US3867711A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Swimmer detection system for remote or local deployment
Assignee: Individual
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Filing: 1973-06-25
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Granted: 1975-02-18
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Expires: 1993-06-25
Abstract
Abstract A swimmer detection system and method which tests a remotely produced acoustic signal for frequency components in the range of the human heart beat rate. The received signal is tested by correlating a sample of the signal with a successively received segment of the signal. Good correlation signifies that the sample signal and successive segment of the signal are periodic and have components of the same frequency and hence the presence of a swimmer is likely.
Inventors
- 👤 Paul V Ruscus
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:25
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/02; A61B5/024
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
198 words
A swimmer detection system comprising: mechanical to electrical transducing means for receiving an acoustic signal; means for recording a sample of said acoustic signal, said recording means having an output for reproducing the recorded sample of said acoustic signal; means for correlating the recorded sample of said signal with a segment of said acoustic signal received successively to said recorded sample, said correlating means being operative to produce an output when said recorded sample and the successively received segment of said signal are periodic and of substantially the same frequency; switching means having at least two operative positions, a first position for connecting said transducing means to said recording means and a second position for connecting said transducing means to a first input of said correlating means and for changing the state of said recording means from record to reproduce, said recording means reproduce output being connected to a second input of said correlating means, whereby the recorded sample of said signal and the successively received segment of said signal are correlated; and timing means connected to said switching means for automatically changing the position of said switching means from its said first position to said second position.
Claim 2
Dependent Claim
198 words
A swimmer detection system comprising: mechanical to electrical transducing means for receiving an acoustic signal; means for recording a sample of said acoustic signal, said recording means having an output for reproducing the recorded sample of said acoustic signal; means for correlating the recorded sample of said signal with a segment of said acoustic signal received successively to said recorded sample, said correlating means being operative to produce an output when said recorded sample and the successively received segment of said signal are periodic and of substantially the same frequency; switching means having at least two operative positions, a first position for connecting said transducing means to said recording means and a second position for connecting said transducing means to a first input of said correlating means and for changing the state of said recording means from record to reproduce, said recording means reproduce output being connected to a second input of said correlating means, whereby the recorded sample of said signal and the successively received segment of said signal are correlated; and timing means connected to said switching means for automatically changing the position of said switching means from its said first position to said second position.
Claim 3
Dependent Claim
32 words
The system according to claim 1 wherein said timing means is further operative to return said switching means to said first position in the absence of an output from saiid correlating means.
Claim 4
Dependent Claim
55 words
The system according to claim 1 including a threshold level alarm circuit connected to the output of said correlating means, said circuit being actuated in response to an output of said correlating means having a magnitude equal to or greater than a predetermined threshold whereby said threshold indicates the presence of a swimmer is likely.
Claim 5
Dependent Claim
37 words
The system of claim 1 including: means for time delaying said recording in the absence of a correlation output indicative of the presence of the swimmer and recorrelating the recording with successive segments of said received signal.
Claim 6
Dependent Claim
32 words
The system of claim 4, including: a bandpass filter connected between said transducing means and said recording means for passing frequency components in the range of those produced by a human heart.
Claim 7
Independent Claim
116 words
A method for detecting a swimmer comprising: receiving a remotely produced acoustic signal; recording a sample of said received signal on a recorder; correlating the recorded sample signal with an acoustic signal received successively to said recorded sample signal; comparing the correlated signal with a predetermined threshold level, the magnitude of said level indicating the presence of a swimmer; incrementally delaying said recorded sample signal in the absence of a correlated signal level above said predetermined threshold; recorrelating the incrementally delayed recorded sample with successively received acoustic signals until the correlated signal level exceeds said threshold level; and erasing said recorded sample if said correlated signal level has a magnitude less than said predetermined threshold level.
Claim 8
Independent Claim
116 words
A method for detecting a swimmer comprising: receiving a remotely produced acoustic signal; recording a sample of said received signal on a recorder; correlating the recorded sample signal with an acoustic signal received successively to said recorded sample signal; comparing the correlated signal with a predetermined threshold level, the magnitude of said level indicating the presence of a swimmer; incrementally delaying said recorded sample signal in the absence of a correlated signal level above said predetermined threshold; recorrelating the incrementally delayed recorded sample with successively received acoustic signals until the correlated signal level exceeds said threshold level; and erasing said recorded sample if said correlated signal level has a magnitude less than said predetermined threshold level.
Claim 9
Dependent Claim
30 words
The method of claim 6, wherein said delaying step includes the step of successively delaying the recording one-tenth of the period of the lowest frequency expected from the signal source.
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) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |