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US4633516A
Expired / Lapsed
US
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Instantaneous frequency measurement receiver with digital processing
Assignee: United States Department of the Air Force
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Filing: 1985-05-30
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Granted: 1986-12-30
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Expires: 2005-05-30
Abstract
Abstract The receiver comprises a 90° hybrid and analog-to-digital convertersetween the RF section and digital processing; which makes it possible to eliminate a phase correlator, four diode detectors and two differential amplifiers used in previous IFM receivers to obtain the sine and cosine signal samples at an initial time and at a delayed time.
Inventors
- 👤 James B. Y. Tsui
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:14
CPC Classifications
G; G01; G01R; G01R23/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
137 words
An instantaneous frequency measurement receiver comprising an RF section, a 90° hybrid coupled to the RF section to split the RF signal into signals on sine and cosine lines, converter means coupled to the sine and cosine lines to convert the analog signals on the sine and cosine lines into digital format, a logic unit coupled to outputs of the converter means, said logic unit having means for storing at a time t 1 the digital signals A and B, and for storing at a time (t 1 +τ) the digital signals C and D, where A=sin ωt.sub.1 B=cos ωt.sub.1 C=sin (ωt.sub.1 -ωτ) D=cos (ωt.sub.1 -ωτ), digital means in said logic unit to perform the operations E=-BC+AD F=BD+AC G=tan .sup.-1 (E/F) ω=G/τ and to provide an output for frequency in digital format as a function of ω.
Claim 2
Dependent Claim
137 words
An instantaneous frequency measurement receiver comprising an RF section, a 90° hybrid coupled to the RF section to split the RF signal into signals on sine and cosine lines, converter means coupled to the sine and cosine lines to convert the analog signals on the sine and cosine lines into digital format, a logic unit coupled to outputs of the converter means, said logic unit having means for storing at a time t 1 the digital signals A and B, and for storing at a time (t 1 +τ) the digital signals C and D, where A=sin ωt.sub.1 B=cos ωt.sub.1 C=sin (ωt.sub.1 -ωτ) D=cos (ωt.sub.1 -ωτ), digital means in said logic unit to perform the operations E=-BC+AD F=BD+AC G=tan .sup.-1 (E/F) ω=G/τ and to provide an output for frequency in digital format as a function of ω.
Claim 3
Dependent Claim
82 words
The apparatus recited in claim 1, wherein said converter means comprises two analog-to-digital converters, which are a first converter with an input from the sine line and a second converter with an input from the cosine line, and wherein said connector means includes means to sample the outputs of said 90° hybrid and digitize said samples at time t 1 to obtain the signals A and B respectively, and at time (t 1 +τ) to obtain the signals C and D respectively.
Claim 4
Dependent Claim
125 words
The apparatus recited in claim 1, wherein said converter means comprises four analog-to-digital converters, which are a first and a second converter each having an input from the sine line, and a third and a fourth converter each having an input from the cosine line, and wherein said first and third converters respectively include means to sample the signals on the sine and cosine lines of said 90° hybrid and digitize such samples at time t 1 to obtain the signals A and B respectively, and said second and fourth converters respectively include means to sample the signals on the sine and cosine lines of said 90° hybrid and digitize such samples at time (t 1 +τ) to obtain the signals C and D respectively.
References Cited (Backward Citations)
US3181156A
Cited
US3431405A
Cited
US3602812A
Cited
US3939411A
Cited
US4021804A
Cited
US4268279A
Cited
JPS55131781A
Cited
US4336541A
Cited
US4364048A
Cited
EP0058050A1
Cited
US4426648A
Cited
JPS57204464A
Cited
JPS57207869A
Cited
JPS58129368A
Cited
US4547727A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-12-29 | 1990-06-30 | 1990-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-29 | 1994-06-30 | 1994-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-29 | 1998-06-30 | 1998-12-30 | $7700.00 | Window Closed / Lapsed |