US3922669A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Television systems
Assignee: Independent Broadcasting Authority
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Filing: 1973-08-22
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Granted: 1975-11-25
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Expires: 1993-08-22
Abstract
Abstract An input signal having a limited set of possible values is compared with a reference signal having a cycle in which values corresponding with the said possible values are repeated in sequence. Output signals are produced when the values of the input signal and the reference signal correspond and their phase relationship with the reference signal represents the values of the input signal. The outputs may be operable to reverse the condition of a binary output so that the timings of the reversals represent magnitudes. Channel economy is obtainable by having more values in the reference signal cycle than the number of possible values in the input signal. It is also obtainable by suppressing the outputs corresponding with pre-determined changes of the input. When applied to digital video recording, the system gives satisfactory results with only a small number of heads, e.g. 4 heads in use at any instant for a 625-line video signal with 2 inch recording tape at 15 inches per second.
Inventors
- 👤 John Lewis Edwin Baldwin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:40
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; H; H04; H04N; H04N9/00; H04N9/79; H04N9/80; H04N9/808; Y; Y10; Y10S; Y10S128/00; Y10S128/03
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
103 words
Apparatus for converting an original input signal of the kind which has a limited set of possible discrete values which comprises an input for said signal, apparatus for generating a cyclic reference signal providing in each cycle a set of values corresponding with the possible values of the input signal and at least one additional value, and a comparator responsive to produce a comparator output when the value of the reference signal corresponds with the value of the input signal, so that comparator outputs are obtained whose relationship to the phase of the reference signal represents the value of the original input signal.
Claim 2
Dependent Claim
103 words
Apparatus for converting an original input signal of the kind which has a limited set of possible discrete values which comprises an input for said signal, apparatus for generating a cyclic reference signal providing in each cycle a set of values corresponding with the possible values of the input signal and at least one additional value, and a comparator responsive to produce a comparator output when the value of the reference signal corresponds with the value of the input signal, so that comparator outputs are obtained whose relationship to the phase of the reference signal represents the value of the original input signal.
Claim 3
Dependent Claim
26 words
Apparatus according to claim 1 for use with binary digital input signals, said apparatus having means for generating a reference signal whose cycle comprises three values.
Claim 4
Dependent Claim
21 words
Apparatus according to claim 1 having means for omitting outputs corresponding with pre-determined changes of the value of the input signal.
Claim 5
Dependent Claim
169 words
Apparatus for converting an original input signal of the kind which has a limited set of possible discrete values which comprises an input for said signal, apparatus for generating a cyclic reference signal providing in each cycle a set of values corresponding with the possible values of the input signal and at least one additional value, a comparator responsive to produce a comparator output when the value of the reference signal corresponds with the value of the input signal, so that comparator outputs are obtained whose relationShip to the phase of the reference signal represents the value of the original input signal, and a binary output circuit giving two output levels and being reversible, on receipt of a comparator output, to change from giving one of said two output levels to give the other of said two output levels so that the timing of a change from one of said two output levels to the other of said two output levels represents the value of the original input signal.
Claim 6
Dependent Claim
169 words
Apparatus for converting an original input signal of the kind which has a limited set of possible discrete values which comprises an input for said signal, apparatus for generating a cyclic reference signal providing in each cycle a set of values corresponding with the possible values of the input signal and at least one additional value, a comparator responsive to produce a comparator output when the value of the reference signal corresponds with the value of the input signal, so that comparator outputs are obtained whose relationShip to the phase of the reference signal represents the value of the original input signal, and a binary output circuit giving two output levels and being reversible, on receipt of a comparator output, to change from giving one of said two output levels to give the other of said two output levels so that the timing of a change from one of said two output levels to the other of said two output levels represents the value of the original input signal.
Claim 7
Dependent Claim
139 words
Apparatus for the recovery of original input signals having a limited number of possible discrete values from received signals derived by comparing said original input signals with a cyclic reference signal providing in each cycle a set of values corresponding with the possible values of the original input signals and at least one additional value so that outputs are obtained whose relationship to the phase of the reference signal represents the value of the original input signal but omitting outputs corresponding with predetermined changes of the value of the original input signal, said apparatus having means for inserting signals corresponding with said predetermined changes in the absence of other signals, means adapted to regenerate the cyclic reference signal and a regenerating device operable to sample the values of the regenerated reference signal at times governed by the received signals.
Claim 8
Dependent Claim
139 words
Apparatus for the recovery of original input signals having a limited number of possible discrete values from received signals derived by comparing said original input signals with a cyclic reference signal providing in each cycle a set of values corresponding with the possible values of the original input signals and at least one additional value so that outputs are obtained whose relationship to the phase of the reference signal represents the value of the original input signal but omitting outputs corresponding with predetermined changes of the value of the original input signal, said apparatus having means for inserting signals corresponding with said predetermined changes in the absence of other signals, means adapted to regenerate the cyclic reference signal and a regenerating device operable to sample the values of the regenerated reference signal at times governed by the received signals.
Claim 9
Dependent Claim
97 words
Apparatus for recovering an original input signal having a limited set of possible discrete values from received signals of the kind represented by comparator outputs whose relationships to the phase of a cyclic reference signal, providing in each cycle a set of values corresponding with the possible values of the input signal and at least one additional value, represent the values of the original input signal, which apparatus comprises means adapted to regenerate the cyclic reference signal, and a regenerating device operable to sample the values of the reference signal at times governed by the received signals.
Claim 10
Dependent Claim
97 words
Apparatus for recovering an original input signal having a limited set of possible discrete values from received signals of the kind represented by comparator outputs whose relationships to the phase of a cyclic reference signal, providing in each cycle a set of values corresponding with the possible values of the input signal and at least one additional value, represent the values of the original input signal, which apparatus comprises means adapted to regenerate the cyclic reference signal, and a regenerating device operable to sample the values of the reference signal at times governed by the received signals.
Claim 11
Dependent Claim
24 words
Apparatus according to claim 6 in which the means adapated to regenerate the cyclic reference signal is responsive for synchronization to the received signals.
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) | 1978-11-24 | 1979-05-26 | 1979-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-24 | 1983-05-26 | 1983-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-24 | 1987-05-26 | 1987-11-25 | $7700.00 | Window Closed / Lapsed |