Patent US3715489A successfully refreshed from Google Patents.
US3715489A
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US
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Apparatus for preventing buffer overflow in video encoding systems by increasing the scanning rate of a camera during the time interval of the encoding of digital words of extra length
Assignee: AT&T Inc
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Filing: 1971-02-23
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Granted: 1973-02-06
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Expires: 1991-02-23
Abstract
Abstract To prevent buffer overflow from line-to-line accumulation of information in video encoding systems, a detector circuit notes the occurrence of extra words or extra digits produced by a variable word length encoder. In response to this detection, a voltage adding means incrementally alters the slope of the horizontal sweep sawtooth which, in turn, results in a temporary increase in camera scanning speed. Logic means insures that the time obtained from the active scanning region by increasing scanning speed is allocated to the blanking interval.
Inventors
- 👤 E Brown
- 👤 W Kaminski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:10
CPC Classifications
H; H04; H04N; H04N21/00; H04N21/40; H04N21/43; H04N21/434; H04N19/00; H04N21/20; H04N21/23; H04N21/236; H04N3/00; H04N3/10; H04N3/30; H04N3/32
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
147 words
In a video system for transmitting information encoded in frame intervals which are subdivided into lines, each line comprising an active interval and a blanking interval, encoding apparatus comprising: means for generating a video signal by scanning a video image, a line at a time, initiation of scanning a new line occurring at fixed intervals; means for sampling the video signal; means for digitally encoding the video samples; buffer means for storing the encoding samples prior to transmission; means for detecting a condition of impending buffer overflow; and means for controlling the rate of scanning in said means for generating a video signal in response to said detecting means, whereby the amount of information produced per line is kept relatively constant, the active interval of a line is shortened and the blanking interval of the line is lengthened in response to a condition of impending buffer overflow.
Claim 2
Dependent Claim
147 words
In a video system for transmitting information encoded in frame intervals which are subdivided into lines, each line comprising an active interval and a blanking interval, encoding apparatus comprising: means for generating a video signal by scanning a video image, a line at a time, initiation of scanning a new line occurring at fixed intervals; means for sampling the video signal; means for digitally encoding the video samples; buffer means for storing the encoding samples prior to transmission; means for detecting a condition of impending buffer overflow; and means for controlling the rate of scanning in said means for generating a video signal in response to said detecting means, whereby the amount of information produced per line is kept relatively constant, the active interval of a line is shortened and the blanking interval of the line is lengthened in response to a condition of impending buffer overflow.
Claim 3
Dependent Claim
147 words
In a video system for transmitting information encoded in frame intervals which are subdivided into lines, each line comprising an active interval and a blanking interval, encoding apparatus comprising: means for generating a video signal by scanning a video image, a line at a time, initiation of scanning a new line occurring at fixed intervals; means for sampling the video signal; means for digitally encoding the video samples; buffer means for storing the encoding samples prior to transmission; means for detecting a condition of impending buffer overflow; and means for controlling the rate of scanning in said means for generating a video signal in response to said detecting means, whereby the amount of information produced per line is kept relatively constant, the active interval of a line is shortened and the blanking interval of the line is lengthened in response to a condition of impending buffer overflow.
Claim 4
Dependent Claim
147 words
In a video system for transmitting information encoded in frame intervals which are subdivided into lines, each line comprising an active interval and a blanking interval, encoding apparatus comprising: means for generating a video signal by scanning a video image, a line at a time, initiation of scanning a new line occurring at fixed intervals; means for sampling the video signal; means for digitally encoding the video samples; buffer means for storing the encoding samples prior to transmission; means for detecting a condition of impending buffer overflow; and means for controlling the rate of scanning in said means for generating a video signal in response to said detecting means, whereby the amount of information produced per line is kept relatively constant, the active interval of a line is shortened and the blanking interval of the line is lengthened in response to a condition of impending buffer overflow.
Claim 5
Dependent Claim
56 words
Encoding apparatus as described in claim 1 wherein said means for controlling the rate of scanning comprises: means for generating sweep signals; means responsive to said detecting means for incrementally varying the instantaneous rate of amplitude change of signals from said sweep generating means; and means responsive to said detecting means for commencing the blanking interval.
Claim 6
Dependent Claim
53 words
Encoding apparatus as described in claim 2 wherein said means for incrementally varying the instantaneous rate comprises: means responsive to said detecting means for producing a pulse each time said detecting means indicates a condition of impending buffer overflow, and means for combining said pulse with the signals from said sweep generating means.
Claim 7
Dependent Claim
76 words
Encoding apparatus as described in claim 2 wherein said means for commencing the blanking interval comprises: bistable means for commencing the blanking interval upon the occurrence of a first signal pulse and for terminating the blanking interval upon receiving a second signal pulse; counting means responsive to said detecting means for producing said first signal pulse upon reaching a predetermined count; and means cooperative with said sweep generating means for periodically producing said second signal pulse.
Claim 8
Dependent Claim
36 words
Encoding apparatus as described in claim 1 wherein said encoding means comprises means for digitally encoding the video samples in a first or a second encoding mode, depending upon the amplitude of signals to be encoded.
Claim 9
Dependent Claim
40 words
Encoding apparatus as described in claim 5 wherein said means for detecting a condition of impending buffer overflow comprises: means responsive to said encoding means for producing signals upon the operation of said encoding means in said second encoding mode.
Claim 10
Dependent Claim
108 words
Encoding apparatus as described in claim 1 wherein said means for detecting a condition of impending buffer overflow includes means for detecting a situation in which the number of digits per line being produced by said means for digitally encoding is in excess of the number of digits which can be transmitted from said buffer means in an equivalent time, and said means for controlling includes means for changing the rate of scanning of said means for generating a video signal for a time duration proportional to the number of digits being produced per line in excess of the number which can be transmitted from said buffer means.
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) | 1976-02-06 | 1976-08-07 | 1977-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-06 | 1980-08-07 | 1981-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-06 | 1984-08-07 | 1985-02-06 | $7700.00 | Window Closed / Lapsed |