US3926056A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Conductivity, temperature and pressure measuring system
Assignee: United States Department of the Navy
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Filing: 1974-09-26
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Granted: 1975-12-16
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Expires: 1994-09-26
Abstract
Abstract A profiler for measuring ocean conductivity, temperature and depth employs A.C. excited sensors with the ratio of each output signal to the input signal being indicative of the parameter being measured. Each sensor has an interface circuit which amplifies the output signal to a level sufficient to permit its transformation to a 16-bit signal by an analog-to-digital converter having a quadrature balancing provision that cancels the signal component caused by the A.C. excitation. The digital signals in frequency shift form are sent to the surface for processing.
Inventors
- 👤 Neil L Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:50
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/66; H03M1/68; G; G01; G01C; G01C13/00; G01C13/008; G01K; G01K1/00; G01K1/02; G01K1/024; G01L; G01L9/00; G01L9/02; G01L9/04; G01L9/045; H03M1/74; H03M1/80
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
168 words
In a system for measuring the pressure within a fluid medium, the combination of a strain gage bridge adapted to sense the pressure within said fluid medium, said bridge being excited with an AC input signal of a known constant amplitude and of a kHz frequency; a high-gain, multiple-stage amplifier having one of its stages tuned to said kHz frequency and having a negative feedback circuit; means for connecting the bridge output circuit to the input circuit of said amplifier such that the negative feedback signal equals and opposes the bridge output signal whereby said bridge and amplifier operate as a self-balancing circuit, the ratio of the amplitudes of the output signal of said amplifier and the A.C. input signal energizing said bridge when said balanced condition exists being proportional to the pressure then being sensed by said strain gage bridge; and means for producing from said A.C. input signal and the output signal of said amplifier an n-bit binary signal indicative of the value of said ratio.
Claim 2
Dependent Claim
168 words
In a system for measuring the pressure within a fluid medium, the combination of a strain gage bridge adapted to sense the pressure within said fluid medium, said bridge being excited with an AC input signal of a known constant amplitude and of a kHz frequency; a high-gain, multiple-stage amplifier having one of its stages tuned to said kHz frequency and having a negative feedback circuit; means for connecting the bridge output circuit to the input circuit of said amplifier such that the negative feedback signal equals and opposes the bridge output signal whereby said bridge and amplifier operate as a self-balancing circuit, the ratio of the amplitudes of the output signal of said amplifier and the A.C. input signal energizing said bridge when said balanced condition exists being proportional to the pressure then being sensed by said strain gage bridge; and means for producing from said A.C. input signal and the output signal of said amplifier an n-bit binary signal indicative of the value of said ratio.
Claim 3
Dependent Claim
43 words
In an arrangement as defined in claim 1 wherein said means for producing said n-bit binary signal includes a successive approximatioN digital-to-analog converter which develops an analog signal of said kHz frequency whose magnitude equals that of the output signal from said amplifier.
Claim 4
Dependent Claim
70 words
In an arrangement as defined in claim 2 wherein said means for producing said n-bit binary signal further includes a comparator that compares the bridge output signal with the analog signal developed by said digital-to-analog converter and produces therefrom a D.C. error signal indicative of any inequality therebetween, said comparator in its operation comparing both the in-phase and quadrature phase components of said bridge output signal and said analog signal.
Claim 5
Dependent Claim
80 words
In an arrangement as defined in claim 3 wherein said digital-to-analog converter further includes transformer means energized by said A.C. input signal and having n secondary windings said secondary windings producing different output voltages whose magnitudes are related to the numerical values represented by said n-bit binary signal; and means for connecting selected ones of said secondary windings into a series circuit such that the summation output voltage existing across this series circuit equals the output voltage of said amplifier.
Claim 6
Dependent Claim
85 words
In an arrangement as defined in claim 4 wherein said means for connecting selected ones of said secondary windings in a series circuit includes n two position switches each of said switches in one position being effective to connect a secondary winding into said series circuit and in the other position being effective to disconnect said secondary from said series circuit; and means for sensing the positions of said switches and for generating an n-bit binary signal indicative of the individual settings of said switches.
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) | 1978-12-15 | 1979-06-16 | 1979-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-15 | 1983-06-16 | 1983-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-15 | 1987-06-16 | 1987-12-16 | $7700.00 | Window Closed / Lapsed |