# US 2002/0163453 A1 · Information carrier, device for encoding, method for encoding, device for decoding and method for decoding > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2002/0163453 A1 - Document ID: US20020163453A1 - Status: Published application - Kind: A1 - Application number: 10/175,410 - Filed: 2002-06-19 - Published: 2002-11-07 - Earliest claimed: 1999-03-23 - Assignees: Koninklijke Philips Electronics N.V. - Inventors: Marten E. Van Dijk; Willem M. J. M. Coene; Constant P. M. J. Baggen - Web page: https://patentgrep.com/patent/US20020163453A1 ## CPC - G11B 20/10203: {baseline correction (DC correction by choosing codewords of the modulation code G11B20/1426)} - G11B 20/00586: {said format change concerning the physical format of the recording medium} - G11B 20/00884: {involving a watermark, i.e. a barely perceptible transformation of the original data which can nevertheless be recognised by an algorithm} - G11B 20/1426: {conversion to or from block codes or representations thereof} - G11B 20/1809: {by interleaving} - H03M 13/31: combining coding for error detection or correction and efficient use of the spectrum (without error detection or correction H03M5/14 {, H03M5/145}) - G11B 20/00086: {Circuits for prevention of unauthorised reproduction or copying, e.g. piracy (indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00)} - G11B 20/1496: {characterised by the use of more than three levels} - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) - H03M: CODING; DECODING; CODE CONVERSION IN GENERAL (using fluidic means F15C4/00; optical analogue/digital converters G02F7/00; coding, decoding or code conversion, specially adapted for particular applications, see the relevant subclasses, e.g. G01D, G01R, G06F, G06T, G09G, G10L, G11B, G11C, H04B, H04L, H04M, H04N; ciphering or deciphering for cryptography or other purposes involving the need for secrecy G09C) ## Abstract The invention relates to an information carrier comprising runlength limited marks in a track. The runlengths of the marks represent main channel bits and variations of a further parameter of the marks representing secondary channel bits. Not all marks have said variations, only marks of at least a predetermined runlength have said variations. The invention further relates to a device for encoding, a method for encoding, a device for encoding and a method for decoding. ## Claims ### Claim 1 An information carrier comprising runlength limited marks in a track, the runlengths of the marks representing main channel bits and variations of a further parameter of the marks representing secondary channel bits, characterized in that only marks of at least a predetermined runlength have said variations. ### Claim 2 (depends on 1) An information carrier as claimed in claim 1, characterized in that the parameter is the width of the mark or space. ### Claim 3 (depends on 1, 2) An information carrier as claimed in claim 1 or 2, characterized in that the runlength limited data obeys constraints d=2, k=10, and in that the predetermined minimum runlength is 6. ### Claim 4 (depends on 1) An information carrier as claimed in claim 1, characterized in that the secondary channel of data also comprises error-correction data. ### Claim 5 (depends on 1) An information carrier as claimed in claim 1, characterized in that the marks are pits and lands, the pits having a reduced depth, the lands having a pit of small depth. ### Claim 6 A device for encoding comprising converting means for converting a binary source signal into a channel signal, the channel signal comprising a main channel signal representing main channel bits and a secondary channel signal representing secondary channel bits, the converting means being further arranged for detecting the runlengths of the main channel bits and the converting means further comprising inserting means for generating the secondary channel signal only upon detecting a runlength of a predetermined minimum runlength. ### Claim 7 (depends on 6) A device as claimed in claim 6, wherein the device further comprises writing means for writing the channel signal on a record carrier. ### Claim 8 A method for encoding comprising the step of converting a binary source signal into a channel signal, the channel signal comprising a main channel signal representing main channel bits and a secondary channel signal representing secondary channel bits, the method further comprising the step of detecting the runlengths of the main channel bits and the method further comprising the step of generating the secondary channel signal only upon detecting a runlength of a predetermined minimum runlength. ### Claim 9 (depends on 8) A method as claimed in claim 8, wherein the method further comprises the step of writing the channel signal on a record carrier. ### Claim 10 A device for decoding comprising decoding means for decoding a channel signal into a binary source signal, the channel signal comprising a main channel signal comprising main channel bits and a secondary channel signal comprising secondary channel bits, the device further comprising detecting means for detecting the runlengths of the main channel bits, the decoding means being further arranged for detecting the secondary channel only upon detecting a runlength of a predetermined minimum runlength. ### Claim 11 (depends on 10) A device as claimed in claim 10, wherein the device further comprises reading means for reading out the channel signal from a record carrier. ### Claim 12 A method for decoding comprising the step of decoding a channel signal into a binary source signal, the channel signal comprising a main channel signal comprising main channel bits and a secondary channel signal comprising secondary channel bits, the method further comprising the step of detecting the runlengths of the main channel bits and the method further comprising the step of detecting the secondary channel only upon detecting a runlength of a predetermined minimum runlength. ### Claim 13 (depends on 12) A method as claimed in claim 12, wherein the method further comprises the step of reading the channel signal from a record carrier.