IPFM model with absolute refractory period and modulation depth

A low-pass-filtering (LPF) method by French and Holden was improved to solve the truncation error and long computation time. The LPF method is useful to demodulate the generating function of an integral pulse frequency modulation (IPFM) model. However, in the case of large modulation depth pulses, the false components are produced in the higher frequency range even in the improved LPF method. Therefore, an integral function (IF) method was developed, which has higher accuracy and shorter calculation time than the improved LPF method. In this paper, the IF method is improved considering the absolute refractory period. Moreover, the improved IF method is calculated with changing the modulation depth of the IPFM model. As a conclusion, the demodulation error does not increase drastically by the increase of the refractory length from 0% to 50% of the mean impulse intervals.