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US3582546A
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Redundancy reduction system for use with a signal having frame intervals
Assignee: AT&T Inc
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Filing: 1969-06-13
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Granted: 1971-06-01
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Expires: 1989-06-13
Abstract
Abstract A redundancy reduction system is described in which plural amplitude samples of a video signal are taken during each frame interval. The amplitude values for each set of four samples are coupled to the input of a circuit which operates in accordance with a fixed function to produce an indicator word for that set. The indicator words thereby generated for an entire frame interval are stored in a frame memory at positions in the memory corresponding to their respective set positions within the frame interval. In succeeding frames a similarly generated indicator word for a set of samples is compared with its corresponding stored indicator word from the frame memory. Only if a difference exists between the two indicator words is the set of new amplitude samples transmitted to a receiving location.
Inventors
- 👤 Earl F Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:10
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/10; H04N19/134; H04N19/146; H04N19/152; H04N19/50; H04N19/503
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
149 words
Redundancy reduction transmitting apparatus for use with a signal having periodic frame intervals, said apparatus comprising means for generating address words each one of which indicates a time position within said frame interval, means for sampling said signal a plurality of times during each frame interval, means for generating indicator words each one of which has an amplitude which is a function of a set of a predetermined number of signal samples, means for storing the indicator words generated for an entire frame interval, means for comparing a newly generated indicator word with a stored indicator word corresponding to a previous set of samples having the same time position in a frame interval, and means for transmitting an address word and the samples in a set if those samples result in an indicator word having a value which is different from the value of its corresponding stored indicator word.
Claim 2
Dependent Claim
149 words
Redundancy reduction transmitting apparatus for use with a signal having periodic frame intervals, said apparatus comprising means for generating address words each one of which indicates a time position within said frame interval, means for sampling said signal a plurality of times during each frame interval, means for generating indicator words each one of which has an amplitude which is a function of a set of a predetermined number of signal samples, means for storing the indicator words generated for an entire frame interval, means for comparing a newly generated indicator word with a stored indicator word corresponding to a previous set of samples having the same time position in a frame interval, and means for transmitting an address word and the samples in a set if those samples result in an indicator word having a value which is different from the value of its corresponding stored indicator word.
Claim 3
Dependent Claim
48 words
Transmitting apparatus as defined in claim 1 wherein said means for generating an indicator word includes means for successively subtracting the amplitude values of the samples in a set and further includes means for selecting only the least significant bits derived from the result of said successive subtractions.
Claim 4
Dependent Claim
89 words
Transmitting apparatus as defined in claim 2 wherein said means for performing said successive subtractions includes a subtractor circuit having a first and a second input with said first input connected to receive the amplitude value of each sample in the set of samples, a delay circuit means having a delay equal to the interval between adjacent samples with its input connected to the output of said subtractor circuit, and gating means for connecting the output of the delay circuit means to said second input of said subtractor circuit.
Claim 5
Dependent Claim
128 words
Redundancy reduction transmitting apparatus for use with a signal having periodic frame intervals, said apparatus comprising means for generating a plurality of address words during each frame interval, each one of said address words having a value which indicates the time position in said frame interval, means for sampling said signal a plural numbeR of times between address words, the plurality of samples following each address word being called a set of samples, means for comparing the amplitude values of the samples in a set with the amplitude values of a previous set of samples having the same time position in a frame interval, means responsive to an indicated difference in said comparison for coupling said each address word and its corresponding amplitude samples to a transmission channel.
Claim 6
Dependent Claim
128 words
Redundancy reduction transmitting apparatus for use with a signal having periodic frame intervals, said apparatus comprising means for generating a plurality of address words during each frame interval, each one of said address words having a value which indicates the time position in said frame interval, means for sampling said signal a plural numbeR of times between address words, the plurality of samples following each address word being called a set of samples, means for comparing the amplitude values of the samples in a set with the amplitude values of a previous set of samples having the same time position in a frame interval, means responsive to an indicated difference in said comparison for coupling said each address word and its corresponding amplitude samples to a transmission channel.
Claim 7
Dependent Claim
34 words
Transmitting apparatus as defined in claim 4 wherein said means for comparing includes a means for generating an indicator word whose value is dependent on the amplitude values of the samples in a set.
Claim 8
Dependent Claim
100 words
Transmitting apparatus as defined in claim 5 wherein said means for generating an indicator word includes a subtractor circuit having two inputs and an output, means for connecting the amplitude samples to one of said two inputs of said subtractor circuit, means for delaying the output of said subtractor circuit for an interval equal in duration to the time between adjacent samples, and means for gating the delayed output of said subtractor circuit to the second of said two inputs of said subtractor circuit, and means for selecting the least significant digits of said delayed output as an indicator word.
Claim 9
Dependent Claim
60 words
Transmitting apparatus as defined in claim 6 wherein said means for coupling includes an address delay means having a delay time equal to the duration of a set of samples, and an amplitude delay means for delaying said amplitude samples a duration of time greater than that of the address delay means by one-half of the interval between adjacent samples.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-31 | 1974-11-30 | 1975-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-31 | 1978-11-30 | 1979-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-31 | 1982-11-30 | 1983-06-01 | $7700.00 | Window Closed / Lapsed |