Fig. 1. Transfer function model of peak pulse shaping

Fig. 2. Definition of the shape of a flat-top peaking pulse and its derivatives (a) Shape of the pulse h(n), where na=10, nb=20, nc=30, (b) First derivative h¹(n), (c) Second derivative h²(n), (d) Third derivative h³(n)

Fig. 3. Parameter settings for flat-top peaking pulse shaping

Fig. 4. Photograph of experimental test setup

Fig. 5. Digital spectroscopy measurement system

Fig. 6. Different shaping filter effects under noise interference(a) Flat-top peaking pulse shaping, (b) Flat-top pulse shaping with a width of 0, (c) Triangular filter shaping

Fig. 7. Recognition performance of trapezoidal shaping and flat-top peaking shaping with the same rise time and shaping time under different pileup conditions: recognition performance at (a) Pileup level 0<l<nb, where n_a=40, nb=80 and n_c=200, (b) Pileup level l=nb, (c) Pileup level n_b<l<n_a+n_b (color online)

Fig. 8. Gaussian shaping stacking identification results

Fig. 9. Testing performance of FPGA-based digital spectroscopy system