EP0455267A2
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EP
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Data demodulation system
Assignee: Sharp Corp
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Filing: 1987-01-30
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Granted: —
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Expires: 2007-01-30
Abstract
Abstract Disclosed is a data demodulation system for reproducing data dividedly recorded in a plurality of recording blocks of a recording medium, comprising the steps of adding specified data patterns to the data bits of dividing portions of each recording block and modulating the recording block and specified data patterns, and adding a specified coded pattern to the modulator signal pattern.
Inventors
- 👤 Kentaroh Tsuji
- 👤 Tsuneo Fujiwara.
- 👤 Shigemi Maeda
- 👤 Takeshi Yamaguchi
- 👤 Toshihisa Daiya-Heights Gakuenmae C-722 Deguchi
- 👤 Shozou Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 19:29
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/12; G11B20/14; G11B20/1403; G11B20/1423; G11B20/1426; G11B27/00; G11B27/10; G11B27/19; G11B27/28; G11B27/30; G11B27/3027; H; H03; H03M; H03M5/00; H03M5/02; H03M5/04; H03M5/14; H03M5/145; G11B2220/00; G11B2220/20
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
77 words
A method of forming a pattern for a resynchronisation signal, said pattern being to be recorded in a recording medium in which data are recorded in a plurality of blocks, comprising the steps of: (a) adding one or more specified data bit patterns to the data bits of dividing portions of each block; (b) modulating said specified data bit patterns; and (c) adding one or more specified code bit patterns to said modulated specified data bit patterns.
Claim 2
Independent Claim
102 words
A method for providing a modulated signal and synchronisation pattern from a data signal dividedly recorded in a plurality of recording blocks on a recording medium, comprising the steps of: adding a specified data pattern to a data dividing portion of each recording block; modulating each recording block and its specified data pattern to provide a respective coded signal portion separated from adjacent coded signal portions at coded dividing portions; and adding a specified coded pattern to the coded signal portion at a said coded dividing portion for detection for resynchronisation, the specified code pattern being distinguishable from the coded signal portions.
Claim 3
Dependent Claim
40 words
A method according to claim 2 further comprising the steps of: detecting the specified coded pattern to locate the dividing portions of the recording blocks; demodulating each coded signal portion to return to the recording block and specified data pattern.
Claim 4
Dependent Claim
29 words
A method according to claim 2 or claim 3 wherein the specified data pattern is configured to enable the entire data signal of each recording block to be modulated.
Claim 5
Independent Claim
25 words
A method according to any one of claims 2 to 4 wherein the specified data pattern is added to the end of each recording block.
Claim 6
Independent Claim
26 words
A method according to any one of claims 2 to 5 wherein the specified coded pattern is added to the end of each coded signal portion.
Claim 7
Dependent Claim
48 words
A method according to claim 3 or any claim dependent thereon wherein the step of detecting the specified coded pattern to locate the dividing portions of the recording blocks comprises determining the position of the beginning of a coded signal portion by detection of the specified coded pattern.
Claim 8
Dependent Claim
47 words
A method according to any one of claim 2 to 7 wherein the step of modulating each recording block and its specified data pattern comprises 2-7 modulation and wherein the specified coded pattern satisfies the 2-7 word length requirement but does not satisfy the 2-7 conversion requirement.
Claim 9
Dependent Claim
111 words
Apparatus for modulation/demodulation of a data signal dividedly recorded in a plurality of recording blocks on a recording medium comprising: means for adding a specified data pattern to a data dividing portion of each recording block; means for modulating each recording block and its specified data signal to provide a respective coded signal portion separated from adjacent coded signal portions at coded dividing portions; means for adding a specified coded pattern to the coded signal portion at a said coded dividing portion of each coded signal block, the specified coded signal portion being distinguishable from the coded signal portions; and means responsive to detection of the specified coded pattern for resynchronisation.
Claim 10
Dependent Claim
134 words
A data demodulation system for reproducing the data being divided and recorded in plural blocks in a recording medium, comprising the steps of modulating by adding specified data bit patterns to the data bits of dividing portions of each block, and reproducing the data from the recording medium in which record patterns obtained by adding specified code bit patterns are added after modulation are recorded, wherein bit rows are independently demodulated by demodulation clocks differing mutually in phase, the demodulation bit pattern of the above code bit pattern added at the time of recording and the bit pattern demodulated by the different modulation clock are compared with each other to check if wrong or not, and the correct one of the two sets of demodulated data is selected according to this result and delivered.
Claim 11
Dependent Claim
94 words
A data demodulation system in which a signal which includes coded data signal portions and a signal portion comprising a predetermined signal pattern (Fig. 6a) which on correct demodulation produces a known demodulation pattern (Fig. 6b), is demodulated using a plurality of mutually phase-shifted demodulating clock signals (DMCK1, DMCK2), wherein there is provided means (17) for comparing the demodulated versions of the predetermined signal pattern obtained using the different clock signals with said known demodulation pattern to determine which of the demodulating clock signals will produce correct demodulation of the coded data signal portions.
Claim 12
Dependent Claim
84 words
A data demodulation system according to claim 11 wherein the signal to be demodulated can be divided into signal blocks, each including coded data signal portions and a said predetermined signal pattern (Fig. 6a), and wherein said comparing means is operable for each signal block to compare said demodulated versions of the signal pattern of that block with said known demodulation pattern and to determine which of the demodulating clock signals will produce correct demodulation of the coded data signal portions of that block.
Claim 13
Dependent Claim
83 words
A data demodulation system according to claim 11 or claim 12 wherein there are provided first and second demodulation means (13, 14) for demodulating the signal using first and second said demodulating clock signals respectively, and a signal selection means (18) coupled to receive the demodulated signals from said first and second demodulation means and controlled in accordance with the output of said comparing means (17) to select that one of said demodulated signals which is correctly. demodulated, for output from the system.
Claim 14
Dependent Claim
38 words
A data demodulation system according to any of claims 11 to 13 wherein said predetermined signal pattern (Fig. 6a) is a pattern which cannot be produced by the encoding system used to produce said coded data signal portions.
References Cited (Backward Citations)
No citation records indexed.
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