US3719942A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Adaptive automatic gain control for radar systems
Assignee: Raytheon Co
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Filing: 1970-09-30
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Granted: 1973-03-06
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Expires: 1990-09-30
Abstract
Abstract An adaptive automatic gain control (AGC) system (also referred to as an adaptive sensitivity time control) is disclosed for pulsed radar applications to reduce the input dynamic range requirements to a doppler signal processor by forming a ''''running average'''' of a video signal along a range sweep over a succession of range bins and forming a ''''running average'''' over corresponding range elements of a large number of successive sweeps, where an element comprises one or more range bins. The resulting ''''running average'''' which constitutes a control function with a high degree of sweep-to-sweep stability because of the large amount of averaging is fed forward or back to an IF or other amplifier for gain control thereof.
Inventors
- 👤 E Herman
- 👤 Sullivan M O
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:06
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/02; G01S7/28; G01S7/285; G01S7/34; G01S13/00; G01S13/02; G01S13/50; G01S13/58; G01S13/64
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
70 words
In a radar system, apparatus for reducing the input dynamic range requirements to a signal processor, the combination comprising: means for reducing video signal amplitude in said radar system in response to an automatic gain control signal which exhibits a high degree of sweep-to-sweep stability; and means for generating said automatic gain control sigNal as a function of a running average of video return signals in both range and azimuth.
Claim 2
Dependent Claim
70 words
In a radar system, apparatus for reducing the input dynamic range requirements to a signal processor, the combination comprising: means for reducing video signal amplitude in said radar system in response to an automatic gain control signal which exhibits a high degree of sweep-to-sweep stability; and means for generating said automatic gain control sigNal as a function of a running average of video return signals in both range and azimuth.
Claim 3
Dependent Claim
70 words
In a radar system, apparatus for reducing the input dynamic range requirements to a signal processor, the combination comprising: means for reducing video signal amplitude in said radar system in response to an automatic gain control signal which exhibits a high degree of sweep-to-sweep stability; and means for generating said automatic gain control sigNal as a function of a running average of video return signals in both range and azimuth.
Claim 4
Dependent Claim
70 words
In a radar system, apparatus for reducing the input dynamic range requirements to a signal processor, the combination comprising: means for reducing video signal amplitude in said radar system in response to an automatic gain control signal which exhibits a high degree of sweep-to-sweep stability; and means for generating said automatic gain control sigNal as a function of a running average of video return signals in both range and azimuth.
Claim 5
Dependent Claim
147 words
In a pulsed radar system transmitting pulses during each of a plurality of range sweeps, apparatus for reducing the input dynamic range requirements to a signal processor, the combination comprising: means for dividing the video signal of each range sweep of said pulsed radar system into range elements; means for controlling the amplitude of said video signal in said radar system in response to an automatic gain control signal; and means including a summing circuit, a plurality of parallel operation shift registers coupled to a summing circuit and a feedback path providing a gain factor less than one and coupled between said shift registers and said summing circuit, and providing said automatic gain control signal for each range element of a given sweep as a function of a running average of the video signal amplitude of a pre-determined number of corresponding range elements from successive range sweeps.
Claim 6
Dependent Claim
147 words
In a pulsed radar system transmitting pulses during each of a plurality of range sweeps, apparatus for reducing the input dynamic range requirements to a signal processor, the combination comprising: means for dividing the video signal of each range sweep of said pulsed radar system into range elements; means for controlling the amplitude of said video signal in said radar system in response to an automatic gain control signal; and means including a summing circuit, a plurality of parallel operation shift registers coupled to a summing circuit and a feedback path providing a gain factor less than one and coupled between said shift registers and said summing circuit, and providing said automatic gain control signal for each range element of a given sweep as a function of a running average of the video signal amplitude of a pre-determined number of corresponding range elements from successive range sweeps.
Claim 7
Dependent Claim
63 words
Apparatus as defined in claim 3 wherein said feedback path is selected with said gain factor to provide said predetermined number of corresponding range elements from successive range sweeps with an effective video signal averaging period in azimuth for a given range element sufficiently long to span a selected number of said range sweeps of said radar as said radar scans in azimuth.
