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:
Nov. 01, 1988
Filed:
Aug. 25, 1986
Gerhard Gunter, Neuweiler-Agenbach, DE;
Hermannus Schat, Freiburg, DE;
Herbert Elmis, Denzlingen, DE;
Bernd Novotny, Gundelfingen, DE;
Otmar Kappeler, Neuenburg, DE;
Dietmar Ehrhardt, Freiburg, DE;
Deutsche ITT Industries GmbH, Freiburg, DE;
Abstract
The frequency conversion of an RF signal is performed by the 'third method' using a suitable frequency reversal which makes the frequencies of the picture carrier, the chrominance subcarrier, and at least one sound carrier appear transformed into the baseband, such that the frequencies of the transformed picture carrier and the transformed chrominance subcarrier coincide. Unavoidable differences in the signal paths of the frequency reversal result in a spurious signal which produces a temporally/locally varying moire on the screen. By means of a frequency offset, this spurious signal is transformed into a frequency range which is not found annoying by the observer, so that the moire becomes invisible. This frequency range is preferably the exact center region between two spectral lines of the horizontal frequency of the composite color signal in the baseband.