A system (100) for determining a relative position of a secondary gear (12) includes a gear assembly (10) including a phonic wheel (13) fixed to a primary gear (11) and a secondary gear (12) rotatably engaged to the first gear, a sensor (20) configured to output a signal upon detecting a tooth (14) of the phonic wheel, and a digital logic circuit (30) configured to detect a revolution of the phonic wheel, to generate a primary gear tooth pulse at intervals corresponding to intervals of teeth (15) of the primary gear based on the detected revolution of the phonic wheel, and to generate a secondary gear revolution signal at an interval corresponding to a revolution of the secondary gear (12) based on the primary gear tooth pulse.