Digital beam position measurement at GSI-SIS and CERN-PS

New, digital beam position measurement techniques needed in hadron machines, accelerating beams with fast varying frequencies, are to be presented. The role of analog electronics is reduced to signal amplification and attenuation as well as bandwidth limitation. This paper explores approaches for the position evaluation of acquired signals, suggesting systems for 'free running' estimation as well as machine timing dependent methods. For accurate determining of the transversal bunch position, a good integration window estimation is needed. Two filtering methods will be introduced for this purpose, median and FFT (fast Fourier transform) filtering, both methods detecting peaks at bunch signal starting and ending points. (authors)