The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 25, 1995
Filed:
Dec. 27, 1993
Alfonsus M Van Amesfoort, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
Known display devices include a video signal processing circuit with a black level setting circuit. This black level setting circuit measures the black level of the video signal, for example, during the field retrace interval by making use of an extra output of the video output stage. However, the measured black level has a line-frequency interference component which is caused by a parasitic capacitance in the display tube. The line-frequency interference component is fully compensated for by coupling one side of a secondary winding of a transformer, required for the focusing voltage to be generated, to a first capacitor, the other terminal of which is connected to the measuring input of the black level setting circuit, and by coupling at least a second and a third capacitor across the secondary winding of the transformer.