US3738731A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Varying area optical processing fourier analyzer
Assignee: General Electric Co
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Filing: 1971-08-25
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Granted: 1973-06-12
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Expires: 1991-08-25
Abstract
Abstract Signal to be analyzed for frequency content is recorded as variable-width track on film. This image is transformed by conventional coherent optics, and real frequency components appear along the real axis, extraneous components caused by variable-width record being off this axis and so readily excluded from consideration.
Inventors
- 👤 S Chandra
- 👤 R Lambert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:25
CPC Classifications
G; G06; G06E; G06E3/00; G06E3/001
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
166 words
Means for indicating the frequency spectrum of a time-varying signal comprising: a. a variable-width record of the signal in which one axis is the axis of time and the other axis is the axis of amplitude of the signal and the signal is recorded as a symmetrical band transparent and optically uniform between its amplitude boundaries and the record medium is opaque outside the boundaries; b. a source of coherent light directed axially through a convergent spherical lens; c. means for supporting the record between the lens and the source of coherent light so that the coherent light beam traverses the transparent parts of the record medium and the lens; d. mask means at the image plane of the lens comprising a sheet opaque to the said coherent light having a single slit transparent thereto parallel to and in line with the image of the time axis of the said record whereby light spots appearing in said slit represent the frequency spectrum of said timevarying signal.
Claim 2
Dependent Claim
166 words
Means for indicating the frequency spectrum of a time-varying signal comprising: a. a variable-width record of the signal in which one axis is the axis of time and the other axis is the axis of amplitude of the signal and the signal is recorded as a symmetrical band transparent and optically uniform between its amplitude boundaries and the record medium is opaque outside the boundaries; b. a source of coherent light directed axially through a convergent spherical lens; c. means for supporting the record between the lens and the source of coherent light so that the coherent light beam traverses the transparent parts of the record medium and the lens; d. mask means at the image plane of the lens comprising a sheet opaque to the said coherent light having a single slit transparent thereto parallel to and in line with the image of the time axis of the said record whereby light spots appearing in said slit represent the frequency spectrum of said timevarying signal.
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) | 1976-06-11 | 1976-12-11 | 1977-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-11 | 1980-12-11 | 1981-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-11 | 1984-12-11 | 1985-06-12 | $7700.00 | Window Closed / Lapsed |