Video disc encoding and decoding system providing intra-field track error correction
AssigneeRCA Corporation
InventorsWalter G. Gibson, Michael A. Plotnick, Thomas Y. Chen
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Abstract
Video disc track numbers are conveyed during each video line by means of a quadrature phase shift keyed data carrier recorded along with the picture and sound carriers on a video disc. Upon playback, the data sequence is processed to identify tracking errors occurring within each video field to thereby enable immediate correction of disc tracking errors on a line-by-line basis thus minimizing picture and sound interruption caused by intra-field tracking errors.
Claims4
A method for forming a video disc recording signal for facilitating intra-field track error correction upon subsequent playback of disc records recorded with said disc recording signal comprising the steps of:
- (a) providing a video signal inclusive of a data sequence representative of field numbers of said video signal;
- (b) providing a subset of said data sequence representative of track identification numbers;
- (c) encoding said subset of said track identification numbers by quadrature phase shift keying a carrier wave;
- (d) frequency modulating a second carrier wave with said video signal;
- (e) combining said quadrature phase shift keyed carrier wave with said frequency modulated carrier wave to form said disc recording signal.
A video disc player for use with video disc records recorded with a signal manifestation including a video signal inclusive of a first data component representative of video field numbers and a quadrature phase shift keyed carrier wave haivng four signaling intervals per line of said video signal, the first interval conveying a reference phase component, the remaining signaling intervals conveying a subset of said video field numbers corresponding to a track identification number repeated within each field of said video signal, comprising:
- (a) recovery means for recovering said first data sequence from said recorded signal manifestation;
- (b) quadrature phase shift keyed demodulator means responsive to said reference phase component for demodulating said subset of said video field numbers;
- (c) data register means for storing said demodulated subset of said video field numbers;
- (d) data processing means for comparing said subset of said video field numbers with said first data sequence for developing an intra-field track error correction signal;
- and
- (e) means for applying said intra-field track error correction signal to said recovery means in a sense to reduce tracking errors occurring with a field of said video signal.
Dependencies are inferred from the claim text.