The smallest area of a television picture capable of being delineated by an electric signal passed through the system or part thereof. Note: It has three important properties, namely Pv, the vertical height of the picture element; Ph, the horizontal length of the picture element; and Pa, the aspect ratio of the picture element. In an analogue system Pv = 1/N, where N is the number of active scanning lines in the raster, Ph = trA/tc, where tr is the average value of the rise and delay times (10% to 90%) of the most rapid transition that can pass through the system or part thereof, tc is the duration of the part of a scanning line that carries picture information, and A is the aspect ratio of the picture.