FIELD: video systems such as video monitors. SUBSTANCE: since data on electrical characteristics of video system are set in advance, irrespective of input of any external data, single input of parameters by user or choice of automatic control mode results in comparison of newly introduced external data with preset data, and image vertical and horizontal dimensions are automatically controlled in video system. Image-size automatic-control device has microcomputer, analog-to-digital converter, and means for controlling image vertical and horizontal dimensions. EFFECT: facilitated control, reduced cost. 5 cl, 3 dwg
