An improved polar co-ordinate digitizer where a cord is extensible from a base unit and moves a cord guide to provide an angle measurement and is also wrapped on a drum whose movement reflects a length measurement. The winding drum is mounted on a common center or shaft with the angle arm on which the cord guide is located. Both rotate separate disks which have their peripheries a bar-code pattern. These are above the drum and cord guide so as to allow unrestricted angular movement of the cord. Light-emitting diode and photo detector means sense the bar- patterns to provide length and angle parameters.
展开▼
