| 摘要 |
<p>ITERATIVE COORDINATE DATA APPROXIMATION SYSTEM FOR PHOTOEMISSIVE PIXEL PATTERN DISPLAYS Almost any Photoemissive Pixel Pattern Display Tube (PPDT) System, such as one for a PMDT matrix display system is capable of supplying an indication of coordinate data for input to data processing systems and the like with this electronic photoresponsive data approximation system. A photoresponsive probe with relatively large optical aperture stop is coupled to suitable electric current amplifying circuitry which in turn is coupled to data resolving circuitry for gating counting circuitry coupled to the display matrixing circuitry for determining the coordinates of the location of the probe in terms of the geometrical dimensions of the display. The probe is arranged for sensing a predetermined differential in photoemission as the cathode ray beam passes through the aperture stop. Conveniently, the aperture stop is circular and from the top the successive intercepted raster scans are longer up to the center of the stop. The electronic circuitry responsive to the probe is arranged for timing the beginning of each scan as intercepted. Upon timing the maximum duration of interception at the center of the aperture stop, one coordinate, y, is determined. The other coordinate, x, is then determined by averaging the time of beginning and the time of ending this central intercepted scan. Alternately, this x coordinate is determined by locating the central point of this central intercepted scan. The technique is applicable to polar coordinate (?,.theta.) data systems and to spiral and serpentine SA974047 -1-scan systems with only slightly more complex circuitry required. Variations in photoemissivity as the information is displayed are less effective in the determination than in the conventional systems and the approximation system is compatible with almost all photoemissive matrix display systems.</p> |
