A new fast and programmable trigger logic

Abstract The NAl (FRAMM) experiment, under construction for the CERN-SPS North Area, deals with more than 1000 counter signals which have to be combined together in order to build sophisticated and highly selective triggers. These requirements have led to the development of a low cost, combinatorial, fast electronics which can replace, in an advantageous way, the standard NIM electronics at the trigger level. The essential performances of the basic circuit are: 1. 1) programmability of any desired logical expression; 2. 2) trigger time independent of the chosen expression; 3. 3) reduced cost and compactness due to the use of commercial RAMs, PROMs, and PLAs; 4. 4) short delay, less than 20 ns, between input and output pulses.