US3646506A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sonic detection apparatus
Assignee: United States Department of the Navy
•
Filing: 1970-04-09
•
Granted: 1972-02-29
•
Expires: 1990-04-09
Abstract
Abstract An improved swimmer and floater detector having a sonic generator and receiver and a shift detector indicating the doppler frequency difference between the generated and received sonic waves within a guarded volume of flowing water. The shift detector output is passed to a plurality of adjacent narrow bandpass filters, each being connected via a respective gaincontrolled amplifier to a common multiple frequency meter. The amplifier gain control is nonproportional to the output amplitude and is operative in two modes to steadily increase or decrease the gain when the output is below or above threshold respectively.
Inventors
- 👤 Henry Suter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:02
CPC Classifications
G; G01; G01S; G01S15/00; G01S15/02; G01S15/50; G01S15/52; G01S15/523; G01S13/00; G01S13/02; G01S13/50; G01S13/52; G01S13/56; Y; Y10; Y10S; Y10S367/00; Y10S367/90
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
189 words
A doppler sonar detection apparatus of the type comprising an acoustic generator, an acoustic receiver, a doppler shift detector which compares the frequency of the generated waves with that of the received waves and produces an output indicative of the doppler shift, and a plurality of bandpass filters operatively connected in parallel to the shift detector for passing respective bandwidths of the shift detector output, wherein the improvement comprises a plurality of control circuits, each one of which is connected to a corresponding one of the bandpass filters and includes: a voltage-controlled, variable gain amplifier having two input terminals one of which is connected to a corresponding filter for amplifying the output thereof; level detector means connected to receive the amplifier output for providing a voltage at a first output terminal when the amplifier output is below a first predetermined level; and gain compensator means connected to the level detector first output terminal for providing a continuously increasing or decreasing voltage to control the amplifier gain when the amplifier output is respectively below or above the first level, the compensator means being connected to the other amplifier input terminal.
Claim 2
Dependent Claim
189 words
A doppler sonar detection apparatus of the type comprising an acoustic generator, an acoustic receiver, a doppler shift detector which compares the frequency of the generated waves with that of the received waves and produces an output indicative of the doppler shift, and a plurality of bandpass filters operatively connected in parallel to the shift detector for passing respective bandwidths of the shift detector output, wherein the improvement comprises a plurality of control circuits, each one of which is connected to a corresponding one of the bandpass filters and includes: a voltage-controlled, variable gain amplifier having two input terminals one of which is connected to a corresponding filter for amplifying the output thereof; level detector means connected to receive the amplifier output for providing a voltage at a first output terminal when the amplifier output is below a first predetermined level; and gain compensator means connected to the level detector first output terminal for providing a continuously increasing or decreasing voltage to control the amplifier gain when the amplifier output is respectively below or above the first level, the compensator means being connected to the other amplifier input terminal.
Claim 3
Dependent Claim
38 words
The detection apparatus of claim 1 wherein: the compensator means includes an RC circuit connected to the level detector first output terminal and receiving charging voltage therefrom, the RC circuit being connected to the other amplifier input terminal.
Claim 4
Dependent Claim
32 words
The detection apparatus of claim 2 wherein: the RC circuit includes a capacitor connected in series through a junction to a resistor, the junction being connected to the other amplifier input terminal.
Claim 5
Dependent Claim
37 words
The detection apparatus of claim 2 wherein: the level detector includes a second output terminal adapted to be connected to an external alarm for supplying voltage thereto when the amplifier output is above a second predetermined level.
Claim 6
Dependent Claim
115 words
The detection apparatus of claim 4 wherein: the level detector comprises a meter having a pointer member whose displacement along a path corresponds to the level of the amplifier output, a voltage source connected to the pointer member, and first and second contact members located in the path at respective first and second positions corresponding respectively to the first and second predetermined levels, the first and second contact members being connected respectively to the first and second output terminals of the level detector, whereby voltage is supplied to the RC circuit or to the level detector second output terminal when the pointer member is in contact with the first or the second contact member respectively.
Claim 7
Dependent Claim
112 words
The detection apparatus of claim 4 wherein: the level detector comprises first and second voltage reference sources corresponding respEctively to the first and second predetermined levels, a first comparator means connected to the amplifier and receiving the output thereof and connected to the first reference source for providing the voltage at the first output terminal of the level detector when the amplifier output is below the first predetermined level, and a second comparator means connected to the amplifier and receiving the output thereof and connected to the second reference source for providing the voltage at the second output terminal of the level detector when the amplifier output exceeds the second predetermined level.
Claim 8
Dependent Claim
87 words
The detection apparatus of claim 4 wherein the improvement further comprises: modulation means connected to each control circuit and operatively receiving the output of each amplifier therein for mixing the amplifier outputs with a secondary signal to form a composite signal having a plurality of frequencies, the frequency of the secondary signal being higher than the frequencies of the amplifier outputs; and a frequency meter connected to the modulation means and receiving the output thereof for simultaneously displaying the plurality of frequencies represented in the composite signal.
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) | 1975-02-28 | 1975-08-30 | 1976-02-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-28 | 1979-08-30 | 1980-02-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-28 | 1983-08-30 | 1984-02-29 | $7700.00 | Window Closed / Lapsed |