Abstract: A relative position transducer for determining the angular position of a first member angularly movable relative to a second member includes a coded track on the first member, a read head mounted on the second member, drive means for oscillating the read head to scan over and read a limited region of the coded track, and a microcomputer for interpreting the code read by the read head as the position. A first sensor detects when the read head is in a predetermined reference position and a second sensor detects the end points and direction of the read head scan. The sensor outputs are connected to the computer for correct interpretation of the read head output. An interplation is used to improve the accuracy of the position determination.