An apparatus displays a video signal (VID) by means of a scan (SCAN). The apparatus
may be, for example, a television set. The apparatus comprises a device (SCAVEM)
for modulating the scanning rate (Vscan) as a function of the derivative (DLUM)
of a luminance signal (LUM) extracted from the video signal (VID). This enables
the subjective display quality to be improved. The apparatus has the following
characteristic feature in order to obtain an even better quality, notably when
the apparatus is used for displaying video signals of different types. The derivative
(DLUM) of the luminance signal, as a function of which the scanning rate (Vscan)
is modulated, is obtained by means of a difterentiator circuit (DIFF) having a
controllable frequency response (CFR).