US4774499A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Analog to digital converter
Assignee: Plessey Semiconductors Ltd
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Filing: 1987-01-29
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Granted: 1988-09-27
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Expires: 2007-01-29
Abstract
Abstract A converter of the flash type includes means for amplifying and d.c. level shifting portions of the input analog waveform fed to each A to D converter unit to provide each converter unit with a full voltage input swing relative to the reference voltage for conversion, thereby producing a more accurate digital output.
Inventors
- 👤 David B. Mapleston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:09
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/06; H03M1/0617; H03M1/0675; H03M1/12; H03M1/34; H03M1/36; H03M1/361
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
152 words
An analogue to digital flash converter comprising: signal prescaling means, responsive to an analogue input signal, said means being such as to provide a set of analogue electrical signals, each such signal, within limits, being linearly dependant upon the voltage amplitude of said input signal, each thus related thereto by a common amplification factor and by a different d.c. voltage offset; a single-flash conversion stage comprised of: a set of like analogue to digital converter units, each unit having a set of binary outputs and at least one carry output, all units being configured in parallel and referred to a common reference voltage, and, each unit being co-operative with said prescaling means to receive a corresponding one of said electrical signals; and, signal encoding means, co-operative with the binary and carry outputs of each said unit, and to derive therefrom electrical digital signals indicative of the voltage amplitude of said input signal.
Claim 2
Dependent Claim
152 words
An analogue to digital flash converter comprising: signal prescaling means, responsive to an analogue input signal, said means being such as to provide a set of analogue electrical signals, each such signal, within limits, being linearly dependant upon the voltage amplitude of said input signal, each thus related thereto by a common amplification factor and by a different d.c. voltage offset; a single-flash conversion stage comprised of: a set of like analogue to digital converter units, each unit having a set of binary outputs and at least one carry output, all units being configured in parallel and referred to a common reference voltage, and, each unit being co-operative with said prescaling means to receive a corresponding one of said electrical signals; and, signal encoding means, co-operative with the binary and carry outputs of each said unit, and to derive therefrom electrical digital signals indicative of the voltage amplitude of said input signal.
Claim 3
Dependent Claim
58 words
A flash converter, as claimed in claim 1, wherein said signal prescaling means is comprised of: a set of linear operational amplifiers, each matched in gain, and, together equal in number to the number of said units; and, offset voltage source means, co-operative with each said amplifier, to supply to the subtractive input thereof a different offset voltage.
Claim 4
Dependent Claim
30 words
A flash converter, as claimed in claim 2, wherein said source means comprises: a voltage source, source of said common reference voltage; and, a voltage divider referred to said source.
Claim 5
Dependent Claim
60 words
A flash converter, as claimed in claim 3, namely an 8-bit converter, wherein; the amplifiers and the units are each four in number; the amplifiers provide four-fold amplification; the units are capable of resolving 6-bits each; and, the voltage divider is comprised of five resistance elements connected in series, the resistance values of which are in a ratio of:1/2:1:1:1:1/2, respectively.
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) | 1991-09-27 | 1992-03-28 | 1992-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-27 | 1996-03-28 | 1996-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-27 | 2000-03-28 | 2000-09-27 | $7700.00 | Window Closed / Lapsed |