US4075703A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recursive filter mean-level detector
Assignee: United States Department of the Navy
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Filing: 1976-11-01
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Granted: 1978-02-21
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Expires: 1996-11-01
Abstract
Abstract An apparatus for estimating the mean level of a stochastic process such asould be observed at the output of a radar, communications, or sonar receiver and for using the mean level to provide a threshold with which possible signal samples are compared to determine the presence or absence of the signal. The estimated mean level is used in lieu of a priori information when it is unreasonable to assume that the characteristics of the stochastic process are known. A first order recursive filter receives signal samples and provides an output which is proportional to the mean of the stochastic process. The output of the first order recursive filter Y n is multiplied by the factor T such that the product TY n is a threshold quantity which is compared with the input signal samples X n . When X n exceeds TY n an output is indicated.
Inventors
- 👤 George M. Dillard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:06
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/02; G01S7/28; G01S7/285; G01S7/292; G01S7/2923; G01S7/2927
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
118 words
A device for calculating the mean level of a stochastic process and for using the mean level to provide a threshold for determining the presence or absence of a signal comprising: first means for outputting sample values X n of a detected signal; a first order recursive filter connected to the output of said first means for providing output values Y n proportional to the mean value of said stochastic process; second means connected to said first order recursive filter for forming the products TY n where T is a predetermined value; and third means for comparing the values TY n with said values X n and for providing an output when X n ≧ TY n .
Claim 2
Independent Claim
118 words
A device for calculating the mean level of a stochastic process and for using the mean level to provide a threshold for determining the presence or absence of a signal comprising: first means for outputting sample values X n of a detected signal; a first order recursive filter connected to the output of said first means for providing output values Y n proportional to the mean value of said stochastic process; second means connected to said first order recursive filter for forming the products TY n where T is a predetermined value; and third means for comparing the values TY n with said values X n and for providing an output when X n ≧ TY n .
Claim 3
Dependent Claim
39 words
The device of claim 1 wherein said first order recursive filter comprises: a summing circuit; a storage register connected to the output of said summing circuit; and a multiplier connected to said storage register and to said summing circuit.
Claim 4
Dependent Claim
25 words
The device of claim 2 wherein said first means comprises: an envelope detector; and an analogue-to-digital converter connected to the output of said envelope detector.
Claim 5
Dependent Claim
9 words
The device of claim 3 where T > 1.
Claim 6
Independent Claim
119 words
A device for calculating the mean level of a stochastic process and for using the mean level to provide a threshold for determining the presence or absence of a signal comprising: first means for outputting a waveform X(t) representing a detected signal; a first order recursive filter connected to the output of said first means for providing an output waveform Y(t) delayed from X(t) by a time delay T o and representing an estimate of the mean level of said stochastic process; second means connected to said first order recursive filter for forming the product TY(t) where T is a predetermined value; and third means for comparing X(t) with TY(t) and for providing an output when X(t) ≧ Y(t).
Claim 7
Independent Claim
119 words
A device for calculating the mean level of a stochastic process and for using the mean level to provide a threshold for determining the presence or absence of a signal comprising: first means for outputting a waveform X(t) representing a detected signal; a first order recursive filter connected to the output of said first means for providing an output waveform Y(t) delayed from X(t) by a time delay T o and representing an estimate of the mean level of said stochastic process; second means connected to said first order recursive filter for forming the product TY(t) where T is a predetermined value; and third means for comparing X(t) with TY(t) and for providing an output when X(t) ≧ Y(t).
Claim 8
Dependent Claim
38 words
The device of claim 5 wherein said first order recursive filter comprises: a summing circuit; a delay circuit connected to the output of said summing circuit; and a multiplier connected between said delay circuit and said summing circuit.
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) | 1981-02-20 | 1981-08-22 | 1982-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-20 | 1985-08-22 | 1986-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-20 | 1989-08-22 | 1990-02-21 | $7700.00 | Window Closed / Lapsed |