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:
Sep. 19, 1995
Filed:
Aug. 30, 1994
Charles M White, Noblesville, IN (US);
Thomson Consumer Electronics, Inc., Indianapolis, IN (US);
Abstract
In a video display system including a cathode ray tube (CRT) as a display device and video output amplifiers for amplifying relatively low level red, green an blue video input voltages to produce respective relatively high level video output voltages suitable for application to the CRT, a 'black tracking' circuit is coupled to the inputs of video output amplifiers. Voltage to current converters are utilized as preamplifiers for the video output amplifiers. The 'black tracking' circuit includes terminating resistors connected at one end to respective outputs of the voltage to current converters for converting output currents of the converters to respective ones of the low level video input voltages, and a common resistor connected between the other ends of the terminating resistors and a signal ground point. A filter capacitor is connected in parallel with the common resistor. A common 'black tracking' voltage representative of the average picture level of a reproduced image is developed across the common resistor and, as a result of the connection to individual ones of the terminating resistors, is added to each one of the low level video input voltages at the inputs of respective ones of the video output amplifiers.