An impulse radio system estimates a separation distance between an impulse radio transmitter and an impulse radio receiver. The heel unit is slidingly associated with the toe unit through sliders and a fastener constituted by a screw is adapted to adjust and lock the mutual axial position of the heel unit with respect of the toe unit. The row of registration marks extends in a cross-process direction transverse to the process direction. The controller 230 sends a switch-back request 340, and the optical switch 160 switches from the second transmission line 130 to the first transmission line 120. The invention further relates to a device for forming said sole.