Tubular connections and methods of designing tubular connections having selected rootcrest clearance when the box member and pin member are made-up. Thereby, a passage for the actual airbag of the passenger airbag module is cleared. In accordance with the relationship, variation components, which are contained in the unprocessed binding quantity data, are calculated. , so as to protect a human lift from the poisonous gas and safely escape from a critical region. The time dither clock reduction circuit receives the modulated signal and provides the feedback signal to the modulator.