Cathode ray tube image position correction for radar displays - reduces acceleration voltage to low voltage value, transferred to digital form and applies correction value to offset circuits

摘要

The high voltage acceleration voltage (Vtht) of the Cathode Ray Tube is sensed and a proportional low voltage produced in an electrical circuit (30). The voltage is digitised (40) and the square root taken and compared with a reference value (41). Correction terms (42,43) are then applied to the horizontal and vertical Cathode Ray Tube electrical circuits (10,20), producing the corrected position of the display on the Cathode Ray Tube. ADVANTAGE- Allows image positions on screen to be corrected when brightness values are varying rapidly.