US3239831A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic switching apparatus
Assignee: International Business Machines Corp
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Filing: 1960-12-27
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Granted: 1966-03-08
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Expires: 1980-12-27
Abstract
No abstract record available.
Inventors
- 👤 Sherman G Francisco
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:07
CPC Classifications
H; H03; H03K; H03K3/00; H03K3/02; H03K3/04; H03K3/05; H03K3/06; H03K3/12; H03K17/00; H03K17/51; H03K17/54; H03M; H03M1/00; H03M1/12; H03M1/34
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
153 words
A DIGITAL-TO-ANALOG CONVERTER FOR CONVERTING A VALUE EXPRESSED IN A DIGITAL CODE HAVING PLURAL ORDERS OF SIGNIFICANCE INTO AN ANALOG SIGNAL, COMPRISING A FIRST SUMMING AMPLIFIER, A REFERENCE VOLTAGE SIGNAL, PLURAL PARALLEL IMPEDANCE PATHS FOR APPLYING SAID REFERENCE VOLTAGE SIGNAL TO SAID FIRST SUMMING AMPLIFIER, THE NUMBER OF PARALLEL IMPEDANCE PATHS CORRESPONDING TO THE NUMBER OF ORDERS OF SIGNIFICANCE USED TO DEFINE THE DIGITAL INFORMATION TO BE CONVERTED, THE IMPEDANCE OF EACH OF SAID PARALLEL PATHS BEING WEIGHTED IN ACCORDANCE WITH THE DIGITAL CODE BEING USED, A BISTABLE ELECTRONIC SWITCH ASSOCIATED WITH EACH PARALLEL PATH HAVING A CLOSED AND OPEN SWITCH MODE OF OPERATION, EACH OF SAID BISTABLE ELECTRONIC SWITCHES BEING CONNECTED ITS CORRESPONDING PARALLEL PATH AND GROUND SO THAT IT MAY ALTERNATELY GROUND OR ISOLATE SAID PARALLEL PATH FROM SIGNAL GROUND IN ACCORDANCE WITH THE INSTANTANEOUS DIGITAL INFORMATION TO BE CONVERTED, SAID BISTABLE ELECTRONIC SWITCH PRESENTING A VERY LOW IMPEDANCE BETWEEN ITS
Claim 2
Dependent Claim
153 words
A DIGITAL-TO-ANALOG CONVERTER FOR CONVERTING A VALUE EXPRESSED IN A DIGITAL CODE HAVING PLURAL ORDERS OF SIGNIFICANCE INTO AN ANALOG SIGNAL, COMPRISING A FIRST SUMMING AMPLIFIER, A REFERENCE VOLTAGE SIGNAL, PLURAL PARALLEL IMPEDANCE PATHS FOR APPLYING SAID REFERENCE VOLTAGE SIGNAL TO SAID FIRST SUMMING AMPLIFIER, THE NUMBER OF PARALLEL IMPEDANCE PATHS CORRESPONDING TO THE NUMBER OF ORDERS OF SIGNIFICANCE USED TO DEFINE THE DIGITAL INFORMATION TO BE CONVERTED, THE IMPEDANCE OF EACH OF SAID PARALLEL PATHS BEING WEIGHTED IN ACCORDANCE WITH THE DIGITAL CODE BEING USED, A BISTABLE ELECTRONIC SWITCH ASSOCIATED WITH EACH PARALLEL PATH HAVING A CLOSED AND OPEN SWITCH MODE OF OPERATION, EACH OF SAID BISTABLE ELECTRONIC SWITCHES BEING CONNECTED ITS CORRESPONDING PARALLEL PATH AND GROUND SO THAT IT MAY ALTERNATELY GROUND OR ISOLATE SAID PARALLEL PATH FROM SIGNAL GROUND IN ACCORDANCE WITH THE INSTANTANEOUS DIGITAL INFORMATION TO BE CONVERTED, SAID BISTABLE ELECTRONIC SWITCH PRESENTING A VERY LOW IMPEDANCE BETWEEN ITS
References Cited (Backward Citations)
US2947971A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1969-03-07 | 1969-09-06 | 1970-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-03-07 | 1973-09-06 | 1974-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-03-07 | 1977-09-06 | 1978-03-08 | $7700.00 | Window Closed / Lapsed |