Claim 8
Dependent Claim
81 words
In a pulsed radar system, apparatus for generating an adaptive automatic gain control signal comprising: means for detecting the envelope of video signals from range sweeps; means for forming a running weighted average of said envelope in range; and means connected to said envelope averaging means for dividing each range sweep into a predetermined number of range elements, and for forming a weighted running average in azimuth of corresponding range element envelope averages to provide said adaptive automatic gain control signal.
Claim 9
Dependent Claim
81 words
In a pulsed radar system, apparatus for generating an adaptive automatic gain control signal comprising: means for detecting the envelope of video signals from range sweeps; means for forming a running weighted average of said envelope in range; and means connected to said envelope averaging means for dividing each range sweep into a predetermined number of range elements, and for forming a weighted running average in azimuth of corresponding range element envelope averages to provide said adaptive automatic gain control signal.
Claim 10
Dependent Claim
152 words
In a pulsed radar system, apparatus for generating an adaptive automatic gain control signal comprising: means for detecting the envelope of video signals from range sweeps; means connected to said detecting means for forming a running weighted average of said envelope; means connected to said averaging means for adding said running weighted average of said envelope to a signal at a separate terminal; means for periodically sampling the sum signal at the output of said adding means, the period of sampling being selected to divide a given range sweep into a predetermined number of range elements; means for storing the signal amplitude of each successive sample of said given range sweep; means for recirculating the successive samples of said given range sweep during an immediately following range sweep to provide said signal at said separate terminal; and means connected to said separate terminal for coupling therefrom said adaptive automatic gain control signal.
Claim 11
Dependent Claim
152 words
In a pulsed radar system, apparatus for generating an adaptive automatic gain control signal comprising: means for detecting the envelope of video signals from range sweeps; means connected to said detecting means for forming a running weighted average of said envelope; means connected to said averaging means for adding said running weighted average of said envelope to a signal at a separate terminal; means for periodically sampling the sum signal at the output of said adding means, the period of sampling being selected to divide a given range sweep into a predetermined number of range elements; means for storing the signal amplitude of each successive sample of said given range sweep; means for recirculating the successive samples of said given range sweep during an immediately following range sweep to provide said signal at said separate terminal; and means connected to said separate terminal for coupling therefrom said adaptive automatic gain control signal.
Claim 12
Dependent Claim
37 words
Apparatus as defined in claim 9 wherein said recirculating means has a gain of K less than one, whereby said adaptive automatic gain control signal is generated as a running weighted average of corresponding range sweep samples.
Claim 13
Dependent Claim
159 words
An automatic gain control system operable in a pulsed radar system providing radar return signals during each range element of a plurality of range sweeps comprising: IF amplifier means responsive to said radar signals; means for detecting the envelope of said radar signals; integrating means coupled to said means for detecting for forming a running weighted average of said envelope; summing means coupled to said integrating means; sampling means coupled to said summing means for sampling the signal during each of a plurality of range elements; shift register means coupled to said sampling means for storing the sampled signal during each range element of a sweep; gain control means coupled to said shift register means having a gain constant K less than 1; low pass filter means coupled between said gain control means and said summing means; and means coupling said low pass filter means and said IF amplifier means to control the gain of said IF amplifier means.
Claim 14
Dependent Claim
159 words
An automatic gain control system operable in a pulsed radar system providing radar return signals during each range element of a plurality of range sweeps comprising: IF amplifier means responsive to said radar signals; means for detecting the envelope of said radar signals; integrating means coupled to said means for detecting for forming a running weighted average of said envelope; summing means coupled to said integrating means; sampling means coupled to said summing means for sampling the signal during each of a plurality of range elements; shift register means coupled to said sampling means for storing the sampled signal during each range element of a sweep; gain control means coupled to said shift register means having a gain constant K less than 1; low pass filter means coupled between said gain control means and said summing means; and means coupling said low pass filter means and said IF amplifier means to control the gain of said IF amplifier means.
Claim 15
Dependent Claim
23 words
The combination of claim 8 in which said means coupling said low pass filter means includes an amplifier having a gain constant 1-K.
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) | 1976-03-05 | 1976-09-04 | 1977-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-05 | 1980-09-04 | 1981-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-05 | 1984-09-04 | 1985-03-06 | $7700.00 | Window Closed / Lapsed |