A drill string having a drill bit with a bit body located between a shank and a working face. The working face has at least one cutting element and a jack element disposed partially within the drill bit body and partially protruding from the working face. The jack element is adapted to be rotated with respect to the bit body by a driving mechanism disposed within a bore of the drill string. A generator or motor with a rotor is incorporated into a torque transmitting mechanism that links the driving mechanism to the jack element, and configured so that at least one waveform is produced in the generator or motor when the jack element is rotated. The waveform is processed by an electronic processing device to determine the rotational position of the jack element.