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US3772699A
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Radio navigation pulse pair detector
Assignee: Raytheon Co
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Filing: 1972-08-23
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Granted: 1973-11-13
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Expires: 1992-08-23
Abstract
Abstract In a radio navigation system responding to an interrogation pulse pair there must be a reliable determination of when the system receiver is being interrogated by an aircraft, preferably without decreasing the receiver sensitivity. A radio navigation system of the type described receives a pair of interrogation pulses which are decoded into a single pulse for operation of a reply transmitter. An interrogation pulse pair detector decodes the interrogation pulses only during the active time span thereof by first amplifying and detecting the pulse level. A negative clipper circuit responds to the amplified pulse pair and is adjusted to blank-out that portion of the amplifier output signal below a preset level. This eliminates the system blanking pulses present in some systems, as well as most low level noise pulses. The clipped interrogation pulses are applied to a modified correlator wherein they are multiplied together by passing one pulse through a delay line and integrating the output pulse. The integrated pulse is applied to a comparator for generating a single decoded pulse when the modified correlator output exceeds a reference level. The transmitter generates position determining signals in response to the single decoded pulse.
Inventors
- 👤 G Romrell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:36
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/74; G01S13/76; G01S13/78; G01S13/785; G01S13/788
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
100 words
A spaced pulse pair detector, comprising in combination: amplifier means for receiving at an input thereto the spaced pulse pair and having means for biasing the output signal thereof to a preset level, a clipping circuit connected to the output of said amplifier means for limiting an output thereof to above the preset level, correlator means responsive to the output of said clipping circuit and having an output varying iN accordance with a multiplication of the pulse pair, and means for detecting when the output of said correlating means exceeds an established level and generating a detection signal related thereto.
Claim 2
Dependent Claim
100 words
A spaced pulse pair detector, comprising in combination: amplifier means for receiving at an input thereto the spaced pulse pair and having means for biasing the output signal thereof to a preset level, a clipping circuit connected to the output of said amplifier means for limiting an output thereof to above the preset level, correlator means responsive to the output of said clipping circuit and having an output varying iN accordance with a multiplication of the pulse pair, and means for detecting when the output of said correlating means exceeds an established level and generating a detection signal related thereto.
Claim 3
Dependent Claim
54 words
A spaced pulse pair detector as set forth in claim 1 wherein said correlator means includes: a multiplier for generating an output signal related to a multiplication of the two input signals thereto, and delay means connected to one input of said multiplier for introducing a time delay into one signal to said multiplier.
Claim 4
Dependent Claim
27 words
A spaced pulse pair detector as set forth in claim 2 wherein the time delay introduced by said delay means equal the spacing between the pulse pair.
Claim 5
Dependent Claim
35 words
A spaced pulse pair detector as set forth in claim 2 wherein said correlator means further includes an integrator connected to the output of said multiplier and having an output varying as a ramp function.
Claim 6
Dependent Claim
30 words
A spaced pulse pair detector as set forth in claim 1 including means for adjusting the preset level of said means for biasing the output signal of said amplifier means.
Claim 7
Dependent Claim
24 words
A spaced pulse pair detector as set forth in claim 5 wherein said clipping circuit includes means for adjusting the level of output limiting.
Claim 8
Dependent Claim
139 words
In a radio navigation system, a station for receiving signals consisting of pulse pairs and for responding thereto, comprising: means for receiving said pulse pair, and a pulse pair detector connected to said means and generating an interrogation signal when said means receives a pulse pair, including: amplifier means for receiving at an input thereof the spaced pulse pair and having means for biasing the output signal thereof to a preset level, a clipping circuit connected to the output of said amplifier means for limiting an output thereof to above a preset level, correlator means responsive to the output of said clipping circuit and having an output varying in accordance with a multiplication of the pulse pair, and means for detecting when the output of said correlator means exceeds an established level and generating a detection signal related thereto.
Claim 9
Dependent Claim
139 words
In a radio navigation system, a station for receiving signals consisting of pulse pairs and for responding thereto, comprising: means for receiving said pulse pair, and a pulse pair detector connected to said means and generating an interrogation signal when said means receives a pulse pair, including: amplifier means for receiving at an input thereof the spaced pulse pair and having means for biasing the output signal thereof to a preset level, a clipping circuit connected to the output of said amplifier means for limiting an output thereof to above a preset level, correlator means responsive to the output of said clipping circuit and having an output varying in accordance with a multiplication of the pulse pair, and means for detecting when the output of said correlator means exceeds an established level and generating a detection signal related thereto.
Claim 10
Dependent Claim
34 words
In a radio navigation system as set forth in claim 7 wherein the means for biasing in said amplifier means includes means for adjusting the preset level of the bias of said amplifier means.
Claim 11
Dependent Claim
24 words
In a radio navigation system as set forth in claim 8 wherein said clipping circuit includes means for adjusting the level of output limiting.
Claim 12
Dependent Claim
54 words
In a radio navigation system as set forth in claim 7 wherein said correlator means includes: a multiplier for generating an output signal related to a multiplication of the two input signals thereto, and delay means connected to one input of said multiplier for introducing a time delay into one signal to said multiplier.
Claim 13
Dependent Claim
35 words
In a radio navigation system as set forth in claim 10 wherein said correlator means further includes an integrator connected to the output of said multiplier and having an output varying as a ramp function.
Claim 14
Dependent Claim
46 words
In a radio navigation system as set forth in claim 7 wherein said means for detecting includes a comparator for comparing a reference level to the output of said correlator means and generating a detection pulse signal when the correlator means output exceeds the reference level.
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) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |