US4072949A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Range gate walk-off of compressive radar
Assignee: United States Department of the Navy
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Filing: 1970-03-17
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Granted: 1978-02-07
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Expires: 1990-03-17
Abstract
Abstract The invention involves an electronic countermeasure technique which is used against a pulse compression, random PRF, frequency diverse radar by stretching a pulse received from the radar before returning it. By progressively delaying the pulse until its delay is greater than the range gate of the radar, the return pulse to the radar is either blocked entirely or else it is received as a spurious, misleading echo.
Inventors
- 👤 LeRoy B. Van Brunt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 23:24
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/08; G01S13/10; G01S13/24; G01S7/00; G01S7/02; G01S7/38
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
101 words
A range gate walk off device to be used as a countermeasure to radar reception, comprising: input terminal means for receiving enemy radar signals; a plurality of traveling wave tubes connected in series to receive, modify and amplify the signals; delay means and gating means connected in series with each other and in parallel with one of the traveling wave tubes to comprise an RF memory loop; detection means, connected to the gating means, for detecting the received signals and opening the gating means when a signal is received; and output terminal means for transferring the modified signal to another device.
Claim 2
Dependent Claim
101 words
A range gate walk off device to be used as a countermeasure to radar reception, comprising: input terminal means for receiving enemy radar signals; a plurality of traveling wave tubes connected in series to receive, modify and amplify the signals; delay means and gating means connected in series with each other and in parallel with one of the traveling wave tubes to comprise an RF memory loop; detection means, connected to the gating means, for detecting the received signals and opening the gating means when a signal is received; and output terminal means for transferring the modified signal to another device.
Claim 3
Dependent Claim
75 words
The range gate walk off device of claim 1 wherein: the plurality of traveling wave tubes includes a first and a second traveling wave tube; an OFF gate is connected between the first and second traveling wave tubes; and a first one shot multivibrator is connected between said detection means and said OFF gate whereby the signal entering the second traveling wave tube will have a width determined by the period of said first multivibrator.
Claim 4
Dependent Claim
59 words
The range gate walk off device of claim 2 further including: a second one shot multivibrator connected to said detection means; and means connecting the second multivibrator to said gating means to turn on the RF memory loop so that oscillations will build up in the memory loop for a period determined by the period of the second multivibrator.
Claim 5
Dependent Claim
88 words
The range gate walk off device of claim 3 wherein: the plurality of traveling wave tubes includes a third traveling wave tube; a video range gate walk off generator is connected to said detection means to receive the detected true pulse width of the input signal, the generator operating to successively delay the input signal on a pulse to pulse basis; and an RF gate is connected between the second and third traveling wave tubes and connected to receive the output from the range gate walk off generator.
Claim 6
Dependent Claim
87 words
The range gate walk off device of claim 4 further including; a programmer sweep generator connected to receive the output of the range gate walk off generator; a serrodyne generator connected to receive the output of the programmer; an amplifier-inverter connected to receive the output of the serrodyne generator; and means connecting the output of the amplifier inverter with the helix of the third traveling wave tube whereby the output of the traveling wave tube varies in frequency as determined by the period of the serrodyne generator.
Claim 7
Dependent Claim
29 words
The range gate walk off device of claim 5 wherein the plurality of traveling wave tubes includes a fourth traveling wave tube connected to the third traveling wave tube.
Claim 8
Dependent Claim
143 words
The range gate walk off device of claim 6 further including; a coupler between the first traveling wave tube and the OFF gate; a power divider connected to receive one output from the coupler; a mixer connected to the power divider; a local oscillator connected to the mixer to heterodyne with the signal from the power divider; an IF amplifier connected to the output of the mixer; a discriminator connected to the IF amplifier; an amplifier connected to the discriminator; a slope detector connected to the amplifier; a sawtooth generator connected to the slope detector; and means connecting the output of the sawtooth generator with the helix of the fourth traveling wave tube so that the fourth traveling wave tube serrodynes at a frequency determined by the sawtooth generator and with an inverse polarity to the serrodyning of the third traveling wave tube.
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) | 1981-02-06 | 1981-08-08 | 1982-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-06 | 1985-08-08 | 1986-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-06 | 1989-08-08 | 1990-02-07 | $7700.00 | Window Closed / Lapsed |