US3595084A
Expired / Lapsed
US
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Digital transducer system
Assignee: Continental Can Co Inc
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Filing: 1970-02-27
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Granted: 1971-07-27
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Expires: 1990-02-27
Abstract
Abstract A digital measuring transducer system is disclosed wherein a pair of oscillators are employed in combination with a mixer to produce an output from the mixer having a pulse repetition frequency equal to the difference in pulse repetition frequencies between the two oscillators and representative of a sensed condition. At least one of the oscillators employs a resonant circuit in the feedback path and a pressure-variable capacitive sensor is connected into the resonant circuit to vary the output frequency of the associated oscillator to produce a difference in frequencies between the two oscillators and a resultant output from the mixer indicative of the pressure condition adjacent the sensor. The second oscillator may be a reference oscillator providing a predetermined reference output frequency or the second oscillator may have a pressure-variable capacitive sensor associated therewith such that the pulse or digital output from the mixer is representative of differential pressure.
Inventors
- 👤 Robert N Bailey
- 👤 James L Strom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 10:36
CPC Classifications
G; G08; G08C; G08C19/00; G08C19/16; G08C19/26; G01; G01L; G01L13/00; G01L13/02; G01L13/025; G01L9/00; G01L9/0041; G01L9/0072; G01L9/12
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
242 words
A measuring transducer system for producing a digital output directly representative of a measured condition comprising a first oscillator for producing an oscillatory output signal at a first frequency, a second oscillator for producing an oscillatory output signal at substantially said first frequency, mixer means responsive to the output of said first and second oscillators for directly producing a pulse output at a repetition rate substantially equal to the difference in frequencies between said first and second oscillators, and pressure actuable condition sensing means for altering the oscillatory output signal frequency of at least one of said oscillators from said first frequency to alter the repetition rate of said pulse output from said mixer means from zero to a repetition rate representative of the difference in output frequencies of said first oscillator and said second oscillator whereby a digital output suitable for feeding digital-signal operated apparatuses is obtained directly from the mixer means, and wherein said mixer means comprises an electron discharge device having an output means connected between an output electrode and a common electrode of said device, the output from said first oscillator being coupled between said common electrode and a point of reference potential, and the output from said second oscillator being coupled between an input electrode of said electron discharge device and one end of a series connected resistor and capacitor circuit, the other end of the last said circuit being connected to said point of reference potential.
Claim 2
Dependent Claim
242 words
A measuring transducer system for producing a digital output directly representative of a measured condition comprising a first oscillator for producing an oscillatory output signal at a first frequency, a second oscillator for producing an oscillatory output signal at substantially said first frequency, mixer means responsive to the output of said first and second oscillators for directly producing a pulse output at a repetition rate substantially equal to the difference in frequencies between said first and second oscillators, and pressure actuable condition sensing means for altering the oscillatory output signal frequency of at least one of said oscillators from said first frequency to alter the repetition rate of said pulse output from said mixer means from zero to a repetition rate representative of the difference in output frequencies of said first oscillator and said second oscillator whereby a digital output suitable for feeding digital-signal operated apparatuses is obtained directly from the mixer means, and wherein said mixer means comprises an electron discharge device having an output means connected between an output electrode and a common electrode of said device, the output from said first oscillator being coupled between said common electrode and a point of reference potential, and the output from said second oscillator being coupled between an input electrode of said electron discharge device and one end of a series connected resistor and capacitor circuit, the other end of the last said circuit being connected to said point of reference potential.
Claim 3
Dependent Claim
37 words
The system according to claim 1 including a filter means coupled to said mixer means for receiving the pulse output thereof, and output means coupled to said filter means for receiving pulses passed by said filter means.
Claim 4
Dependent Claim
14 words
The system according to claim 2 wherein said filter means comprises a pi filter.
Claim 5
Dependent Claim
38 words
The system according to claim 3 wherein said pi filter comprises a series connected capacitor connected between one end of each of two inductors, the other end of each of the inductors being connected to a common point.
Claim 6
Dependent Claim
87 words
The system according to claim 1 wherein the output of the first oscillator is coupled across a parallel connected resistor and capacitor, the parallel connected resistor and capacitor being connected between said common electrode and said point of reference potential, and the output of said second oscillator is coupled across an inductor, the last said inductor having one end thereof connected to said input electrode, the other end of the last said inductor being connected to said one end of the series connected resistor and capacitor circuit.
Claim 7
Dependent Claim
65 words
The system according to claim 1 wherein said first oscillator has a fixed frequency and said sensing means provides changes in the output frequency of said second oscillator substantially linearly with changes in said sensed condition to cause said mixer means to provide an output pulse signal the repetition rate of which varies from zero in substantially direct proportion to changes in said sensed condition.
Claim 8
Dependent Claim
52 words
The system according to claim 6 wherein said second oscillator includes frequency determining tuned circuit means, said sensing means comprising pressure variable capacitor means electrically connected into said tuned circuit means for decreasing the frequency into said second oscillator in response to increases in the capacitance of said pressure variable capacitance means.
Claim 9
Dependent Claim
111 words
The system according to claim 1 wherein said sensing means provides changes in output frequency from said first oscillator in a given direction substantially linearly with changes in said sensed condition, said system further comprising second pressure actuable condition sensing means for altering the output frequency of said second oscillator from said first frequency in a direction opposite to said given direction, said mixer means being responsive to the output frequencies of said first and second oscillators for providing a pulse output having a pulse repetition rate representative of the difference in the conditions sensed by the first-mentioned pressure actuable condition sensing means and said second pressure actuable condition sensing means.
Claim 10
Dependent Claim
59 words
The system according to claim 8 wherein said first and second oscillators include frequency determining tuned circuit means, both said condition sensing means comprising pressure variable capacitor means electrically connected into said tuned circuit means for decreasing the frequency of said first and second oscillators in response to increases in the capacitances of the associated pressure variable capacitor means.
Claim 11
Dependent Claim
55 words
The system according to claim 1 wherein said second oscillator is a reference oscillator for providing a predetermined reference output frequency, said first oscillator having a base output frequency substantially equal to said reference output frequency and variable from said base output frequency in response to variations in the condition sensed by said sensor means.
Claim 12
Dependent Claim
64 words
The system according to claim 10 wherein said first oscillator comprises at least one active element and tuned circuit means for determining the output frequency of said first oscillator, said pressure sensitive means comprising variable capacitance means electrically connected into a feedback circuit means of said first oscillator for varying the capacitance in said tuned circuit means in response to said variations in pressure.
Claim 13
Dependent Claim
36 words
The system according to claim 10 further comprising second pressure sensitive sensor means electrically connected to said second oscillator for establishing the output frequency of said second oscillator in response to a second sensed pressure condition.
Claim 14
Dependent Claim
40 words
The system according to claim 12 wherein said sensor means electrically connected to said first oscillator and said second sensor means comprise first and second pressure sensitive capacitive means, respectively, for varying the output of said first and second oscillators.
Claim 15
Dependent Claim
53 words
The system according to claim 1 wherein said pressure sensitive means is a capacitive sensor means comprises a pair of spaced capacitor plates, at least one of said plates being movable in response to variations in pressure thereon to alter spacing of said plates and to alter the capacitance of said sensor means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-07-26 | 1975-01-25 | 1975-07-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-26 | 1979-01-25 | 1979-07-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-26 | 1983-01-25 | 1983-07-27 | $7700.00 | Window Closed / Lapsed |