line doubler: line doubler. Electronic component of an image processor that doubles the number of lines projected by the cathode ray tube. Explanation: The normal 50 Hz video image is displayed in the interlaced scanning displayed, ie only every second is displayed at a time row described, next the one in between, etc. With a relatively small television set, this is not noticeable to the eye, or is perceived at most as a slight flickering. On a large projected screen, the skipped lines show up as dark stripes because the relative speed of the electron beam decreases with the size of the screen.
Flickering is perceived more strongly for the same reason. The line doubler doubles the standard speed of the electron beam from 15,1 kHz to 32,2 kHz and thus enables sequential writing line by line, ie all pixels are written simultaneously at a given point in time. Linedoubling is the first requirement for a well-projected video image.