Traces of a step input signal and the filtered output signal

where Si represents the values of the step input signal (either 0 or 1) and Yi represents the filtered values of the output signal.

Values of step input signal and Bessel filtered output signal for the first and second iteration cycle

By definition, the filter response time tF is the rise time of a filtered output signal between 10 % and 90 % on a step input signal.

In Figure a, the traces of a step input signal and Bessel filtered output signal as well as the response time of the Bessel filter (tF) are shown.