US3824588A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Analog to digital converter having digital offset correction
Assignee: United States Department of the Navy
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Filing: 1973-02-09
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Granted: 1974-07-16
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Expires: 1993-02-09
Abstract
Abstract An analog to digital converter digitizes incoming analog signals and also corrects the digitized value for zero baseline offset. The converter is a ripple counter using an inverted resistor ladder network. The output of the ladder network is compared with the incoming analog signal for equality. When equality is sensed the counter is stopped. Offset correction is performed by digitizing a zero level analog signal, determining the error, and storing the error in a register. The stored value of the error is added or subtracted arithmetically to subsequent conversions.
Inventors
- 👤 R Vermillion
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:02
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/50
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
160 words
An analog to digital converter comprising: a ripple counter; a ladder network coupled to the output of said counter; a voltage comparator coupled to the output of said ladder network for comparing the analog output of said network with the analog signal to be digitized and for producing an inhibiting signal to said counter when said ladder network output and said analog signal are equal, whereby said counter retains said digitized analog signal; and a zero offset correction network coupled to the output of said counter for digitally modifying said digitized analog signal in said network to its correct value; said zero offset correction network comprising: a plurality of storage devices, one storage device coupled to a respective one of the outputs of said counter, said storage devices being clocked to accept and store a digital signal only when digital zero is measured; and a plurality of full adders to add said stored digital signal to a digitized analog signal.
Claim 2
Dependent Claim
160 words
An analog to digital converter comprising: a ripple counter; a ladder network coupled to the output of said counter; a voltage comparator coupled to the output of said ladder network for comparing the analog output of said network with the analog signal to be digitized and for producing an inhibiting signal to said counter when said ladder network output and said analog signal are equal, whereby said counter retains said digitized analog signal; and a zero offset correction network coupled to the output of said counter for digitally modifying said digitized analog signal in said network to its correct value; said zero offset correction network comprising: a plurality of storage devices, one storage device coupled to a respective one of the outputs of said counter, said storage devices being clocked to accept and store a digital signal only when digital zero is measured; and a plurality of full adders to add said stored digital signal to a digitized analog signal.
Claim 3
Dependent Claim
23 words
An A/D converter as recited in claim 1 wherein: said storage devices comprise flip flops and said addition is in two''s complement addition.
References Cited (Backward Citations)
US3445839A
Cited
US3550114A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-15 | 1978-01-14 | 1978-07-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-15 | 1982-01-14 | 1982-07-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-15 | 1986-01-14 | 1986-07-16 | $7700.00 | Window Closed / Lapsed |