator mapI = theSignalMap.begin(), mapEnd = theSignalMap.end();
  for( ; mapI != mapEnd; ++mapI) {
    realSignals.push_back((*mapI).second);
  }
  sort(realSignals.begin(), realSignals.end(), SortSignalsByTotal);
  std::vector<CSCAnalogSignal>::iterator realSignalItr = realSignals.begin(),
                                         realSignalsEnd = realSignals.end();
  for( ; realSignalItr != realSignalsEnd;  ++realSignalItr)
  {
    int thisStrip = (*realSignalItr).getElement();
    // add it to each neighbor
    if(thisStrip > 1) {
      int otherStrip = thisStrip - 1;
      addCrosstalk(*realSignalItr, thisStrip, otherStrip, engine);
    }
    if(thisStrip < nElements) {
      int otherStrip = thisStrip + 1;
      addCrosstalk(*realSignalItr, thisStrip, otherStrip, engine);
    }
  }
}


void CSCStripElectronicsSim::addCrosstalk(const CSCAnalogSignal & signal,
                                          int thisStrip, int otherStrip,
                                          CLHEP::HepRandomEngine* engine)
{
  float capacitiveCrosstalk, resistiveCrosstalk;
  bool leftRight = (otherStrip > thisStrip);
  theStripConditions->crosstalk(layerId(), thisStrip, 
                                theLayerGeometry->length(), leftRight,
                                capacitiveCrosstalk, resistiveCrosstalk);
  theCrosstalkGenerator->setParameters(capacitiveCrosstalk, 0., resistiveCrosstalk);
  CSCAnalogSignal crosstalkSignal( theCrosstalkGenerator->getCrosstalk(signal) );
  find(readoutElement(otherStrip), engine).superimpose(crosstalkSignal);

  // Now subtract the crosstalk signal from the original signal
  crosstalkSignal *= -1.;
  find(thisStrip, engine).superimpose(crosstalkSignal);

}


void CSCStripElectronicsSim::createDigi(int channel, const CSCAnalogSignal & signal, std::vector<CSCStripDigi> & result,
                                        CLHEP::HepRandomEngine* engine)
{
  // fill in the sca information
  std::vector<int> scaCounts(nScaBins_);

  float pedestal = theStripConditions->pedestal(layerId(), channel);
  float gain = theStripConditions->smearedGain(layerId(), channel, engine);
  int chamberType = theSpecs->chamberType();
  float timeSmearing = CLHEP::RandGaussQ::shoot(engine) * theTimingCalibrationError[chamberType];
  // undo the correction for TOF, instead, using some nominal
  // value from ME2/1
  float t0 = theSignalStartTime+theSCATimingOffsets[chamberType] + timeSmearing
           + 29. - theAverageTimeOfFlight;
  for(int scaBin = 0; scaBin < nScaBins_; ++scaBin) {
    float t = t0 + scaBin*sca_time_bin_size;
    scaCounts[scaBin] = static_cast< int >
      ( pedestal + signal.getValue(t) * gain );
  }
  CSCStripDigi newDigi(channel, scaCounts);

  // do saturation of 12-bit ADC
  doSaturation(newDigi);

  result.push_back(newDigi);
  addLinks(channelIndex(channel));
  LogTrace("CSCStripElectronicsSim") << newDigi;
}


void CSCStripElectronicsSim::doSaturation(CSCStripDigi & digi)
{
  std::vector<int> scaCounts(digi.getADCCounts());
  for(unsigned scaBin = 0; scaBin < scaCounts.size(); ++scaBin) {
    scaCounts[scaBin] = std::min(scaCounts[scaBin], 4095);
  }
  digi.setADCCounts(scaCounts);
}


void CSCStripElectronicsSim::fillMissingLayer(const CSCLayer * layer,
                                              const CSCComparatorDigiCollection & comparators,
                                              CSCStripDigiCollection & digis,
                                              CLHEP::HepRandomEngine* engine)
{
  theSignalMap.clear();
  setLayer(layer);
  CSCDetId chamberId(theLayerId.chamberId());
  // find all comparator key strips in this chamber
  std::list<int> chamberKeyStrips;
  for(CSCComparatorDigiCollection::DigiRangeIterator comparatorItr = comparators.begin();
      comparatorItr != comparators.end(); ++comparatorItr)
  {
    // could be more efficient
    if(CSCDetId((*comparatorItr).first).chamberId() == chamberId)
    {
      std::vector<CSCComparatorDigi> layerComparators((*comparatorItr).second.first, (*comparatorItr).second.second);
      std::list<int> layerKeyStrips = getKeyStrips(layerComparators);
      chamberKeyStrips.insert(chamberKeyStrips.end(), layerKeyStrips.begin(), layerKeyStrips.end());
    }
  }
  chamberKeyStrips.sort();
  chamberKeyStrips.unique();
  fillStripDigis(chamberKeyStrips, digis, engine);
}
    

void CSCStripElectronicsSim::selfTest() const
{
  // make sure the zero suppression algorithms work
  std::list<int> keyStrips, stripsRead;
  // 
  bool isGanged = (readoutElement(nElements) == 16);
  keyStrips.push_back(readoutElement(19));
  keyStrips.push_back(readoutElement(30));
  keyStrips.push_back(readoutElement(32)); 
  stripsRead = channelsToRead(keyStrips, 3);
  if(doSuppression_)
  {
    unsigned int expectedSize = isGanged ? 10 : 12;
    assert(stripsRead.size() == expectedSize);
    assert(stripsRead.front() == readoutElement(17));
  }
  else 
  {
    unsigned int expectedSize = isGanged ? 16 : 48;
    assert(stripsRead.size() == expectedSize);
    assert(stripsRead.front() == 1);
  }
}