US3665108A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multiplexing systems
Assignee: General Dynamics Corp
•
Filing: 1969-10-20
•
Granted: 1972-05-23
•
Expires: 1989-10-20
Abstract
Abstract A multiplexing system having high speed sampling capability, even in cases of high source impedance which would ordinarily cause errors which are a function of the source resistance and capacitance, is described. The system includes a plurality of commutator switches or gates which are connected in series with the sources. An operational amplifier is provided having a feedback path connected between the output and inverting input of the amplifier and including the series connected switches and sources. The direct input of the amplifier is connected to ground or some other voltage which is approximately equal to the return potential of the source. The output of the amplifier therefore is equal to the sampled voltage and the amplifier compensates for the errors in the sampled voltage which would be produced by charging effects in the source impedance when insufficient time is not allotted for settling due, for example, to a high rate of sampling.
Inventors
- 👤 John O Bowers Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:47
CPC Classifications
H; H04; H04J; H04J3/00; H04J3/02; H04J3/04; H04J3/047; G; G08; G08C; G08C15/00; G08C15/06
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
143 words
A multiplexing system for sequentially sampling input signals from a plurality of source, each having a pair of terminals, one of which is at relatively low potential, which system comprises a. a gate circuit for each of said sources, b. a difference amplifier having a pair of inputs, one of which is connected to a point of reference potential, and c. a feedback circuit from the output of said amplifier to an input thereof having a plurality of separate feedback paths each including a different one of said sources and the gate circuit therefor in series therein, each of said paths having a connection between a different one of said sources and the output of said amplifier via said gate circuit therefor, and means for connecting the other of said pair of amplifier inputs to said one terminal of said last named source.
Claim 2
Dependent Claim
143 words
A multiplexing system for sequentially sampling input signals from a plurality of source, each having a pair of terminals, one of which is at relatively low potential, which system comprises a. a gate circuit for each of said sources, b. a difference amplifier having a pair of inputs, one of which is connected to a point of reference potential, and c. a feedback circuit from the output of said amplifier to an input thereof having a plurality of separate feedback paths each including a different one of said sources and the gate circuit therefor in series therein, each of said paths having a connection between a different one of said sources and the output of said amplifier via said gate circuit therefor, and means for connecting the other of said pair of amplifier inputs to said one terminal of said last named source.
Claim 3
Dependent Claim
33 words
The invention as set forth in claim 1 wherein said amplifier is an operational amplifier, said other input being the direct input thereof, and said one input being the inverting direct input thereof.
Claim 4
Dependent Claim
55 words
The invention as set forth in claim 2 including a capacitor connected to said feedback path between said inverting input of said amplifier and said other terminals of said sources and means for applying pulses through said capacitor immediately prior to operation of each of said gate circuits from its open to its closed condition.
Claim 5
Dependent Claim
160 words
A multiplexing system for providing successive samples of the voltage output produced by a multiplicity of analog sources each having an output terminal and a return terminal, said system comprising a. a multiplexing of first gates each corresponding to a different one of said sources and connected in series therewith to the output terminal thereof, b. an operational amplifier having output, direct input and inverting input terminals, c. a plurality of second gates, d. said series connected sources being connected to said output terminal of said amplifier via said first gates, and said return terminals being connected to said inverting terminal of said amplifier via said second gates, e. said direct terminal of said amplifier being connected to the point of reference potential, the potential of said return terminals and said point of refereNce potential being driven to virtually equal potential by the regulation of the amplifier feedback network, and f. said samples being provided at said amplifier output terminal.
Claim 6
Dependent Claim
160 words
A multiplexing system for providing successive samples of the voltage output produced by a multiplicity of analog sources each having an output terminal and a return terminal, said system comprising a. a multiplexing of first gates each corresponding to a different one of said sources and connected in series therewith to the output terminal thereof, b. an operational amplifier having output, direct input and inverting input terminals, c. a plurality of second gates, d. said series connected sources being connected to said output terminal of said amplifier via said first gates, and said return terminals being connected to said inverting terminal of said amplifier via said second gates, e. said direct terminal of said amplifier being connected to the point of reference potential, the potential of said return terminals and said point of refereNce potential being driven to virtually equal potential by the regulation of the amplifier feedback network, and f. said samples being provided at said amplifier output terminal.
Claim 7
Dependent Claim
23 words
The invention as set forth in claim 4 including a third gate connected between said point of reference potential and said inverting terminal.
Claim 8
Dependent Claim
127 words
The invention as set forth in claim 4 wherein said series connected first gates and sources are connected in parallel with each other in a plurality of groups, each corresponding to a different one of said second gates such that the return terminals of the sources in different ones of said groups are connected to each other and the output sides of each of said first gates in said different ones of said groups are connected to each other, said output sides of said gates in each of said groups being connected to said amplifier output, and said connected return terminals of said sources in each of said groups being connected via the one of said second gates corresponding thereto to said inverting terminal of said amplifier.
Claim 9
Dependent Claim
32 words
The invention as set forth in claim 6 including a capacitor, and a source of neutralizing pulses connected to the connection between said return terminals and said inverting terminal via said capacitor.
Claim 10
Dependent Claim
61 words
The invention as set forth in claim 7 wherein said first gates are three terminal active devices having input, output and control terminals, said input terminals each being connected to said sources and said output terminals providing said output sides, and wherein said capacitor has a value of capacitance approximately equal to the inter-electrode capacitance between said input and control terminals.
Claim 11
Dependent Claim
51 words
The invention as set forth in claim 6 including a plurality of fourth gates each corresponding to a different one of said groups, said output sides of said first gates in different ones of said groups being connected via the one of said fourth gates corresponding thereto to said amplifier output.
Claim 12
Dependent Claim
55 words
The invention as set forth in claim 7 wherein said second gates equal said first gate in number and each of said second gates also corresponds to a different one of said first gates, said return terminals of said sources each being connected via its corresponding second gate to said inverting inputs of said amplifier.
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) | 1975-05-23 | 1975-11-22 | 1976-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-23 | 1979-11-22 | 1980-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-23 | 1983-11-22 | 1984-05-23 | $7700.00 | Window Closed / Lapsed |