Patent ID: 6515600
Filing Date: 2003-02-04
Classification: H04N

Abstract:
A circuit arrangement for regenerating a black level of video signals during analog-to-digital (A/D) conversion, in which a deviation of the black level of the digital video signals from a predetermined value influences the black level of the analog video signals, characterized in that the circuit arrangement comprises:an input for receiving analog video signals; an A/D converter coupled to the input for digitally converting the analog video signals; means for comparing scanning values obtained during A/D conversion of the black level of the analog video signals with the predetermined value thereby forming difference values, said comparing means performing the comparison during blanking intervals of the video signals; means for generating a ramp signal for tendency-compensating deviations in response to the difference values, said ramp signal extending through a line containing the blanking interval and a subsequent line; and means for superimposing the ramp signal on the analog video signals prior to application to said A/D converter.