Fast trigger logic with digitized time information
  We present a method for the evaluation, at the first level of trigger, of logical conditions with high time resolution, using the digitized times of fast signals delivered in the detectors of high rate experiments. We describe a dead-time-less implementation of this method on a commercial Field Programmable Gate Array (FPGA). By virtue of its features, the method offers an excellent solution to the problem of including veto conditions in the first level of trigger for experiments on rare decays. 
E. Imbergamo, A. Nappi, A. Papi, A. Riccini, M. Valdata