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:
Oct. 25, 1994
Filed:
Apr. 12, 1993
Gopal K Srivastava, Arlington Heights, IL (US);
Zenith Electronics Corporation, Glenview, IL (US);
Abstract
A line locked digital color demodulator separates the V and U color components and the burst signal and uses a ROM for providing phase shifts to the V and U demodulation axes. During the burst time of an NTSC signal, the color component axes are shifted by 45.degree. such that the burst signal produces equal components along the axes. A correction signal is developed in response to this shifting and is used in conjunction with a frequency error signal for continuously addressing the ROM. The error signal is developed by counting the number of clock pulses over a 16 line period and comparing the number counted with a standard number for the type signal being received. The error signal is combined with the correction signal for adjusting the phase of the V and U demodulation axes. For a signal, the burst is normalized to always be at 135.degree. and its components along the V and -U axes are compared as with the NTSC signal.