Patent US3818894A successfully refreshed from Google Patents.
US3889166A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic frequency control for a sandwich transducer using voltage feedback
Assignee: Quintron Inc
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Filing: 1974-01-15
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Granted: 1975-06-10
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Expires: 1994-01-15
Abstract
Abstract An automatic drive control circuit for energizing or driving a sandwich transducer, which includes a mechanical displacement amplifier, piezoelectric crystal drivers and feedback piezoelectric crystals, compares the feedback voltage proportional to displacement and the driving voltage. The frequency of such driving voltage is automatically adjusted to drive the sandwich transducer at mechanical resonance, which occurs when the feedback voltage equals or exceeds the driving voltage. The drive control includes a sweep circuit coupled to a variable frequency oscillator, which produces an AC square wave signal at a frequency dependent on the sweep signal, and the AC signal is amplified and provided as the driving signal to the sandwich transducer. A comparator compares the driving voltage with the feedback voltage, and when the latter equals or exceeds the former, the sweep circuit locks at a fixed voltage to lock the oscillator AC signal frequency, which is maintained constant while the sandwich transducer is maintained at mechanical resonance.
Inventors
- 👤 Lawrence D Scurlock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:04
CPC Classifications
A; A61; A61B; A61B17/00; A61B17/16; A61B17/1613; A61B17/1628; A61B17/1657; B; B06; B06B; B06B1/00; B06B1/02; B06B1/0207; B06B1/0223; B06B1/0238; B06B1/0246; B06B1/0261; H; H03; H03L; H03L7/00; H03L7/02; H04; H04R; H04R3/00; H04R3/002; H04R3/04; B06B2201/00; B06B2201/50; B06B2201/55; B06B2201/70; B06B2201/76
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
342 words
An automatic drive circuit for driving a mechanical displacement device or the like at resonance, comprising in combination: a. variable frequency oscillator means for generating an AC signal at a frequency determined by an input signal thereto and in a range including the resonant frequency of such device; b. amplifier means responsive to such AC signal for producing a drive signal for said mechanical displacement device to effect displacement in the same; c. feedback means mounted to said device and responsive to such displacement for producing a feedback voltage proportionally representative of said displacement; comparator means for comparing the voltage of such drive signal and such feedback voltage, said comparator means producing a first sweep control output signal when said drive signal voltage exceeds such feedback voltage, and producing a second sweep control output signal when said feedback signal exceeds said drive signal; e. sweep circuit means having an input connected to the output of said comparator means and responsive to such sweep control output signal for generating a sweep signal as a periodcially varying voltage signal in response to said first sweep control output signal, when such drive signal voltage exceeds such feedback voltage, and for generating a fixed voltage output signal, when such feedback voltage equals or exceeds such drive signal voltage, said sweep circuit means having an output coupled to said variable frequency oscillator means to provide such sweep signal as such input signal to said variable frequency oscillator; whereby said voltage comparator means locks said sweep circuit means to produce a fixed voltage output signal at a magnitude to effect operation of said variable frequency oscillator means and amplifier means at a fixed frequency to provide a drive signal to the mechanical displacement device for driving the same at resonance when such feedback voltage equals or exceeds such drive signal voltage and whereby said voltage comparator unlocks said sweep circuit means to produce said periodically varying voltage signal to drive said variable frequency oscillator as a sweep frequency oscillator when said drive signal voltage exceeds said feedback voltage.
