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EP0104700A1
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Method of recording a digital information signal on a record carrier, record carrier provided with such an information signal, and read/write apparatus for such a record carrier
Assignee: Koninklijke Philips NV
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Filing: 1983-09-16
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Granted: —
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Expires: 2003-09-16
Abstract
Abstract For a controlled positioning of the read element relative to the track to be read during the read-out of such a record carrier low-frequency tracking signals may be recorded in the tracks. Instead of adding separate tracking signals to the information signal, steps are taken, in accordance with the invention, that these tracking signals are represented by the d.c. content. During conversion of the information words of the information signal into channel words steps are therefore taken to provide two channel words whose d.c. content is equal but opposite for each information word. The choice between these two channel words is made depending on a control signal which depends on the desired tracking signal.
Inventors
- 👤 Martijn Hector Hendrik Höfelt
- 👤 Edmond De Niet
- 👤 Albert Maria Arnold Rijckaert
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 20:26
CPC Classifications
G; G11; G11B; G11B21/00; G11B21/02; G11B21/10; G11B15/00; G11B15/18; G11B15/46; G11B15/463; G11B20/00; G11B20/10; G11B20/14; G11B20/1403; G11B20/1423; G11B20/1426
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
190 words
A method of recording a digital information signal in information tracks of a record carrier, which method comprises the conversion of consecutive information words of the applied digital information signal into channel words of a selected channel code prior to recording, which channel code has been selected so that for each information word of the applied digital information signal a first and a second channel word are available, the first channel word forming part of a group of permissible channel words having a d.c. content unequal to zero and the second channel word being the complement of the first channel word, characterized in that for generating a tracking signal, comprising a carrier wave of comparatively low frequency relative to that of the recorded information signal and when recorded in the information tracks on the record carrier, is intended to provide information about the position of a read element relative to the information track to be scanned, in a direction transverse to the track direction, a binary control signal is generated, the choice from the two channel words available for each information word being made depending on said binary control signal.
Claim 2
Independent Claim
190 words
A method of recording a digital information signal in information tracks of a record carrier, which method comprises the conversion of consecutive information words of the applied digital information signal into channel words of a selected channel code prior to recording, which channel code has been selected so that for each information word of the applied digital information signal a first and a second channel word are available, the first channel word forming part of a group of permissible channel words having a d.c. content unequal to zero and the second channel word being the complement of the first channel word, characterized in that for generating a tracking signal, comprising a carrier wave of comparatively low frequency relative to that of the recorded information signal and when recorded in the information tracks on the record carrier, is intended to provide information about the position of a read element relative to the information track to be scanned, in a direction transverse to the track direction, a binary control signal is generated, the choice from the two channel words available for each information word being made depending on said binary control signal.
Claim 3
Dependent Claim
28 words
A method as claimed in Claim 1, characterized in that the first channel word forms part of a group of permissible channel words having the same d.c. content.
Claim 4
Dependent Claim
51 words
3 . A method as claimed in Claim 2, characterized in that the information words of m data bits of the information signal are converted in binary channel words of n data bits, where in which p is the prescribed number of data bits of a first type per channel word,
Claim 5
Dependent Claim
81 words
A method as claimed in Claim 1, characterized in that the first channel word forms part of a group of permissible channel words whose number of data bits is twice that of the information words of the information signal, each data bit being either preceded or followed by a data bit of the same value at least within that sequence of data bits of a channel word, which starts with the second data bit and ends with the penultimate data bit.
Claim 6
Dependent Claim
156 words
A method as claimed in Claim 4, in which the data bits of a channel word assume one of two possible values, characterized in that the group of permissible channel words comprises words whose first data bit is not followed by a data bit of the same value, for such a channel word a substitute channel word is available which also meets the requirements imposed on the permissible channel words but which contains a first data bit of a value which is complementary to the value of the first data bit of the associated channel word, and a choice is made, depending on the value of the last data bit of the preceding channel word and the control signal, between the channel word and the substitute channel word in such a way that the first data bit of the word being used has the same value as the last data bit of the preceding channel word.
Claim 7
Dependent Claim
151 words
A method as claimed in Claim 4, in which the data bits of a channel word assume one of two possible values, characterized in that the group of permissible channel words comprises words whose last data bit is not preceded by a data bit of the same value and for such a channelword a substitute channel word is available which also meets the requirements imposed on the permissible channel words but has a last data bit whose value is the complement of the value of the last data bit of the associated channel word, a choice being made, depending on the value of the first databit of the next channelword and the control signal, between the channel word and the substitute channel word in such a way that the last data bit of the word being used has the same value as the first data bit of the next channel word.
Claim 8
Dependent Claim
51 words
A method as claimed in Claim 6, characterized in that each word of the permissible channel words whose last data bit is not preceded by a data bit of the same value with a data bit having the same value as the first data bit of the corresponding substitute channel word.
Claim 9
Independent Claim
72 words
A method as claimed in any one of Claims 4 to 7, characterized in that at least all channel words which meet the criterion that each data bit is preceded or followed by a data bit of the same value and all channel words which, except for the first data bit, meet this criterion comprise a first data bit whose value corresponds to the first data bit of the associated information word.
Claim 10
Independent Claim
40 words
A method as claimed in any one of the preceding Claims, characterized in that the control signal is derived from an analogue tracking signal and assumes either of two binary values depending on the polarity of said analogue tracking signal.
Claim 11
Dependent Claim
61 words
An apparatus for carrying out the method as claimed in Claim 1, characterized in that the apparatus comprises an encoding device comprising a first register with the first channel word and a second register with the second channel words, and a selection circuit for selecting a channel word depending on an applied information word and the value of the control signal.
Claim 12
Dependent Claim
54 words
A record carrier obtained by means of one of the methods as claimed in Claims 1 to 9, characterized in that the d.c. content of the recorded digital signal at least substantially varies in the same way as a carrier wave whose frequency is low relative to the bit frequency of the digital signal.
Claim 13
Dependent Claim
58 words
An apparatus for reading a record carrier as claimed in Claim 11, characterized in that the apparatus comprises a detection circuit for extracting the variable d.c. content from the signal read and deriving from said variable d.c. content an error signal which represents the positional error of the read element relative to the information track to be read.
References Cited (Backward Citations)
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