EP0152142A2
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EP
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Method for reproducing information from an optically readable record carrier and apparatus for use in said method
Assignee: Koninklijke Philips NV
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Filing: 1985-02-07
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Granted: —
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Expires: 2005-02-07
Abstract
Abstract A Compact-Disc-Digital-Audio-System is described in which the bandwidth is reduced in order to extend the playing time, for example for the reproduction of 10 hours of speech. This is achieved without significantly modifying the existing players and without affecting the standard EFM coding, by multiplexing a plurality of channels in such a way that they can be reproduced consecutively by repeatedly playing the entire CD disc.
Inventors
- 👤 Eric Christian Schylander
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 12:30
CPC Classifications
G; G11; G11B; G11B17/00; G11B17/005; G11B20/00; G11B20/10; G11B20/10527; G11B20/12; G11B20/1217; G11B20/1251; G11B7/00; G11B7/004; G11B7/005; G11B2220/00; G11B2220/20; G11B2220/25; G11B2220/2537; G11B2220/2545
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
94 words
A system of reproducing information from an optically readable record carrier on which said information is recorded in the form of an encoded series of digital signal samples which are recovered by decoding after read-out, characterized in that N information channels are multiplexed on said record carrier in such a way that each time N consecutive samples are associated with N different information channels and said N information channels can be reproduced one by one by playing the entire record carrier N times, each time under selection of the samples associated with said channel.
Claim 2
Independent Claim
94 words
A system of reproducing information from an optically readable record carrier on which said information is recorded in the form of an encoded series of digital signal samples which are recovered by decoding after read-out, characterized in that N information channels are multiplexed on said record carrier in such a way that each time N consecutive samples are associated with N different information channels and said N information channels can be reproduced one by one by playing the entire record carrier N times, each time under selection of the samples associated with said channel.
Claim 3
Dependent Claim
66 words
A system as claimed in Claim 1, characterized in that each time at least one bit of the digital samples is used as a synchronising bit in such a way that during the consecutive read-out of said samples the sequence of said bits results in a synchronising signal which is used for synchronising the selection of the samples associated with the channel to be reproduced instantaneously.
Claim 4
Dependent Claim
23 words
A system as claimed in Claim 2, characterized in that the least significant bit of said samples is selected as the synchronising bit.
Claim 5
Dependent Claim
87 words
An apparatus for use in the system as claimed in Claim 1, 2 or 3, which apparatus comprises a read device, a decoding circuit, and a read-control circuit, characterized in that the apparatus comprises selection means for selecting a specific sample from every N samples being reproduced and the control means are constructed to repeatedly play the record carrier and, after every scan to advance a channel counter which controls the selection means in such a way that the samples associated with the relevant channel are selected.
Claim 6
Dependent Claim
28 words
An apparatus as claimed in Claim 4, characterized in that the apparatus comprises means for extracting synchronising bits from the decoded signal samples for synchronising the selection means,
Claim 7
Dependent Claim
91 words
An apparatus as claimed in Claim 4 or 5, in which the decoding circuit is constructed to supply two digital signal samples at the same time, characterized in that the selection means comprise first switching means for selecting one of said two simultaneously supplied signal samples as a function of the count of the channel counter, and second switching means for selecting a specific sample of every i N samples reproduced via the first switching means as a function of the count of the channel counter, N being an even integer.
Claim 8
Dependent Claim
18 words
An apparatus as claimed in Claim 4, 5 or 6, characterized by controls for presetting the channel counter.
Claim 9
Dependent Claim
57 words
A record carrier for use in a system as claimed in Claim 1, 2 or 3, characterized in that N information channels are multiplexed on the record carrier in such a way that they can be reproduced consecutively by repeatedly playing said record carrier under selection of the signal samples associated with the channel to be reproduced.
Claim 10
Dependent Claim
39 words
A system as claimed in Claim 1, 2,or 3, characterized in that there is provided a storage circuit for storing the playing position reached when reproduction is interrupted for automatically starting reproduction at said position when playing is continued.
Claim 11
Dependent Claim
77 words
An apparatus for use in the system as claimed in Claim 9, characterized in that the apparatus comprises a storage circuit, means for storing an identification code of the record carrier being played, the reproducing position, and the channel being reproduced, and means for presetting said apparatus in such a way that when playing is restarted after read out of the identification code reproduction is continued at the position where it has been interrupted the last time.
References Cited (Backward Citations)
No citation records indexed.
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