Claim 2
Dependent Claim
342 words
An automatic drive circuit for driving a mechanical displacement device or the like at resonance, comprising in combination: a. variable frequency oscillator means for generating an AC signal at a frequency determined by an input signal thereto and in a range including the resonant frequency of such device; b. amplifier means responsive to such AC signal for producing a drive signal for said mechanical displacement device to effect displacement in the same; c. feedback means mounted to said device and responsive to such displacement for producing a feedback voltage proportionally representative of said displacement; comparator means for comparing the voltage of such drive signal and such feedback voltage, said comparator means producing a first sweep control output signal when said drive signal voltage exceeds such feedback voltage, and producing a second sweep control output signal when said feedback signal exceeds said drive signal; e. sweep circuit means having an input connected to the output of said comparator means and responsive to such sweep control output signal for generating a sweep signal as a periodcially varying voltage signal in response to said first sweep control output signal, when such drive signal voltage exceeds such feedback voltage, and for generating a fixed voltage output signal, when such feedback voltage equals or exceeds such drive signal voltage, said sweep circuit means having an output coupled to said variable frequency oscillator means to provide such sweep signal as such input signal to said variable frequency oscillator; whereby said voltage comparator means locks said sweep circuit means to produce a fixed voltage output signal at a magnitude to effect operation of said variable frequency oscillator means and amplifier means at a fixed frequency to provide a drive signal to the mechanical displacement device for driving the same at resonance when such feedback voltage equals or exceeds such drive signal voltage and whereby said voltage comparator unlocks said sweep circuit means to produce said periodically varying voltage signal to drive said variable frequency oscillator as a sweep frequency oscillator when said drive signal voltage exceeds said feedback voltage.
Claim 3
Dependent Claim
246 words
An automatic drive circuit for driving a mechanical displacement device or the like at resonance, comprising in combination: variable frequency oscillator means for generating an AC signal at a frequency determined by an input signal thereto; amplifier means responsive to such AC signal for producing a drive signal for said mechanical displacement device to effect displacement in the same; feedback means responsive to such displacement for producing a feedback voltage proportionally representative thereof; comparator means for comparing the voltage of such drive signal and such feedback voltage, said comparator means producing a sweep control output signal indicative of whether such drive signal voltage exceeds such feedback voltage; sweep circuit means responsive to such sweep control output signal for generating a sweep signal as a periodically varying voltage signal, when such drive signal voltage exceeds such feedback voltage, and as a fixed voltage signal, when such feedback voltage equals or exceeds such drive signal voltage, said sweep circuit means being coupled to said variable frequency oscillator means to provide such sweep signal as such input signal thereto; whereby said voltage comparator means locks said sweep circuit means to produce such fixed voltage sweep signal at a magnitude to effect operation of said variable frequency oscillator means and amplifier means to provide a drive signal to the mechanical displacement device for driving the same at resonance when such feedback voltage equals or exceeds such drive signal voltage wherein said variable frequency oscillator means comprises a pulse shaping circuit.
Claim 4
Dependent Claim
246 words
An automatic drive circuit for driving a mechanical displacement device or the like at resonance, comprising in combination: variable frequency oscillator means for generating an AC signal at a frequency determined by an input signal thereto; amplifier means responsive to such AC signal for producing a drive signal for said mechanical displacement device to effect displacement in the same; feedback means responsive to such displacement for producing a feedback voltage proportionally representative thereof; comparator means for comparing the voltage of such drive signal and such feedback voltage, said comparator means producing a sweep control output signal indicative of whether such drive signal voltage exceeds such feedback voltage; sweep circuit means responsive to such sweep control output signal for generating a sweep signal as a periodically varying voltage signal, when such drive signal voltage exceeds such feedback voltage, and as a fixed voltage signal, when such feedback voltage equals or exceeds such drive signal voltage, said sweep circuit means being coupled to said variable frequency oscillator means to provide such sweep signal as such input signal thereto; whereby said voltage comparator means locks said sweep circuit means to produce such fixed voltage sweep signal at a magnitude to effect operation of said variable frequency oscillator means and amplifier means to provide a drive signal to the mechanical displacement device for driving the same at resonance when such feedback voltage equals or exceeds such drive signal voltage wherein said variable frequency oscillator means comprises a pulse shaping circuit.
Claim 5
Dependent Claim
37 words
An automatic drive circuit for driving a mechanical displacement device or the like at resonance as set forth in claim 2, wherein said pulse circuit comprises a plurality of NAND circuits coupled to a JK flip-flop circuit.
