Hello AmandaCurlett,
you can simulate FIR, IIR filters and other digital signal processing application, passing from the continuous frequency domain of the Laplace transform to the discrete time domain of the Z transform. For example apply the Z-transform to the difference equation of a digital filter and find the transfer function H(z).
In PSpice the quickest way to implement this simulation is with a Laplace part, where specify the numerator and denominator of H(z), replacing z with exp(s*T), and a PARAM part that defines the relationship between the sampling frequency and the sampling period. I’ve uploaded a IIR second order filter example.