US3795448A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Doppler shift system
Assignee: National Aeronautics and Space Administration
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Filing: 1972-06-28
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Granted: 1974-03-05
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Expires: 1992-06-28
Abstract
Abstract A system for measuring velocities of radiating particles based on doppler shift is disclosed. Light from the particles is directed through a narrow band optical filter to a Fabry-Perot interferometer initially tuned to a selected center line corresponding to zero particle doppler shift. The movable mirror of the interferometer is made to sweep about the center line by the output of a modulation oscillator. The fringe pattern output is imaged onto a pin hole through which light is directed to a photomultiplier. The output of the photomultiplier is supplied to a phase sensitive detector which is supplied with the oscillator output as a reference signal and which operates in the quadrature mode. The detector''s output is gain controlled and is combined with the oscillator''s output to adjust the interferometer''s movable mirror to acquire the line center.
Inventors
- 👤 J Fletcher
- 👤 Sol Aisenberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 00:11
CPC Classifications
G; G01; G01P; G01P3/00; G01P3/36; G01P3/366; G01P5/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
110 words
A particle velocity measuring system comprising: an interferometer means including a movable element for providing a fringe pattern as a function of the wavelength of light directed thereto and the position of said element; a photomultiplier; means for directing said fringe pattern to said photomultiplier whose output is a function of the pattern directed thereto; light directing means for selectively successively directing light to said interferometer from light-radiating moving particles in a direction perpendicular to their velocity direction and from a direction other than perpendicular to their velocity direction; and means for controlling the movement of said movable element as a function of at least the output of said photomultiplier.
Claim 2
Dependent Claim
110 words
A particle velocity measuring system comprising: an interferometer means including a movable element for providing a fringe pattern as a function of the wavelength of light directed thereto and the position of said element; a photomultiplier; means for directing said fringe pattern to said photomultiplier whose output is a function of the pattern directed thereto; light directing means for selectively successively directing light to said interferometer from light-radiating moving particles in a direction perpendicular to their velocity direction and from a direction other than perpendicular to their velocity direction; and means for controlling the movement of said movable element as a function of at least the output of said photomultiplier.
Claim 3
Dependent Claim
38 words
A system as recited in claim 1 further including optical filter means disposed between said light directing means and said interferometer for selecting a particular wavelength range of light from said particles which is directed to said interferometer.
Claim 4
Dependent Claim
25 words
A system as recited in claim 1 further including modulating means including an oscillator for controlling said movable mirror to sweep about a preselected position.
Claim 5
Dependent Claim
50 words
A system as recited in claim 3 further including phase sensitive detector means responsive to the outputs of said photomultiplier and said oscillator for providing a control signal, and feedback means for combining said control signal with the output of said oscillator to control the sweep of said movable element.
Claim 6
Dependent Claim
38 words
A system as recited in claim 4 further including, optical filter means disposed between said light directing means and said interferometer for selecting a particular wavelength range of light from said particles which is directed to said interferometer.
Claim 7
Dependent Claim
54 words
A system as recited in claim 4 wherein said light density means including a first light pipe for passing light in a direction perpendicular to the velocity direction of said particles and at least a second light pipe for passing light from a direction other than perpendicular to the velocity direction of said particles.
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) | 1977-03-04 | 1977-09-03 | 1978-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-04 | 1981-09-03 | 1982-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-04 | 1985-09-03 | 1986-03-05 | $7700.00 | Window Closed / Lapsed |