Claim 6
Dependent Claim
296 words
An automatic drive circuit for driving a mechanical displacement device or the like at resonance, comprising in combination: variable frequency oscillator means for generating an AC signal at a frequency determined by an input signal thereto; transistorized amplifier meAns responsive to such AC signal for producing a drive signal for said mechanical displacement device to effect displacement in the same; feedback means responsive to such displacement for producing a feedback voltage proportionally representative thereof; comparator means for comparing the voltage of such drive signal and such feedback voltage, said comparator means producing a sweep control output signal indicative of whether such drive signal voltage exceeds such feedback voltage; sweep circuit means responsive to such sweep control output signal for generating a sweep signal as a periodically varying voltage signal, when such drive signal voltage exceeds such feedback voltage, and as a fixed voltage signal, when such feedback voltage equals or exceeds such drive signal voltage, said sweep circuit means being coupled to said variable frequency oscillator means to provide such sweep signal as such input signal thereto; whereby said voltage comparator means locks said sweep circuit means to produce such fixed voltage sweep signal at a magnitude to effect operation of said variable frequency oscillator means and amplifier means to provide a drive signal to the mechanical displacement device for driving the same at resonance when such feedback voltage equals or exceeds such drive signal voltage wherein said amplifier means further comprises a coupling transformer coupled between the same and said mechanical displacement device, said coupling transformer including a center-tapped primary winding for periodic and alternate current flow in opposed directions through at least portions of the same, the secondary of said amplifier being coupled to provide such drive signal to drive the mechanical displacement device.
Claim 7
Dependent Claim
296 words
An automatic drive circuit for driving a mechanical displacement device or the like at resonance, comprising in combination: variable frequency oscillator means for generating an AC signal at a frequency determined by an input signal thereto; transistorized amplifier meAns responsive to such AC signal for producing a drive signal for said mechanical displacement device to effect displacement in the same; feedback means responsive to such displacement for producing a feedback voltage proportionally representative thereof; comparator means for comparing the voltage of such drive signal and such feedback voltage, said comparator means producing a sweep control output signal indicative of whether such drive signal voltage exceeds such feedback voltage; sweep circuit means responsive to such sweep control output signal for generating a sweep signal as a periodically varying voltage signal, when such drive signal voltage exceeds such feedback voltage, and as a fixed voltage signal, when such feedback voltage equals or exceeds such drive signal voltage, said sweep circuit means being coupled to said variable frequency oscillator means to provide such sweep signal as such input signal thereto; whereby said voltage comparator means locks said sweep circuit means to produce such fixed voltage sweep signal at a magnitude to effect operation of said variable frequency oscillator means and amplifier means to provide a drive signal to the mechanical displacement device for driving the same at resonance when such feedback voltage equals or exceeds such drive signal voltage wherein said amplifier means further comprises a coupling transformer coupled between the same and said mechanical displacement device, said coupling transformer including a center-tapped primary winding for periodic and alternate current flow in opposed directions through at least portions of the same, the secondary of said amplifier being coupled to provide such drive signal to drive the mechanical displacement device.
Claim 8
Dependent Claim
42 words
An automatic drive circuit for driving a mechanical displacement device or the like at resonance as set forth in claim 4, further comprising an adjustable voltage power supply coupled to the center-tap of said coupling transformer primary winding for providing power thereto.
Claim 9
Dependent Claim
291 words
An automatic drive circuit for driving a mechanical displacement device or the like at resonance, comprising in combination: variable frequency oscillator means for generating an AC signal at a frequency determined by an input signal thereto; amplifier means responsive to such AC signal for producing a drive signal for said mechanical displacement device to effect displacement in the same; feedback means responsive to such displacement for producing a feedback voltage proportionally representative thereof; comparator means for comparing the voltage of such drive signal and such feedback voltage, said comparator means producing a sweep control output signal indicative of whether such drive signal voltage exceeds such feedback voltage; k sweep circuit means responsive to such sweep control output signal for generating a sweep signal as a periodically varying voltage signal, when such drive signal voltage exceeds such feedback voltage, and as a fixed voltage signal, when such feedback voltage equals or exceeds such drive signal voltage, said sweep circuit means being coupled to said variable frequency oscillator means to provide such sweep signal as such input signal thereto; whereby said voltage comparator means locks said sweep circuit means to produce such fixed voltage sweep signal at a magnitude to effect operation of said variable frequency oscillator means and amplifier means to provide a drive signal to the mechanical displacement device for driving the same at resonance when such feedback voltage equals or exceeds such drive signal voltage wherein said feedback means comprises piezoelectric crystals coupled in said mechanical displacement device and wherein said comparator means comprises a coupling transformer having a primary winding connected for energization by said piezoelectric crystals in said feedback means, and a full-wave bridge rectifier coupled to the secondary winding of said coupling transformer fOr providing DC feedback.
