A method to minimize common rail pressure irregularities due to aliasing effect on battery voltage monitoring in a digital electronic control unit that is capable of PWM (Pulse Width Modulation) regulations of a metering valve unit in a diesel common-rail power-train system. At least an engine rotary speed signal is detected and at least a battery voltage signal is monitored, the method includes, but is not limited to calculating the aliasing frequency on said battery voltage signal as a function of said engine rotary speed signal, filtering the battery voltage signal before it is input to said controller module with at least one digital non-linear notch filter, the at least one digital non-linear notch filter centered about the first harmonic of the aliasing frequency, and input the filtered battery voltage signal, at least with the engine rotary speed signal, to the controller module for PWM regulating the metering valve unit.