Patent US3641485A successfully refreshed from Google Patents.
US3641485A
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Echo simulation means
Assignee: United States Department of the Navy
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Filing: 1970-05-25
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Granted: 1972-02-08
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Expires: 1990-05-25
Abstract
Abstract Synthetic sonar echoes are generated in response to a sonar signal by utilizing a delay line, time compression technique to generate a reconstructed waveform which is then sampled to provide a pulsed input to a shift register means having taps spaced therealong corresponding to structural highlight positions along a target. The shift register is caused to serve as a variable delay line by varying the sampling and shift rate in response to aspect angle as determined by phase-sensitive logic means. The taps feed a network of attenuators and filters which produce across an output resistor an electrical signal which can be amplified and used to drive a sound projector to produce the desired simulated echo.
Inventors
- 👤 Francis J Murphree
- 👤 Michael T Marrero
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:37
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/52; G01S7/52004
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
236 words
Apparatus for generating aspect-dependent simulated echoes from targets having a relatively large length to diameter ratio in response to an insonifying pulse, comprising: read-in and readout means operative to provide a delayed signal representative to said insonifying pulse; variable rate sampler means connected to said read-in readout means and operative to sample said delayed signal in response to a sample rate signal having a frequency f1 and to provide output pulse data representative of said delayed signal; shift register means connected to receive the output of said variable rate sampler means and to advance said data at a shift rate equal to f1; a plurality of outputs derived from selected stages along said shift register means; a plurality of bow aspect gates, each connected to one of said outputs; a plurality of stern aspect gates, each connected to one of said outputs; phase detector means responsive to said insonifying signal to provide an output representative of target aspect and operative to enable selected ones of said gates, depending upon the aspect of the target; means, responsive to the output of said phase detector means, for generating said sample rate and shift rate signal at a frequency f1 which varies as a function of target aspect angle; and echo-synthesizing means comprising a plurality of attenuators connected to the outputs of said gates and connected to summing means whereby a simulated echo signal having predetermined highlights is synthesized.
Claim 2
Dependent Claim
236 words
Apparatus for generating aspect-dependent simulated echoes from targets having a relatively large length to diameter ratio in response to an insonifying pulse, comprising: read-in and readout means operative to provide a delayed signal representative to said insonifying pulse; variable rate sampler means connected to said read-in readout means and operative to sample said delayed signal in response to a sample rate signal having a frequency f1 and to provide output pulse data representative of said delayed signal; shift register means connected to receive the output of said variable rate sampler means and to advance said data at a shift rate equal to f1; a plurality of outputs derived from selected stages along said shift register means; a plurality of bow aspect gates, each connected to one of said outputs; a plurality of stern aspect gates, each connected to one of said outputs; phase detector means responsive to said insonifying signal to provide an output representative of target aspect and operative to enable selected ones of said gates, depending upon the aspect of the target; means, responsive to the output of said phase detector means, for generating said sample rate and shift rate signal at a frequency f1 which varies as a function of target aspect angle; and echo-synthesizing means comprising a plurality of attenuators connected to the outputs of said gates and connected to summing means whereby a simulated echo signal having predetermined highlights is synthesized.
Claim 3
Dependent Claim
63 words
Apparatus as defined in claim 1, and wherein: said shift register means comprises N stages, where N is approximately equal to an integral multiple of the time that would be required for sound to propagate in a supporting medium from one end of a simulated target to the other end and return, divided by the maximum sampling period of said variable rate sampler.
Claim 4
Dependent Claim
199 words
Apparatus as defined in claim 1, and wherein said means for generating said sample and shift rate signals at frequency f1 comprises: phase detector means operative to provide an output signal representativE of simulated target aspect angle; local oscillator means providing signals at frequency f2; count and hold circuit means; gate means connected to receive said local oscillator signal and responsive to the output of said phase detector means to pass said local oscillator signals to said count and hold circuit; counter means responsive to the outputs of said phase detector means and said local oscillator to apply an inhibit signal to said gate means after a predetermined number ''''i'''' of cycles of said oscillator output have been passed to said count and hold circuit; a multiple circuit responsive to said local oscillator and operative to provide an output frequency which is a predetermined multiple of f2; second counter means for counting the output cycles of said multiplier circuit; and comparator means responsive to each occurrence of an equality of count between said count and hold circuit and said second counter means to provide an output signal, the output signals of said comparator means occurring at said frequency f1.
Claim 5
Dependent Claim
19 words
Apparatus as defined in claim 1, and wherein: each of said plurality of attenuators comprises a low-pass filter means.
Claim 6
Dependent Claim
119 words
Apparatus as defined in claim 1, and wherein said read-in and readout means comprises: means for receiving said insonifying pulse and providing a signal representative thereof; sampler means operative to periodically sample said insonifying pulse and to provide an output of data samples; delay line, time compressor means including recirculation means operative to group said samples in time-compressed form; a signal reconstruction network; and means for providing a delayed readout of said data samples at a real time rate to said signal reconstruction network; said readout being initiated at a predetermined time after cessation of said insonifying pulse; said signal reconstruction network being operative to combine the data sample readout into said delayed signal representative of said insonifying pulse.
Claim 7
Dependent Claim
199 words
Apparatus as defined in claim 2, and wherein said means for generating said sample and shift rate signals at frequency f1 comprises: phase detector means operative to provide an output signal representative of simulated target aspect angle; local oscillator means providing signals at frequency f2; count and hold circuit means; gate means connected to receive said local oscillator signal and responsive to the output of said phase detector means to pass said local oscillator signals to said count and hold circuit; counter means responsive to the outputs of said phase detector means and said local oscillator to apply an inhibit signal to said gate means after a predetermined number ''''i'''' of cycles of said oscillator output have been passed to said count and hold circuit; a multiplier circuit responsive to said local oscillator and operative to provide an output frequency which is a predetermined multiple of f2; second counter means for counting the output cycles of said multiplier circuit; and comparator means responsive to each occurrence of an equality of count between said count and hold circuit and said second counter means to provide an output signal, the output signals of said comparator means occurring at said frequency f1.
Claim 8
Dependent Claim
119 words
Apparatus as defined in claim 6, and wherein said read-in and readout means comprises: means for receiving said insonifying pulse and providing a signal representative thereof; sampler means operative to periodically sample said insonifying pulse and to provide an output of data samples; delay line, time compressor means including recirculation means operative to group said samples in time-compressed form; a signal reconstruction network; and means for providing a delayed readout of said data samples at a real time ratio to said signal reconstruction network, said reaDout being initiated at a predetermined time after cessation of said insonifying pulse; said signal reconstruction network being operative to combine the data sample readout into said delayed signal representative of said insonifying pulse.
Claim 9
Dependent Claim
19 words
Apparatus as defined in claim 7, and wherein: each of said plurality of attenuators comprises a low-pass filter means.
References Cited (Backward Citations)
US3180295A
Cited
US3555165A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-02-07 | 1975-08-09 | 1976-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-07 | 1979-08-09 | 1980-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-07 | 1983-08-09 | 1984-02-08 | $7700.00 | Window Closed / Lapsed |