Results From A Neural Trigger Based On The Ma16 Microprocessor

Results from a neural-network trigger based on the digital MA16 chip of Siemens are reported. The neural trigger has been applied to data from the WA92 experiment, looking for beauty particles, which have been collected during a run in which a neural trigger module based on Intel's analog neural chip ETANN operated, as already reported. The MA16 has a precision of 16 bits for input variables, 16 bits for weights, 16 bits for scalar multipliers modifying the transfer function shape, 47 bits for thresholds, 53 bits for internal calculations, 38 bits for the output. Of the latter only 16 bits are used in the MA16 board, as input to the transfer function inplemented on 16-bit addressable EPROM's. The MA16 board operated at 50 MHz, yielding a response time for a 16 input variable net of 3 mu s for a Fisher discriminant (1-layer net) and of 6 mu s for a 2-layer net. Results are compared with those previously obtained with the ETANN trigger.