US4707681A
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Method and apparatus for implementing optimum PRML codes
Assignee: International Business Machines Corp
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Filing: 1986-04-24
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Granted: 1987-11-17
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Expires: 2006-04-24
Abstract
Abstract Rate 8/9, constrained codes having run length limitation parameters (0, 4/4) and (0, 3/6) are provided for any partial response (PR) signalling system employing maximum likelihood (ML) detection.
Inventors
- 👤 John S. Eggenberger
- 👤 Arvind M. Patel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 08:50
CPC Classifications
H; H03; H03M; H03M5/00; H03M5/02; H03M5/04; H03M5/14; H03M5/145
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
95 words
Apparatus for encoding a preselectable number of bits of binary data into codewords having a preselectable number of bits, said apparatus comprising: receiver means for receiving the binary data; and encoder means, coupled to the receiver means, for producing sequences of fixed length codewords; said sequences having no more than a first preselected number of consecutive zeroes therein; and said sequences comprising two subsequences, one consisting only of odd bit positions and another consisting only of even bit positions, each of said subsequences having no more than a second preselected number of consecutive zeroes therein.
Claim 2
Dependent Claim
95 words
Apparatus for encoding a preselectable number of bits of binary data into codewords having a preselectable number of bits, said apparatus comprising: receiver means for receiving the binary data; and encoder means, coupled to the receiver means, for producing sequences of fixed length codewords; said sequences having no more than a first preselected number of consecutive zeroes therein; and said sequences comprising two subsequences, one consisting only of odd bit positions and another consisting only of even bit positions, each of said subsequences having no more than a second preselected number of consecutive zeroes therein.
Claim 3
Dependent Claim
17 words
Apparatus as in claim 1 wherein the first and second preselected number of consecutive zeroes are equal.
Claim 4
Dependent Claim
17 words
Apparatus as in claim 2 wherein the first and second preselected number of consecutive zeroes are 4.
Claim 5
Dependent Claim
17 words
Apparatus as in claim 1 wherein the first and second preselected number of consecutive zeroes are unequal.
Claim 6
Dependent Claim
25 words
Apparatus as in claim 4 wherein the first preselected number of consecutive zeroes is three and the second preselected number of consecutive zeroes is six.
Claim 7
Dependent Claim
28 words
Apparatus as in claim 1 wherein the ratio of the number of bits in the encoded binary data to the number of bits in the codewords is 8/9.
Claim 8
Dependent Claim
44 words
Apparatus as in claim 1 wherein: the codewords comprise a plurality of partitions; and the encoder means includes a plurality of gating means for producing the partitions of codewords and output gating means for combining the partitions of codewords into the sequence of codewords.
Claim 9
Dependent Claim
54 words
Apparatus as in claim 1 further including decoding means for decoding a preselectable number of codewords into a preselectable number of bits of binary data, said decoding means comprising: receiver means for receiving the codewords; and sequential means, coupled to the receiver means, for producing sequences of binary data in response to said codewords.
Claim 10
Dependent Claim
39 words
Apparatus as in claim 8 wherein the sequential means includes a plurality of gating means for producing the partitions of binary data and output gating means for combining the partitions of binary data into the sequences of binary data.
Claim 11
Independent Claim
88 words
A method for encoding a preselectable number of bits of binary data into codewords having a preselectable number of bits, said method comprising the steps of: receiving the binary data; and producing sequences of fixed length codewords; said sequences having no more than a first preselected number of consecutive zeroes therein; and said sequences comprising two subsequences, one consisting only of odd bit positions and another consisting only of even bit positions, each of said subsequences having no more than a second preselected number of consecutive zeroes therein.
Claim 12
Independent Claim
88 words
A method for encoding a preselectable number of bits of binary data into codewords having a preselectable number of bits, said method comprising the steps of: receiving the binary data; and producing sequences of fixed length codewords; said sequences having no more than a first preselected number of consecutive zeroes therein; and said sequences comprising two subsequences, one consisting only of odd bit positions and another consisting only of even bit positions, each of said subsequences having no more than a second preselected number of consecutive zeroes therein.
Claim 13
Dependent Claim
18 words
The method as in claim 10 wherein the first and second preselected number of consecutive zeroes are equal.
Claim 14
Dependent Claim
18 words
The method as in claim 11 wherein the first and second preselected number of consecutive zeroes are 4.
Claim 15
Dependent Claim
18 words
The method as in claim 10 wherein the first and second preselected number of consecutive zeroes are unequal.
Claim 16
Dependent Claim
26 words
The method as in claim 13 wherein the first preselected number of consecutive zeroes is three and the second preselected number of consecutive zeroes is six.
Claim 17
Dependent Claim
29 words
The method as in claim 10 wherein the ratio of the number of bits in the encoded binary data to the number of bits in the codewords is 8/9.
Claim 18
Dependent Claim
39 words
The method as in claim 10 for decoding a preselectable number of codewords into a preselectable number of bits of binary data further comprising the steps of: receiving the codewords; and producing sequences of binary data from said codewords.
Claim 19
Dependent Claim
30 words
Apparatus as in claim 1 wherein the first or second preselected number of consecutive zeroes cannot be decreased without increasing the second or first, respectively, preselected number of consecutive zeroes.
Claim 20
Dependent Claim
22 words
Apparatus as in claim 6 wherein the first or second preselected number of consecutive zeroes cannot be decreased with decreasing said ratio.
References Cited (Backward Citations)
US4567464A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-11-16 | 1991-05-18 | 1991-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-16 | 1995-05-18 | 1995-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-16 | 1999-05-18 | 1999-11-17 | $7700.00 | Window Closed / Lapsed |