US3628151A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radiometer gain control
Assignee: SP-MICROWAVE Inc
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Filing: 1970-01-08
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Granted: 1971-12-14
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Expires: 1990-01-08
Abstract
Abstract An improved microwave radiometer of the comparison type features elimination of loss of calibration due to long term gain changes through the addition of a quadrature modulation signal path in the comparison radiometer as a means of coupling a fixed gain control reference signal into the radiometer receiver. The reference signal is ultimately separated at the output of the receiver and provides a feedback signal to correct for all undesired receiver gain changes. The radiometer and gain control signals enjoy use of a common path through a portion of the radiometer receiver and perform their individual functions in a noninterfering manner.
Inventors
- 👤 Robert S Roeder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:50
CPC Classifications
G; G01; G01K; G01K11/00; G01K11/006; H; H03; H03D; H03D1/00; H03D1/02; H03D1/04; H03G; H03G3/00; H03G3/20
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
160 words
In radio receiver apparatus, the combination comprising: first generating means for providing a first cyclic signal, second generating means for providing a second cyclic signal, driver means for operating said first generator of first cyclic signals in phase quadrature with respect to said second generator of second cyclic signals, common circuit means for supplying audiofrequency output signals, said common circuit means including signal envelope detection means and amplifier means, coupling means responsive to said first and to said second cyclic signals and coupled to the input of said common circuit means, first and second phase-sensitive detectors operated by said driver and coupled to the output of said common circuit means, gain control means connected to the output of said second phasesensitive detector for supplying control signals to a controllable gain stage of said amplifier means for the purpose of ensuring a stable overall gain characteristic for said receiver, and utilization means coupled to the output of said first phasesensitive deTector.
Claim 2
Dependent Claim
160 words
In radio receiver apparatus, the combination comprising: first generating means for providing a first cyclic signal, second generating means for providing a second cyclic signal, driver means for operating said first generator of first cyclic signals in phase quadrature with respect to said second generator of second cyclic signals, common circuit means for supplying audiofrequency output signals, said common circuit means including signal envelope detection means and amplifier means, coupling means responsive to said first and to said second cyclic signals and coupled to the input of said common circuit means, first and second phase-sensitive detectors operated by said driver and coupled to the output of said common circuit means, gain control means connected to the output of said second phasesensitive detector for supplying control signals to a controllable gain stage of said amplifier means for the purpose of ensuring a stable overall gain characteristic for said receiver, and utilization means coupled to the output of said first phasesensitive deTector.
Claim 3
Dependent Claim
40 words
Apparatus as in claim 1, wherein said first generating means includes: antenna means, a first reference signal source, a first high-frequency switch, and means for coupling said antenna means and said first reference signal source to said first high-frequency switch.
Claim 4
Dependent Claim
42 words
Apparatus as in claim 1, wherein said second generating means includes: a first reference signal source, a second reference signal source, a second high-frequency switch, and means for coupling said first and said second reference signal sources to said second high-frequency switch.
Claim 5
Dependent Claim
24 words
Apparatus as in claim 1, wherein said driver means operates said first phase-sensitive detector in phase quadrature with respect to said second phase-sensitive detector.
Claim 6
Dependent Claim
16 words
Apparatus as in claim 1, wherein said coupling means comprises hollow transmission line directional coupler means.
Claim 7
Dependent Claim
42 words
Apparatus as in claim 1, wherein said driver means supplies a control signal to said first generator and to said first phase-sensitive detector, and supplies said control signal through phase shifter means to said second generator and to said second phase-sensitive detector.
Claim 8
Dependent Claim
25 words
Apparatus as in claim 1, wherein said common circuit means includes a signal mixer fed by a local oscillator for producing an intermediate frequency signal.
Claim 9
Dependent Claim
34 words
Apparatus as in claim 1, wherein said common circuit means coupled in series includes: a signal mixer, an intermediate frequency amplifier, an envelope detector for producing an audiofrequency output, and a narrow-band audio amplifier.
Claim 10
Dependent Claim
15 words
Apparatus as in claim 1, wherein said utilization means includes means for displaying radiometric information.
Claim 11
Dependent Claim
38 words
Apparatus as in claim 1, wherein said utilization means comprises: a low-pass filter, a direct current amplifier responsive to the output of said low-pass filter, and an electrical meter responsive to the output of said direct current amplifier.
Claim 12
Dependent Claim
18 words
Apparatus as in claim 1, wherein said controllable gain stage comprises a part of said narrow-band audio amplifier.
Claim 13
Dependent Claim
18 words
Apparatus as in claim 1, wherein said controllable gain stage comprises a part of said intermediate frequency amplifier.
References Cited (Backward Citations)
US3409827A
Cited
US3525037A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-13 | 1975-06-14 | 1975-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-13 | 1979-06-14 | 1979-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-13 | 1983-06-14 | 1983-12-14 | $7700.00 | Window Closed / Lapsed |