US3600688A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Signal discriminator circuit
Assignee: Bethlehem Steel Corp
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Filing: 1970-04-21
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Granted: 1971-08-17
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Expires: 1990-04-21
Abstract
Abstract A circuit, for eddy current testing of steel shapes, which discriminates input pulses caused by severe defects from input pulses caused by minor defects as well as pulses caused by changes in the properties of the shapes. The circuit discriminates input pulses greater than a minimum amplitude and less than a maximum width from other pulses.
Inventors
- 👤 Robert C Booth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 21:24
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/72; G01N27/82; G01N27/90; G01N27/9046
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
159 words
A circuit for discriminating an input pulse of greater than a minimum amplitude and less than a maximum width from other pulses, comprising: a. means for producing a first signal at the peak amplitude of said input pulse; b. means for producing a second signal at the time the amplitude of said input pulse has decreased by a predetermined extent from its peak value; c. means responsive to said first signal for producing a third signal for a predetermined period after the peak of said input pulse; d. means for producing a fourth signal only when the amplitude of said input pulse equals or exceeds a minimum magnitude, said fourth signal beginning at the time said minimum amplitude is equalled and lasting until the end of said third signal; and e. means for producing a fifth signal only when: (1) said second signal is produced during the period of said third signal; and (2) there is a fourth signal.
Claim 2
Dependent Claim
159 words
A circuit for discriminating an input pulse of greater than a minimum amplitude and less than a maximum width from other pulses, comprising: a. means for producing a first signal at the peak amplitude of said input pulse; b. means for producing a second signal at the time the amplitude of said input pulse has decreased by a predetermined extent from its peak value; c. means responsive to said first signal for producing a third signal for a predetermined period after the peak of said input pulse; d. means for producing a fourth signal only when the amplitude of said input pulse equals or exceeds a minimum magnitude, said fourth signal beginning at the time said minimum amplitude is equalled and lasting until the end of said third signal; and e. means for producing a fifth signal only when: (1) said second signal is produced during the period of said third signal; and (2) there is a fourth signal.
Claim 3
Dependent Claim
39 words
A circuit as recited in claim 1, in which means a. comprises a differentiator having an input terminal to which said input pulse is supplied, and a zero crossover detector to which the output of said differentiator is supplied.
Claim 4
Dependent Claim
80 words
A circuit as recited in claim 2, in which means b. comprises: i. a sample-and-hold circuit having a first input terminal to which said input pulse is supplied, and a second input terminal connected to the output of said zero crossover detector; and ii. a voltage divider network connected to the output of said sample-and-hold circuit. ii. a voltage divider network connected to the and more particularly to phase difference detectors for detecting phase difference between two similar wave trains.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-16 | 1975-02-15 | 1975-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-16 | 1979-02-15 | 1979-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-16 | 1983-02-15 | 1983-08-17 | $7700.00 | Window Closed / Lapsed |