Abstract: An analog to digital shaft position digitizer including a pair of driven members where one member with "fine" reference intelligence and increment intelligence thereon is driven at a higher speed than the other member with "coarse" reference intelligence and transfer command intelligence thereon. A photo-optic sensor system picks up the intelligence from the members and by an electronic gating circuit the "fine" and "coarse" reference intelligence pulses are sent to a digital counter to reset the counter while increment intelligence pulses are sent to a clocking line of the counter to provide parallel binary numbers. Transfer command intelligence pulses from the low speed member transfers the parallel binary numbers from the digital counter to an electronic latching circuit to indicate shaft angle displacement of a rotating shaft.