CIRCUIT FOR AUTOMATIC CONTRAST DECREASING DURING TELETEXT OR MONITOR REGIME

摘要

In a TV receiver responsive to either conventional television video signals or an auxiliary video signal representative of alphanumeric text or graphic information, to prevent undesired "blooming" of the display due to high kinescope beam currents when the alphanumeric text or graphics are displayed on the screen of a kinescope, means are provided for reducing at least one amplitude characteristic of the auxiliary video signal, such as its peak-to-peak signal level (contrast) so as to reduce the kinescope beam current whenever the alphanumeric text or graphics are displayed.