US3725913A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microwave sensitivity time control circuit
Assignee: United States Department of the Air Force
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Filing: 1971-11-22
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Granted: 1973-04-03
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Expires: 1991-11-22
Abstract
Abstract A microwave sensitivity control (STC) circuit for use with a radar receiver is provided in which the STC control element is included as a part of a microwave mixer. STC control diodes are located aft of the microwave mixer diode. The receiver is operated with STC not applied until the target return is sufficiently large to cause the transfer function of the mixer-IF preamplifier to just begin compressing. At this time control bias is applied to the STC diodes which reduces the electric field intensity at the plane of the mixer diode by 25 db as the target returns become larger.
Inventors
- 👤 E Roehl
- 👤 G Carey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:33
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/02; G01S7/28; G01S7/285; G01S7/34
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
177 words
A microwave sensitivity time control circuit for a microwave radar receiver being fed RF siGnals representative of radar return signals comprising a fixed RF short, a microwave RF line having first and second ends, said first end being the input for said RF signals representative of said radar returns and said second end having positioned thereat said fixed RF short, first, second and third diodes being connected in sequence between said RF line and ground, said first diode being positioned at said input, said second diode at a first predetermined phase from said first diode, and said third diode positioned closely adjacent to said fixed RF short with said fixed RF short being at a second predetermined phase from said second diode, the position between said first diode and said fixed short being at a third predetermined phase, said third diode being a varactor or diode operating as a phase shifter, said second and third diode receiving first and second predetermined bias voltage waveforms, respectively, and intermediate frequency means receiving an output signal from said first diode.
Claim 2
Dependent Claim
177 words
A microwave sensitivity time control circuit for a microwave radar receiver being fed RF siGnals representative of radar return signals comprising a fixed RF short, a microwave RF line having first and second ends, said first end being the input for said RF signals representative of said radar returns and said second end having positioned thereat said fixed RF short, first, second and third diodes being connected in sequence between said RF line and ground, said first diode being positioned at said input, said second diode at a first predetermined phase from said first diode, and said third diode positioned closely adjacent to said fixed RF short with said fixed RF short being at a second predetermined phase from said second diode, the position between said first diode and said fixed short being at a third predetermined phase, said third diode being a varactor or diode operating as a phase shifter, said second and third diode receiving first and second predetermined bias voltage waveforms, respectively, and intermediate frequency means receiving an output signal from said first diode.
Claim 3
Dependent Claim
61 words
A microwave sensitivity time control circuit as described in claim 1 wherein said first predetermined phase being at 90* for low level RF signals, said third predetermined phase being at 180* for high level RF signals, and said second predetermined phase increasing from 90* to 180* during decay of said second predetermined bias voltage waveform as said third predetermined phase changes.
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) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |