US3859513A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Switching and digital system
Assignee: University of Washington
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Filing: 1973-02-28
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Granted: 1975-01-07
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Expires: 1993-02-28
Abstract
Abstract An increased reliability switching or digital system comprising at least two identical logic networks and restorer means. Each of the logic networks has an output providing three distinctly different types of output signals, viz., correct, safe and incorrect so that there are two possible levels of failure, one being a safe level and the other being an incorrect level. The restorer means has inputs connected to the logic network outputs and has a single output providing three distinctly different types of output signals, the first of which is correct, the second of which is safe, and the third being incorrect. The restorer means provides a correct output signal for so long as more of the logic networks have correct output signals than have incorrect output signals no matter how many networks might have a safe output signal. Further, the restorer means provides a safe output signal if as many logic networks have a correct output signal as have an incorrect output signal. Additionally disclosed is apparatus for interfacing double-rail and single-rail logic components.
Inventors
- 👤 Henry Ying Huang Chuang
- 👤 Santanu Das
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:20
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/16; G06F11/18; G06F11/181; G06F11/187; G06F11/20; G06F11/183
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
183 words
An increased reliability switching or digital system comprising at least two identical logic networks each of which has an output providing three distinctly different types of output signals, said types of output signals being correct, safe and incorrect, whereby there are two possible levels of failure one being a safe level and the other being an incorrect level; and restorer means having inputs connected to the logic network outputs and having a single output providing three distinctly different types of output signals, the first of which is correct, the second of which is safe, and the third being incorrect, said restorer means providing a correct output signal for so long as more of the logic networks have correct output signals than have incorrect output signals no matter how many networks might have a safe output signal, said restorer means further providing a safe output signal if as many logic networks have a correct output signal as have an incorrect output signal, said restorer means providing an incorrect output signal only if more logic networks have incorrect output signals than have correct output signals.
Claim 2
Dependent Claim
183 words
An increased reliability switching or digital system comprising at least two identical logic networks each of which has an output providing three distinctly different types of output signals, said types of output signals being correct, safe and incorrect, whereby there are two possible levels of failure one being a safe level and the other being an incorrect level; and restorer means having inputs connected to the logic network outputs and having a single output providing three distinctly different types of output signals, the first of which is correct, the second of which is safe, and the third being incorrect, said restorer means providing a correct output signal for so long as more of the logic networks have correct output signals than have incorrect output signals no matter how many networks might have a safe output signal, said restorer means further providing a safe output signal if as many logic networks have a correct output signal as have an incorrect output signal, said restorer means providing an incorrect output signal only if more logic networks have incorrect output signals than have correct output signals.
Claim 3
Dependent Claim
19 words
A system as set forth in claim 1 in which said logic networks and said restorer means are N-fail-safe.
Claim 4
Dependent Claim
21 words
A system as set forth in claim 1 in which said logic networks and said restorer means have two rail outputs.
Claim 5
Dependent Claim
27 words
A system as set forth in claim 1 which further includes means interconnected with the inputs of each logic network for converting single-rail signals to two-rails signals.
Claim 6
Dependent Claim
25 words
A system as set forth in claim 3 which further includes means for converting two-rail output signals of said restorer means to single-rail output signals.
Claim 7
Dependent Claim
23 words
A system as set forth in claim 3 in which said logic networks and restorer means are fabricated in accordance with MOS/MSI techniques.
Claim 8
Dependent Claim
23 words
A system as set forth in claim 2 in which said logic networks and restorer means include components which have asymmetrical failure characteristics.
Claim 9
Dependent Claim
81 words
A system as set forth in claim 1 which includes additional restorer means interconnected with the outputs of said logic networks, the outputs of both the first said and additional restorer means being connected to the inputs of respective additional logic networks, and further restorer means having the inputs thereof responsive to the outputs of said additional logic networks, said further restorer means having higher reliability than the first said restorer means whereby the reliability of the system is further improved.
Claim 10
Dependent Claim
21 words
A system as set forth in claim 1 wherein said logic networks include means for detecting a safe output signal therefrom.
Claim 11
Dependent Claim
21 words
A system as set forth in claim 1 further including means for detecting a safe output signal from the restorer means.
Claim 12
Dependent Claim
24 words
A system as set forth in claim 1 further including means for detecting a safe output signal from both logic networks and restorer means.
Claim 13
Dependent Claim
39 words
A system as set forth in claim 11 which further includes means responsive to safe output signals both from the logic networks and the restorer means for restoring the system under concurrent failures in more than one logic network.
Claim 14
Dependent Claim
32 words
A system as set forth in claim 9 further including means responsive to a safe output signal from any logic network for permanently forcing the output thereof to a safe output signal.
Claim 15
Dependent Claim
45 words
A system as set forth in claim 9 which further includes at least one spare logic network and means responsive to a safe output signal from a logic network for deactivating the last said logic network and activating in its stead a spare logic network.
Claim 16
Dependent Claim
119 words
Apparatus for converting a double-rail signal to a single-rail signal comprising a high-frequency generator, a radiation source responsive to one element of said double-rail signal thereby to be energized by said high-frequency signal, means responsive to the other element of said double-rail signal and radiation proDuced by said source for generating an a.c. signal, and means for rectifying said a.c. signal to provide a single-rail signal which corresponds to one of the double-rail signals, said generator having an operating frequency substantially higher than that of said double-rail signal, said radiationresponsive means being nonconductively coupled to said radiation source thereby to provide electrical isolation between said one element and said radiation-responsive means and to effect fail-safe operation of said apparatus.
Claim 17
Dependent Claim
119 words
Apparatus for converting a double-rail signal to a single-rail signal comprising a high-frequency generator, a radiation source responsive to one element of said double-rail signal thereby to be energized by said high-frequency signal, means responsive to the other element of said double-rail signal and radiation proDuced by said source for generating an a.c. signal, and means for rectifying said a.c. signal to provide a single-rail signal which corresponds to one of the double-rail signals, said generator having an operating frequency substantially higher than that of said double-rail signal, said radiationresponsive means being nonconductively coupled to said radiation source thereby to provide electrical isolation between said one element and said radiation-responsive means and to effect fail-safe operation of said apparatus.
Claim 18
Dependent Claim
20 words
Apparatus as set forth in claim 15 which further includes electrical isolation means between said radiation-responsive means and said rectifier.
Claim 19
Dependent Claim
24 words
Apparatus as set forth in claim 16 in which said isolation means includes an amplifier and transformer coupling between said amplifier and said rectifier.
Claim 20
Dependent Claim
34 words
Apparatus as set forth in claim 15 in which said radiation source is a light-emitting diode and said radiation-responsive means is a light-sensitive solid-state switching device, said diode and switching device being optically coupled.
Claim 21
Dependent Claim
15 words
Apparatus as set forth in claim 15 in which the double-rail input signal is N-fail-safe.
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) | 1978-01-06 | 1978-07-08 | 1979-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-06 | 1982-07-08 | 1983-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-06 | 1986-07-08 | 1987-01-07 | $7700.00 | Window Closed / Lapsed |