Complex sentence: Vector displays are a now-obsolete alternative to raster scan displays, where the image is a grid of pixel spots and the CRT beam repeatedly sweeps the entire screen in a fixed horizontal pattern like a television, regardless of which dots are turned on.
Split into simpler sentences: Vector displays are a now-obsolete alternative to raster scan displays. In raster scan displays, like in TV sets, the image is a grid of pixel spots and the CRT beam repeatedly sweeps the entire screen in a fixed horizontal pattern, regardless of which dots are turned on.