Abstract: The object of the present invention is to easily compensate automatic brightness limiting performance and automatic contrast limiting performance even if a picture is displayed with a different aspect ratio and to prevent deterioration of picture quality such as gradation and sharpness.

Abstract: A ghost cancelling system which distinguishes whether ghosts have been substantially cancelled from a video signal for finding an equilibrium condition. The system calculates a specified value which depends on the noise signal contained in the video signal. The tap coefficients which are equal or greater than the specified value are then detected, and the system corrects only those tap coefficients after the equilibrium condition exists.

Abstract: In a mixer in which several video signal inputs are multiplied by respective mixing factor signals and the multiplier outputs are added together to produce an output video signal, one of the video inputs is given priority and the mixing factors for the other video inputs are premultiplied by a second set of multipliers in such a manner that the video input of next priority will not have an amplitude greater than what is "left over" by the higher priority signal, and so on in descending order of priority. For further flexibility it is useful to provide a third set of multipliers to allow more external control inputs to participate in determining mixing factors and facilitate special effects. A multiplier of the third set is not necessary for control of the mixing factor of the video input of lowest priority. Even a multiplier of the second set is not strictly necessary for that lowest priority video input.