Investigations of the dynamic compression principle for fast detector pulses

Abstract

For detectors at LHC, fast and accurate data acquisition systems are required. The method of analog dynamic range compression in order to overcome the technological limits of quantization circuits is presented and shown for an application at the electromagnetic calorimeter (ECAL) for CMS. A model of the detector pulses and an analysis of the compressed pulses in time and frequency domain is given. As a consequence the demands on the electronics are derived. A method to specify the bandwidth and the slew rate requirements for the very front end electronics is presented. For nonlinear circuits approximated by piecewise-linear circuits a detailed analysis is worked out and applied to the dynamic range compressor. This work is meant to be a guideline to determine bandwidth requirements also for other topologies and should help to optimize overall system performance.