Patent US3585597A successfully refreshed from Google Patents.
Patent US4577508A successfully refreshed from Google Patents.
US4577508A
Expired / Lapsed
US
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Optical vibration analyzer
Assignee: International Business Machines Corp
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Filing: 1984-10-24
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Granted: 1986-03-25
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Expires: 2004-10-24
Abstract
Abstract An optical vibration analyzer is disclosed in which a fiber optic probe collects back scattered light from a vibrating surface illuminated with non-coherent light. The probe is positioned very close to the vibrating surface such that the amount of light scattered back into the fiber optic probe varies with the instantaneous relative separation between the probe and vibrating surface. A photo-diode detects the varying average intensity of light received by the probe and generates a light intensity signal which is amplified to a usable level. The back scattered light is very small in comparison with ambient light and other non-correlated noise from which it is extracted. Accordingly, vibrations in the observed surface are excited by a sweep oscillator and the received signal is processed through a tracking filter locked to the sweep oscillator. The filtered output is monitored and varies directly with the vibration amplitude of the surface.
Inventors
- 👤 Russell Chaplin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:47
CPC Classifications
G; G01; G01H; G01H9/00; G01H9/004; G01H9/006
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
133 words
An optical analyzer including a fiber optic probe having a predetermined field of view, characterized in that said analyzer further comprises: means for illuminating with non-coherent light a limited area of a surface to be analyzed; a light intensity detection device for producing a first electrical signal directly related to the intensity of light received by said fiber optic probe; sweep oscillator means for providing an excitation signal to the surface to be analyzed; means for connecting said first electrical signal and said excitation signal to inputs of a tracking filter which operates to eliminate background interference signals from said first signal; and means for feeding the output of said tracking filter to an output monitor device, whereby the vibration amplitude of the surface to be monitored is output to an output device.
Claim 2
Dependent Claim
133 words
An optical analyzer including a fiber optic probe having a predetermined field of view, characterized in that said analyzer further comprises: means for illuminating with non-coherent light a limited area of a surface to be analyzed; a light intensity detection device for producing a first electrical signal directly related to the intensity of light received by said fiber optic probe; sweep oscillator means for providing an excitation signal to the surface to be analyzed; means for connecting said first electrical signal and said excitation signal to inputs of a tracking filter which operates to eliminate background interference signals from said first signal; and means for feeding the output of said tracking filter to an output monitor device, whereby the vibration amplitude of the surface to be monitored is output to an output device.
Claim 3
Dependent Claim
48 words
A vibration analyzer as defined in claim 1 wherein said illumination means includes an optical fiber mounted in a predetermined relationship with respect to said optical fiber probe, whereby the relationship of the illuminated area and the field of view of said optic probe may be directly controlled.
Claim 4
Dependent Claim
107 words
A vibration analyzer as defined in claim 1 and further comprisising a signal integration circuit responsive to said excitation signal for providing an electrical position signal indicative of the position of the surface to be measured relative to a start position and wherein said tracking filter is a dual tracking filter and the position signal is fed to a third input of said tracking filter, and further comprising means for feeding the first and second output of the tracking filter to first and second inputs of a transfer function analyzer the outputs of which are proportional to the phase and gain of the vibration of the surface.
Claim 5
Dependent Claim
17 words
A vibration analyzer as defined in claim 2 wherein said non-coherent light source is a gallium-arsenide diode.
Claim 6
Dependent Claim
72 words
A vibration analyzer as defined in claim 4 and further comprising a second fiber optic probe, said first fiber optic probe being mounted in a fixed relationship with respect to the vibrating surface and said second fiber optic probe being connected to a trailing cable, and further comprising means for switching said analyzer so as to receive signals either from said first or said second probe depending upon the desired vibration analysis.
Claim 7
Dependent Claim
153 words
An optical vibration analyzer, comprising: sweep oscillator means for inducing a frequency sweep of mechanical vibrations in an object to be analyzed; means responsive to said vibration inducing means for generating a reference signal corresponding to the induced mechanical vibrations; fiber optic probe means for generating a detection signal corresponding to the instantaneous position of a vibrating surface of said object, said vibrating surface being located remotely from the location at which the mechanical vibrations are being induced; tracking filter means for removing from said reference signal and from said detection signal frequency components other than the frequency at which vibrations are being induced; and transfer function analyzer means responsive to said reference signal and said detection signal for generating an output signal corresponding to the ratio of said reference signal and said detection signal; and means for graphically displaying said output signal as a function of the frequency of said sweep oscillator.
Claim 8
Dependent Claim
153 words
An optical vibration analyzer, comprising: sweep oscillator means for inducing a frequency sweep of mechanical vibrations in an object to be analyzed; means responsive to said vibration inducing means for generating a reference signal corresponding to the induced mechanical vibrations; fiber optic probe means for generating a detection signal corresponding to the instantaneous position of a vibrating surface of said object, said vibrating surface being located remotely from the location at which the mechanical vibrations are being induced; tracking filter means for removing from said reference signal and from said detection signal frequency components other than the frequency at which vibrations are being induced; and transfer function analyzer means responsive to said reference signal and said detection signal for generating an output signal corresponding to the ratio of said reference signal and said detection signal; and means for graphically displaying said output signal as a function of the frequency of said sweep oscillator.
Claim 9
Dependent Claim
60 words
An optical vibration analyzer as defined in claim 6 wherein said transfer function analyzer means has an alternative mode of operation wherein an alternative output signal is generated corresponding to the phase difference between said reference signal and said detection signal, said graphical display means displaying said alternative output signal as a function of the frequency of said sweep oscillator.
Claim 10
Dependent Claim
66 words
An optical vibration analyzer as defined in claim 6 and further comprising an audible monitoring device for receiving said detection signal during an alternative mode of operation in which said oscillator is held at a mechanical resonance frequency of said object and the position of said optical probe is varied in search of the position where there is a maximum audible signal corresponding to mechanical resonance.
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) | 1989-03-24 | 1989-09-23 | 1990-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-24 | 1993-09-23 | 1994-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-24 | 1997-09-23 | 1998-03-25 | $7700.00 | Window Closed / Lapsed |