Patent EP0549153A2 successfully refreshed from Google Patents.
EP0549153A2
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Sector mark detection for optical data disks
Assignee: Advanced Micro Devices Inc
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Filing: 1992-12-01
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Granted: —
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Expires: 2012-12-01
Abstract
Abstract The sector mark SM within a long burn data pattern recorded in each sector of an optical disk is detected asynchronously using a robust pattern detection algorithm. The terminal portion of the data pattern at the VFO field of the ANSI X3B11/ISO CCS Standard is ignored. The corner bits at the ends of the remaining pattern and between strings of one and zero bits are ignored, and the pattern that remains is stored in a register. A decoder compares adjacent strings of one and zero bits stored in the register to corresponding predetermined data. Voting circuitry uses a threshold value programmed by the user to determine the presence of a sector mark in the data pattern.
Inventors
- 👤 Shakeel Masood
- 👤 George Li
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 15:20
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/12; G11B20/1217; G11B20/1252; G11B7/00; G11B7/004; G11B7/005; G11B27/00; G11B27/10; G11B27/19; G11B27/28; G11B27/30; G11B27/3027; G11B7/007; G11B2220/00; G11B2220/20
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
115 words
A method of asynchronously detecting a sector mark within a track of an optical disk, wherein said sector mark is characterized by a predefined pattern of alternating strings of one bits and zero bits, comprising the steps of: detecting transitions between said strings of one bits and zero bits forming said pattern; ignoring the corner bits of the pattern at each transition detected in the preceding step; pairing adjacent strings of one bits and zero bits; comparing each pair of adjacent strings of one bits and zero bits with a corresponding predetermined pattern of bits to establish a vote; and evaluating the number of votes obtained in the preceding step to detect a sector mark.
Claim 2
Independent Claim
115 words
A method of asynchronously detecting a sector mark within a track of an optical disk, wherein said sector mark is characterized by a predefined pattern of alternating strings of one bits and zero bits, comprising the steps of: detecting transitions between said strings of one bits and zero bits forming said pattern; ignoring the corner bits of the pattern at each transition detected in the preceding step; pairing adjacent strings of one bits and zero bits; comparing each pair of adjacent strings of one bits and zero bits with a corresponding predetermined pattern of bits to establish a vote; and evaluating the number of votes obtained in the preceding step to detect a sector mark.
Claim 3
Dependent Claim
18 words
The method of claim 1, wherein the number of votes required for detecting a sector mark is pre-selectable.
Claim 4
Dependent Claim
18 words
The method of claim 1, including the step of ignoring bits from a terminal portion of said pattern.
Claim 5
Dependent Claim
19 words
The method of claim 1, including the step of further ignoring the first and last bits of said pattern.
Claim 6
Dependent Claim
14 words
The method of claim 1, wherein said pattern comprises an eighty-bit sector mark pattern.
Claim 7
Independent Claim
127 words
A method of asynchronously detecting a sector mark within a track of an optical disk, wherein said sector mark is characterized by a predefined pattern of alternating series of strings of one and zero bits, comprising the steps of: preconditioning said pattern of bits by detecting transitions between said strings of one bits and zero bits forming said pattern, and ignoring from said pattern the corner bits at each said transition; storing said pattern of bits, preconditioned in the preceding step, in a register; comparing each pair of adjacent strings of one bits and zero bits stored in said register with a corresponding predetermined pattern of bits to establish a vote; and evaluating the number of votes obtained in the preceding step to detect a sector mark.
Claim 8
Independent Claim
127 words
A method of asynchronously detecting a sector mark within a track of an optical disk, wherein said sector mark is characterized by a predefined pattern of alternating series of strings of one and zero bits, comprising the steps of: preconditioning said pattern of bits by detecting transitions between said strings of one bits and zero bits forming said pattern, and ignoring from said pattern the corner bits at each said transition; storing said pattern of bits, preconditioned in the preceding step, in a register; comparing each pair of adjacent strings of one bits and zero bits stored in said register with a corresponding predetermined pattern of bits to establish a vote; and evaluating the number of votes obtained in the preceding step to detect a sector mark.
Claim 9
Dependent Claim
24 words
The method of claim 6, wherein said step of evaluating includes predefining a threshold number of votes constituting a detection of a sector mark.
Claim 10
Dependent Claim
111 words
Apparatus for asynchronously detecting a sector mark having a predefined pattern of bits from among bits read from a track of an optical disk, comprising: a shift register; means for receiving said bits read from said optical disk track, ignoring corner bits at transitions between adjacent series of one bits and zero bits and storing remaining bits in said shift register; comparator means for comparing adjacent strings of one bits and zero bits stored in said shift register with corresponding bit patterns, and, in response, providing particular output signals; and voting logic circuitry for supplying a sector mark found signal in accordance with said output signals obtained from said comparator means.
Claim 11
Dependent Claim
111 words
Apparatus for asynchronously detecting a sector mark having a predefined pattern of bits from among bits read from a track of an optical disk, comprising: a shift register; means for receiving said bits read from said optical disk track, ignoring corner bits at transitions between adjacent series of one bits and zero bits and storing remaining bits in said shift register; comparator means for comparing adjacent strings of one bits and zero bits stored in said shift register with corresponding bit patterns, and, in response, providing particular output signals; and voting logic circuitry for supplying a sector mark found signal in accordance with said output signals obtained from said comparator means.
Claim 12
Dependent Claim
31 words
The apparatus of claim 8, wherein said voting logic circuitry is programmable to supply said sector mark signal in response to a preselected number of matches detected by said comparator means.
Claim 13
Dependent Claim
23 words
The apparatus of claim 8, wherein said first recited means ignores a terminal portion of said pattern read from said optical disk track.
Claim 14
Dependent Claim
23 words
The apparatus of claim 8, wherein said pattern read from said optical disk is an 80-bit pattern, and said register comprises 68 stages.
Claim 15
Dependent Claim
25 words
The apparatus of claim 9, wherein said particular output signals comprise five signals, and said voting logic circuitry is programmable as 3/5 or 4/5 matches.
References Cited (Backward Citations)
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