HIGH-ACCURACY FIT OF THE POLES OF SPECTROSCOPY AMPLIFIERS DESIGNED FOR MIXED ANALOG-DIGITAL FILTERING

In this paper, a method for the identification of the poles' and zeros ' position of an analog amplifier for nuclear spectroscopy used as a p refilter for a subsequent digital filter setup is presented, The propo sed technique is based upon a subspace-based system state-space identi fication (4SID) method, which is well suited to a data set constituted by a noisy measurement of the sampled impulse response of the circuit , The algorithm runs unassisted and does not require skills by the ope rator, The experiments confirm that by using the so-obtained pole valu es, the shape of the impulse response of the amplifier can be fit with much better than 1% accuracy. Consequently, the overall filtering (an alog + digital) can have finite duration and a top with a flatness muc h better than 1%.