ELECTRONIC COORDINATE POSITION DIGITIZING SYSTEM

摘要

An electronic position measuring system is disclosed for use in a digitizer of the type which converts analog information in graphical form to digital information. The system provides small scale or fine measurement by means of a polyphase grid winding with pulsed polyphase excitation. A cursor is movable over the grid winding and develops a position signal which has a phase angle corresponding to the position within a grid cycle. Phase angle measuring means are provided to derive the position information. The system also includes a large scale or coarse measurement grid comprising plural parallel conductors with at least one conductor per grid cycle. Excitation means are provided for sequentially pulsing the conductors and means connected with the cursor develop a stop signal in response to pulsing of the conductor nearest the cursor. A position counter counts the excitation pulses until the stop signal occurs and thus registers a count corresponding to the position of the cursor. The polyphase grid winding is provided with phase windings having plural distributed conductors per pole to produce an approximately sinusoidal distribution of magnetic flux over each pole of the winding to increase the accuracy of position measurement.