he autoregressive moving average (ARMA) solution is derived for the rhodium self-powered neutron detector inverse dynamics. Numerical performance is compared to the autoregressive (AR) inverse dynamics form. A potential difference in the dynamic range of the two methods would be masked by analog-to-digital converter quantizing noise. TheAR and ARMA inverse dynamics methods have equal performance for additive noise and require the same number of multiplications and additions per time step.