US3665326A
Expired / Lapsed
US
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Automatic threshold detector with selectable percentage of threshold crossings
Assignee: United States Department of the Navy
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Filing: 1970-03-30
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Granted: 1972-05-23
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Expires: 1990-03-30
Abstract
Abstract An automatic threshold detector provides a variable-threshold correction voltage that allows a selectively predetermined percentage of an incoming signal to exceed a threshold voltage when the signal is sampled at a given rate. The detector generates a logic ''''one'''' for each crossing and a ''''zero'''' for each non-crossing of the threshold. The ''''one'''' and ''''zero'''' counts are then converted by digital techniques into a feedback correction voltage to maintain the selectively predetermined percentage of ''''ones'''' at the output.
Inventors
- 👤 Dean R Sullivan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 17:34
CPC Classifications
H; H03; H03K; H03K5/00; H03K5/01; H03K5/08
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
119 words
Automatic threshold correction apparatus for maintaining the percentage of crossings of a threshold voltage by an analog input signal constant comprising: means for sampling said input signal and for providing a digital decision for every crossing and a complementary digital decision for every non-crossing; means for producing a trigger pulse in response to every N crossings and in response to every M non-crossings wherein said percentage of crossings is equal to the ratio N/(N + M) X 100; means for producing directional control pulses in response to said digital decisions and said complementary digital decisions; and, up-down counter means for producing a feedback correction to said threshold voltage in response to said trigger pulses and said directional control pulses.
Claim 2
Dependent Claim
119 words
Automatic threshold correction apparatus for maintaining the percentage of crossings of a threshold voltage by an analog input signal constant comprising: means for sampling said input signal and for providing a digital decision for every crossing and a complementary digital decision for every non-crossing; means for producing a trigger pulse in response to every N crossings and in response to every M non-crossings wherein said percentage of crossings is equal to the ratio N/(N + M) X 100; means for producing directional control pulses in response to said digital decisions and said complementary digital decisions; and, up-down counter means for producing a feedback correction to said threshold voltage in response to said trigger pulses and said directional control pulses.
Claim 3
Dependent Claim
35 words
The apparatus of claim 1 wherein said means for sampling said input signal comprises analog-to-digital converter means and wherein said digital decisions comprises ''''one'''' logic levels and said complementary digital decisions comprise ''''zero'''' logic levels.
Claim 4
Dependent Claim
40 words
The apparatus of claim 1 wherein said means for producing said trigger pulses includes binary counter means in a first channel for counting said digital decisions and binary counter means in a second channel for counting said complementary digital decisions.
Claim 5
Dependent Claim
16 words
The apparatus of claim 3 wherein said binary counter means further include divisor selection switch means.
Claim 6
Dependent Claim
19 words
The apparatus of claim 1 further including digital-to-analog converter means coupled to the output of said up-down counter means.
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 |