Digitalization of inverting filter shaping circuit for nuclear pulse signals

In the design of filter shaping circuits for nuclear pulse signals, inverting filter shaping circuits perform better than non-inverting filter shaping circuits. Because these circuits facilitate changing the phase of a pulse signal, they are widely used in processing nuclear pulse signals. In this study, the transfer functions of four types of inverting filter shaping circuits, namely the common inverting filter shaping, improved inverting filter shaping, multiple feedback low-pass filter shaping, and third-order multiple feedback low-pass filter shaping, in the Laplacian domain, are derived. We establish the numerical recursive function models and digitalize the four circuits, obtain the transfer functions in the Z domain, and analyze the filter performance and amplitude–frequency response characteristics in the frequency domain. Based on the actual nuclear pulse signal of the Si-PIN detector, we realize four types of inverting digital shaping. The results show that under the same shaping parameters, the common inverting digital shaping has better amplitude extraction characteristics, the third-order multiple feedback low-pass digital shaping has better noise suppression performance, and the multiple feedback digital shaping takes into account both pulse amplitude extraction and noise suppression performance.