Patent US5223930A successfully refreshed from Google Patents.
US5223930A
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US
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Data recovery system using dot clock counting
Assignee: LG Electronics Inc
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Filing: 1991-10-18
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Granted: 1993-06-29
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Expires: 2011-10-18
Abstract
Abstract A closed caption system includes digital data on a line in the vertical blanking interval of a television signal. The line is preceded by a run-in signal of the same frequency as the data. A start bit follows the run-in signal. A high frequency dot clock is used to sample the run-in signal, and the number of dot clocks during a period of the run-in signal is used to control subsequent sampling of the data, which is initiated by the start bit.
Inventors
- 👤 Thomas J. Zato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 04:21
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/025; H04N7/035; H04N7/0355
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
72 words
A method of recovering digital data preceded by a run-in signal of the same frequency comprising: sampling one cycle of the run-in signal with a high frequency dot clock to determine, from the number of dot clocks occurring in said sample, the repetition rate of the run-in signal; and sampling the digital data at a repetition rate corresponding to said number of dot clocks occurring in said sample of said run-in signal.
Claim 2
Independent Claim
72 words
A method of recovering digital data preceded by a run-in signal of the same frequency comprising: sampling one cycle of the run-in signal with a high frequency dot clock to determine, from the number of dot clocks occurring in said sample, the repetition rate of the run-in signal; and sampling the digital data at a repetition rate corresponding to said number of dot clocks occurring in said sample of said run-in signal.
Claim 3
Dependent Claim
29 words
The method of claim 1 wherein said run-in signal is followed by a start bit and wherein said sampling of the digital data is initiated by said start bit.
Claim 4
Dependent Claim
46 words
The method of claim 2 wherein said sampling of said run-in signal comprises: counting the number of dot clocks occurring in a period of said run-in signal; and comparing said number of counted dot clocks with a known number for one period of said run-in signal.
Claim 5
Dependent Claim
35 words
The method of claim 3 comprising: counting a pattern of dot clocks for successive periods of said run-in signal; remembering the pattern of said counted dot clocks; and sampling said data using said remembered pattern.
Claim 6
Independent Claim
111 words
A method of recovering digital data preceded by a run-in signal of the same frequency followed by a start bit comprising: sampling the run-in signal with a high frequency dot clock to determine the repetition rate of the run-in signal by counting the number of dot clocks occurring in the first period of said run-in signal and comparing said number of counted dot clocks with a known number for one period of said run-in signal; and sampling the digital data at a repetition rate corresponding to the number of dot clocks counted in said first period of said run-in signal, said sampling of digital data being initiated by said start bit.
Claim 7
Independent Claim
111 words
A method of recovering digital data preceded by a run-in signal of the same frequency followed by a start bit comprising: sampling the run-in signal with a high frequency dot clock to determine the repetition rate of the run-in signal by counting the number of dot clocks occurring in the first period of said run-in signal and comparing said number of counted dot clocks with a known number for one period of said run-in signal; and sampling the digital data at a repetition rate corresponding to the number of dot clocks counted in said first period of said run-in signal, said sampling of digital data being initiated by said start bit.
Claim 8
Dependent Claim
35 words
The method of claim 5 comprising: counting a pattern of dot clocks for successive periods of said run-in signal; remembering the pattern of said counted dot clocks; and sampling said data using said remembered pattern.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-06-28 | 1996-12-28 | 1997-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-28 | 2000-12-28 | 2001-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-28 | 2004-12-28 | 2005-06-29 | $7700.00 | Window Closed / Lapsed |