Patent US6626912B2 successfully refreshed from Google Patents.
US5293137A
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Digital transducer system including two reactive transducers forming resonant oscillator circuits
Assignee: TAVIS Corp A CA CORP
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Filing: 1992-05-26
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Granted: 1994-03-08
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Expires: 2012-05-26
Abstract
Abstract A variable reluctance transducer system incorporating digital control of parallel resonant circuits including two inductive sensors L1 and L2 on each side of a flat diaphram. The dual variable reluctance elements provide dual frequency signals for digital calculation to obtain a quotient of the frequencies, thereby substantially eliminating the resonant frequencies as a variable in the accuracy of the device. Manipulation of the produced quotient by a micro-controller 10 employing digital calibration tables stored in a programmable read only memory 14 allows calibration reponsive to a temperature sensor 16, thereby substantially eliminating temperature induced errors in the system, further increasing accuracy.
Inventors
- 👤 John R. Tavis
- 👤 Laurence R. Nicholson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:29
CPC Classifications
G; G01; G01L; G01L1/00; G01L1/14; G01D; G01D18/00; G01D18/008; G01D3/00; G01D3/028; G01D3/036; G01D3/0365; G01D5/00; G01D5/12; G01D5/14; G01D5/20; G01D5/22; G01D5/2208; G01L9/00; G01L9/10; G01L9/105; H; H02; H02P; H02P25/00; H02P25/02; H02P25/032; H03; H03L; H03L5/00; H03L5/02
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
139 words
A digital transducer system receiving a force input, the system comprising: a first resonant circuit activated by a first control signal and having a first variable resonant frequency dependant on the force input; a second resonant circuit activated by a second control signal; a means for producing the first control signal and the second control signal at predetermined times; a means for frequency measurement connected to the first resonant circuit and second resonant circuit; means for calculating a quotient of the first frequency and second frequency; means for calculating a transducer value proportional to the quotient; means for calibrating the transducer value to provide a system output; and oscillator control means receiving a frequency signal from the first and second resonant circuits, when activated, for providing feedback to the first and second resonant circuits to maintain constant amplitude oscillation.
Claim 2
Dependent Claim
139 words
A digital transducer system receiving a force input, the system comprising: a first resonant circuit activated by a first control signal and having a first variable resonant frequency dependant on the force input; a second resonant circuit activated by a second control signal; a means for producing the first control signal and the second control signal at predetermined times; a means for frequency measurement connected to the first resonant circuit and second resonant circuit; means for calculating a quotient of the first frequency and second frequency; means for calculating a transducer value proportional to the quotient; means for calibrating the transducer value to provide a system output; and oscillator control means receiving a frequency signal from the first and second resonant circuits, when activated, for providing feedback to the first and second resonant circuits to maintain constant amplitude oscillation.
Claim 3
Dependent Claim
25 words
A digital transducer system as defined in Claim 1 wherein the second resonant circuit has a second variable resonant frequency dependent on the force input.
Claim 4
Dependent Claim
87 words
A digital transducer as defined in Claim 1 wherein the oscillator control means comprises: an amplifier receiving the frequency signal from the first and second resonant circuits; a detector receiving an output from the amplifier; a chopper receiving as a first input an output from the detector; a reference means for providing a voltage reference for the detector, the reference means having an output connected as a second input to the chopper; and feedback means receiving the output from the chopper and connected to the resonant circuits.
Claim 5
Dependent Claim
124 words
A digital transducer system as defined in claim 3 wherein the detector comprises a first transistor receiving as a control input the output of the amplifier and having an emitter output and wherein the reference means comprises a second transistor receiving a reference voltage at a control input and having an emitter output and wherein the chopper comprises a first diode connected to the emitter of the first transistor, a second diode connected in series to the first diode and connected with the emitter of the second transistor to a load resistor and wherein the feedback means comprises a capacitor connected at one terminal intermediate the first and second diode, the capacitor connected in series with a feedback resistor connected to the resonant circuit.
Claim 6
Dependent Claim
90 words
An oscillator controller for use in a digital transducer system having parallel resonant circuits, the controller comprising: an amplifier receiving the frequency signal from the first and second resonant circuits; a detector receiving an output from the amplifier; a chopper receiving as a first input an output from the detector; a reference means for providing a voltage reference for the detector, the reference means having an output connected as a second input to the chopper; and feedback means receiving an output from the chopper and connected to the resonant circuits.
Claim 7
Dependent Claim
90 words
An oscillator controller for use in a digital transducer system having parallel resonant circuits, the controller comprising: an amplifier receiving the frequency signal from the first and second resonant circuits; a detector receiving an output from the amplifier; a chopper receiving as a first input an output from the detector; a reference means for providing a voltage reference for the detector, the reference means having an output connected as a second input to the chopper; and feedback means receiving an output from the chopper and connected to the resonant circuits.
Claim 8
Dependent Claim
122 words
A controller as defined in claim 5 wherein the detector comprises a first transistor receiving as a control input the output of the amplifier and having an emitter output and wherein the reference means comprises a second transistor receiving a reference voltage at a control input and having an emitter output and wherein the chopper comprises a first diode connected to the emitter of the first transistor, a second diode connected in series to the first diode and connected with the emitter of the second transistor to a load resistor and wherein the feedback means comprises a capacitor connected at one terminal intermediate the first and second diode, the capacitor connected in series with a feedback resistor connected to the resonant circuit.
References Cited (Backward Citations)
US4536719A
Cited
US5079523A
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1997-03-07 | 1997-09-06 | 1998-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-03-07 | 2001-09-06 | 2002-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-03-07 | 2005-09-06 | 2006-03-08 | $7700.00 | Window Closed / Lapsed |