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:
Aug. 04, 1981
Filed:
May. 25, 1979
Peter Bragas, Hildesheim-Itzum, DE;
Blaupunkt-Werke GmbH, Hildesheim, DE;
Abstract
An NTSC color television signal picked up from a disc recording is mixed in such a way as to provide one sideband having the chrominance carrier at the standard frequency and another sideband at a higher frequency which can be stepped down in a second mixer to the color-carrier frequency to provide a side band shifted 180.degree. in phase with respect to the color signal provided by the lower sideband of the first mixer. The mixing frequencies are kept in step by utilizing a standard frequency generator at the color-carrier frequency which controls the phase of a VCO supplying a first mixing frequency in a third mixer from the output of which the second harmonic of the difference frequency is selected as the mixing frequency for the second mixer. From the standard frequency output there are also derived the phase-shifted color burst pulses for identifying the two chrominance signals produced as they are alternately utilized for the output signal. A delay of one line scanning period allows the use of the delayed and undelayed signals to give the effect of a comb filter for the luminance signals and for the chrominance signal, and the delay line is also used in connection with a video switch and disturbance detector to allow use of the last undisturbed line when an unusable line is detected. The playback speed is slightly reduced (cf. U.S. Pat. No. 4,148,077) for reproduction by a television receiver operating at the European line-scanning frequency.