| 摘要 |
A vector generator having a digital input and a cathode ray tube (CRT) display output is disclosed. Digital values specifying the initial point of the line segment in Cartesian coordinates are converted to proportional voltages applied across the capacitors of two identical resistance-capacitance networks which control the positioning of the CRT beam. A second pair of digital values defining the length and direction of the line segment with respect to the initial point are normalized digitally by left shifts until the larger of the pair equals or exceeds a normalization constant. The normalized values are added to the initial point coordinates, and the sums are then converted to proportional voltages applied to the resistors of the two networks. Simultaneously, a timer preset during the normalization operation is started and the CRT beam is turned on to start the drawing of the line segment. As a result of the normalization, the voltages applied to the RC networks are larger than needed to draw the segment. Consequently, the beam will be turned off by the timer well before the outputs of the RC networks reach the applied voltages. Thus, line segments of widely differing lengths are drawn at a normalized fast rate and are displayed at a normalized uniform visual intensity on the CRT.
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