Television signal recording/reproducing apparatus and method with DC shifter
AssigneeSony Corporation
InventorsKeiji Kanota, Naofumi Yanagihara
Life of this patent
Estimating the term…
Abstract
Recording and reproducing a television signal with a DC shifter prevents compression distortion of a PAL plus television signal. The PAL plus television signal includes a vertical resolution signal for enhancing vertical resolution which vertical resolution signal is included in the same compression blocks as some of the component video signals. Such compression blocks are shifted to a DC set up value so that the signals within those compression blocks do not have varying DC offsets which otherwise could result in compression distortion. Similarly, upon reproduction, the DC set up value is removed after decompression and the original television signal is restored with complete vertical resolution.
Claims16
An apparatus for reproducing from a record medium a digital signal representing a video image and including a vertical resolution signal and a component video signal, the digital signal being in the form of compression blocks with at least some compression blocks including both said vertical resolution signal and said component video signal, wherein said vertical resolution signal included in said compression blocks are DC shifted from varying DC offsets to a DC setup value thereby preventing compression distortion resulting from compression of signals of varying DC offsets within said compression blocks, said apparatus comprising:
- means for reproducing said compression blocks from said record medium;
- and
- means for DC shifting said vertical resolution signal of said compression blocks, shifted to said DC set up value so as to prevent said compression distortion, to said varying DC offsets such that said DC set up value is removed.
A method for reproducing from a record medium a digital signal representing a video image and including a vertical resolution signal and a component video signal, the digital signal being in the form of compression blocks with at least some compression blocks including both said vertical resolution signal and said component video signal, wherein said vertical resolution signal included in said compression blocks are DC shifted from varying DC offsets to a DC setup value thereby preventing compression distortion resulting from compression of signals of varying DC offsets within said compression blocks, said method comprising the steps of:
- reproducing said compression blocks from said record medium;
- and
- DC shifting said vertical resolution signal of said compression blocks, shifted before compression to said DC set up value so as to prevent said compression distortion, to said varying DC offsets such that said DC set up value is removed.
Dependencies are inferred from the claim text.