A system utilizing coarse and fine position-measuring elements simultaneously in remote-position-control servo mechanisms

A system is described where both the coarse and the fine measuring elements normally employed in a high-precision position-control servo mechanism can be used simultaneously without the need for switching from coarse to fine. The steady-state accuracy of the whole mechanism is the same as that of a conventional coarse-fine changeover system. The stability of the new system is sensibly that which would be obtained using only the coarse measuring elements.