Patent US3921169A successfully refreshed from Google Patents.
US3921169A
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Multiple mode radiometric system with range detection capability
Assignee: SP-MICROWAVE Inc
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Filing: 1974-07-18
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Granted: 1975-11-18
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Expires: 1994-07-18
Abstract
Abstract An improved microwave radiometric system features operation selectively in passive or active modes, providing in the active mode incoherent frequency modulated continuous wave illumination of a selected target for improving the measured radiometric temperature contrast between the target and its spatial background and for increasing the distance at which such a target may be detected. Composite noise and triangular wave frequency modulation elements in a closed-loop control system yield a constant receiver beat frequency in a system in which range data is derived.
Inventors
- 👤 Robert E Lazarchik
- 👤 Robert S Roeder
- 👤 Donald R Runkle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:49
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/86; G01S13/02; G01S13/06; G01S13/08; G01S13/32; G01S13/34; G01S13/341
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
195 words
In a high frequency radiometric system having directive antenna and radiometer receiver means, voltage controlled high frequency oscillator means, isolator means for coupling a first portion of the oscillation energy from said voltage controlled high frequency oscillator means for illumination of a target by said directive antenna means, coupler means for coupling a second portion of the oscillation energy from said voltage controlled high frequency oscillator means to said radiometer receiver means for generating therein a beat frequency signal in the presence of said illuminated target, radiometer switch means for cyclically and alternately coupling said beat frequency signal or a first reference noise signal to envelope detector means, phase detector means responsive to said envelope detector means in synchronous relation with the operation of said radiometer switch means, radiometer utilization means responsive to said phase detector means, frequency discriminator means responsive to said beat frequency signal for generating a control signal upon departure of said beat frequency from a predetermined frequency value, and control circuit means responsive to said control signal by readjusting said voltage controlled high frequency oscillator means so that the departure of said beat frequency signal from said predetermined value is corrected.
Claim 2
Dependent Claim
195 words
In a high frequency radiometric system having directive antenna and radiometer receiver means, voltage controlled high frequency oscillator means, isolator means for coupling a first portion of the oscillation energy from said voltage controlled high frequency oscillator means for illumination of a target by said directive antenna means, coupler means for coupling a second portion of the oscillation energy from said voltage controlled high frequency oscillator means to said radiometer receiver means for generating therein a beat frequency signal in the presence of said illuminated target, radiometer switch means for cyclically and alternately coupling said beat frequency signal or a first reference noise signal to envelope detector means, phase detector means responsive to said envelope detector means in synchronous relation with the operation of said radiometer switch means, radiometer utilization means responsive to said phase detector means, frequency discriminator means responsive to said beat frequency signal for generating a control signal upon departure of said beat frequency from a predetermined frequency value, and control circuit means responsive to said control signal by readjusting said voltage controlled high frequency oscillator means so that the departure of said beat frequency signal from said predetermined value is corrected.
Claim 3
Dependent Claim
42 words
Apparatus as described in claim 1 wherein said frequency discriminator means comprises: limiter means responsive to the output of said radiometer switch means, discriminator circuit means responsive to said limiter means, and low pass filter means responsive to said discriminator circuit means.
Claim 4
Dependent Claim
27 words
Apparatus as described in claim 2 further including: integrator means responsive to said low pass filter means, and target range responsive means responsive to said integrator means.
Claim 5
Dependent Claim
57 words
Apparatus as described in claim 3 further including: voltage controlled sweep wave generator means additionally responsive to said integrator means, and summation circuit means for summing the output of said voltage controlled sweep wave generator means and a second reference noise signal for application to said voltage controlled oscillator means for controlling the frequency of oscillation thereof.
Claim 6
Dependent Claim
47 words
Apparatus as described in claim 3 further including voltage level detector means responsive to said low pass filter means for coupling the output of said low pass filter means to said integrator means only when said output of said low pass filter means exceeds a predetermined value.
Claim 7
Dependent Claim
17 words
Apparatus as described in claim 3 further including means for biasing the output of said integrator means.
Claim 8
Dependent Claim
19 words
Apparatus as described in claim 6 further including means for biasing the output of said low pass filter means.
Claim 9
Dependent Claim
24 words
Apparatus as described in claim 4 further including gating means connected in series relation between said discriminator means and said low pass filter means.
Claim 10
Dependent Claim
43 words
Apparatus as described in claim 8 further including peak detector threshold means responsive to said voltage controlled sweep generator means for detecting the presence of the substantially extremum values of said voltage controlled sweep wave generator output for synchronously rendering said gate non-conducting.
Claim 11
Dependent Claim
17 words
Apparatus as described in claim 9 wherein said gating means comprises sample and hold gate circuit means.
References Cited (Backward Citations)
US3212083A
Cited
US3380055A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-17 | 1979-05-19 | 1979-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-17 | 1983-05-19 | 1983-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-17 | 1987-05-19 | 1987-11-18 | $7700.00 | Window Closed / Lapsed |