Trigger Simulation Overview (May 1997)
From the point of view of BaBar software, the Trigger simulation software is equivalent to digitization, running entirely in the reconstruction framework. Unlike other subsystem digitizations, Trigger does not only contribute DAQ event data, it also
contributes simulated Global Trigger decisions and Tzero as well as Fast Control System clocks.
Level 1
The trigger simulation (including the trgDC, trgEM, TrgSim, TrgData, FcsSim, and FcsData packages) has provided the detailed input to making the Level 1 Trigger electronics design. Engineering constraints have already been incorporated into the software
representations of the algorithms. The simulation is up to date at a very detailed level, including a complete simulation of the time domain and with overlay of simulated beam-induced backgrounds. Software filters (Level 3) are being studied to validate
the trigger architecture and aid design of the online farm.
Digitization outputs from the trigger simulation have been implemented on an as-needed basis; currently, the time of the Level 1 Accept and trigger word from the GLT (Global Level 1 Trigger), and DAQ data from the TSF (Track Segment Finder) boards are
finished. As DAQ information from other boards than the TSF in the trigger system is needed by users, simular interfaces will be created.
All of the trigger code works with either the trigger release, 2.1.0, or the latest and greatest releases (e.g. 4.1.1) although the latter is not routinely tested for functionality. Previously reported link order problems should go away since we now
use the standard link order mechanism (thanks to Steve Gowdy!). Users: Currently, the TrgDigi and TrgSimOut are used by the Level 3 packages, and the FcsSimOut is used by SvtSim and TrgSim.
Level 3
Level 3 algorithm software is still in the exploratory phase (L3Dch and L3Emc). Other pieces of Level 3 will evolve during 1997, with steering algorithms etc. |
