Patent US4377911A successfully refreshed from Google Patents.
Patent US3950616A successfully refreshed from Google Patents.
US3950616A
Expired / Lapsed
US
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Alignment of bytes in a digital data bit stream
Assignee: AT&T Inc
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Filing: 1975-04-08
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Granted: 1976-04-13
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Expires: 1995-04-08
Abstract
Abstract A sequence of data bytes, which includes a low signaling rate control signal inserted in the framing bit position of each byte, is prepared for transmission by scrambling the information bits while maintaining the framing bit position unscrambled. Pairs of bits occupying a corresponding bit position in different bytes are compared at the receiver and comparison mismatches are counted. The framing bit position is identified by bits having a rate of change in their binary condition which does not exceed a predetermined count rate which is in excess of the low signaling rate of the control signal and is less than the anticipated rate of change of the scrambled information bits. The receiver, when aligned with the framing bit position, is enabled to recover the control signal and unscramble the information bits.
Inventors
- 👤 Tarmo Tammaru
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 18:26
CPC Classifications
H; H04; H04L; H04L7/00; H04L7/04; H04L7/08; H04L25/00; H04L25/02; H04L25/03; H04L25/03828; H04L25/03866
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
134 words
In a data transmission system including means at a transmitting station for transmitting binary data bits arranged in groups having control bits in a corresponding bit position in each group, control bits in different groups conveying information at a low speed signaling rate and means at a receiving station for identifying the bit position of the control bits, characterized in that the transmitting means includes means for scrambling the data bits while maintaining the bits in the corresponding bit position unscrambled, and the identifying means includes means for detecting rates of change of the binary condition of the bits occupying a corresponding bit position in different groups not exceeding a predetermined rate which is in excess of the low speed signaling rate and less than the anticipated rate of change of the scrambled bits.
Claim 2
Dependent Claim
134 words
In a data transmission system including means at a transmitting station for transmitting binary data bits arranged in groups having control bits in a corresponding bit position in each group, control bits in different groups conveying information at a low speed signaling rate and means at a receiving station for identifying the bit position of the control bits, characterized in that the transmitting means includes means for scrambling the data bits while maintaining the bits in the corresponding bit position unscrambled, and the identifying means includes means for detecting rates of change of the binary condition of the bits occupying a corresponding bit position in different groups not exceeding a predetermined rate which is in excess of the low speed signaling rate and less than the anticipated rate of change of the scrambled bits.
Claim 3
Dependent Claim
50 words
In a data transmission system, in accordance with claim 1, wherein the identifying means includes means for comparing pairs of bits individually occupying a corresponding one of the bit positions in different groups and means responsive to a ratio of comparison mismatches to pair comparisons for designating the predetermined rate.
Claim 4
Dependent Claim
41 words
In a data transmission system, in accordance with claim 2, wherein the identifying means further includes means responsive to the designating means for shifting the comparing means to compare pairs of bits occupying a different corresponding one of the bit positions.
Claim 5
Dependent Claim
59 words
In a data transmission system, in accordance with claim 3, wherein the identifying means further includes means for generating a pulse during a corresponding one of the bit positions of each of the groups and means responsive to the comparing means for aligning the generating means with the corresponding one of the bit positions occupied by the compared bits.
Claim 6
Dependent Claim
63 words
In a data transmission system, in accordance with claim 4, wherein the designating means includes means for counting pair comparisons, means for counting comparison mismatches and means for defining an out-of-frame condition in response to an advance of the comparison mismatch counting means to a selected mismatch count before an advance of the pair comparison counting means to a selected pair comparison count.
Claim 7
Dependent Claim
52 words
In a data transmission system, in accordance with claim 5, wherein the defining means includes means for defining an in-frame condition in response to the advance of the pair comparison counting means to the selected pair comparison count before the advance of the comparison mismatch counting means to the selected mismatch count.
Claim 8
Dependent Claim
24 words
In a data transmission system, in accordance with claim 6, wherein the aligning means is enabled by the defining means defining the in-frame condition.
Claim 9
Dependent Claim
24 words
In a data transmission system, in accordance with claim 6, wherein the shifting means is enabled by the defining means defining the out-of-frame condition.
Claim 10
Dependent Claim
27 words
In a data transmission system, in accordance with claim 4, wherein means at the receiving station repsonsive to the pulse generating means recovers the unscrambled control bits.
Claim 11
Dependent Claim
27 words
In a data transmission system, in accordance with claim 4, wherein means at the receiving station responsive to the pulse generating means unscrambles the scrambled data bits.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-04-13 | 1979-10-13 | 1980-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-13 | 1983-10-13 | 1984-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-13 | 1987-10-13 | 1988-04-13 | $7700.00 | Window Closed / Lapsed |