Claim 10
Dependent Claim
291 words
An automatic drive circuit for driving a mechanical displacement device or the like at resonance, comprising in combination: variable frequency oscillator means for generating an AC signal at a frequency determined by an input signal thereto; amplifier means responsive to such AC signal for producing a drive signal for said mechanical displacement device to effect displacement in the same; feedback means responsive to such displacement for producing a feedback voltage proportionally representative thereof; comparator means for comparing the voltage of such drive signal and such feedback voltage, said comparator means producing a sweep control output signal indicative of whether such drive signal voltage exceeds such feedback voltage; k sweep circuit means responsive to such sweep control output signal for generating a sweep signal as a periodically varying voltage signal, when such drive signal voltage exceeds such feedback voltage, and as a fixed voltage signal, when such feedback voltage equals or exceeds such drive signal voltage, said sweep circuit means being coupled to said variable frequency oscillator means to provide such sweep signal as such input signal thereto; whereby said voltage comparator means locks said sweep circuit means to produce such fixed voltage sweep signal at a magnitude to effect operation of said variable frequency oscillator means and amplifier means to provide a drive signal to the mechanical displacement device for driving the same at resonance when such feedback voltage equals or exceeds such drive signal voltage wherein said feedback means comprises piezoelectric crystals coupled in said mechanical displacement device and wherein said comparator means comprises a coupling transformer having a primary winding connected for energization by said piezoelectric crystals in said feedback means, and a full-wave bridge rectifier coupled to the secondary winding of said coupling transformer fOr providing DC feedback.
Claim 11
Dependent Claim
325 words
An automatic drive circuit for driving a mechanical displacement device or the like at resonance, comprising in combination: variable frequency oscillator means for generating an AC signal at a frequency determined by an input signal thereto; amplifier means responsive to such AC signal for producing a drive signal for said mechanical displacement device to effect displacement in the same; feedback means responsive to such displacement for producing a feedback voltage proportionally representative thereof; comparator means for comparing the voltage of such drive signal and such feedback voltage, said comparator means producing a sweep control output signal indicative of whether such drive signal voltage exceeds such feedback voltage; sweep circuit means responsive to such sweep control output signal for generating a sweep signal as a periodically varying voltage signal, when such drive signal voltage exceeds such feedback voltage, and as a fixed voltage signal, when such feedback voltage equals or exceeds such drive signal voltage, said sweep circuit means being coupled to said variable frequency oscillator means to provide such sweep signal as such input signal thereto; whereby said voltage comparator means locks said sweep circuit means to produce such fixed voltage sweep signal at a magnitude to effect operation of said variable frequency oscillator means and amplifier means to provide a drive signal to the mechanical displacement device for driving the same at resonance when such feedback voltage equals or exceeds such drive signal voltage wherein said comparator means comprises first and second isolation circuits and a comparison circuit, said first isolation circuit receiving such drive signal voltage and providing a first output signal representative thereof and said second isolation circuit receiving such feedback voltage and producing a second output signal representative thereof, said comparison circuit comparing said first and second output signals and providing said sweep control output signal as a high level signal when the former exceeds the latter and as a low level signal when the latter equals or exceeds the former.
Claim 12
Dependent Claim
325 words
An automatic drive circuit for driving a mechanical displacement device or the like at resonance, comprising in combination: variable frequency oscillator means for generating an AC signal at a frequency determined by an input signal thereto; amplifier means responsive to such AC signal for producing a drive signal for said mechanical displacement device to effect displacement in the same; feedback means responsive to such displacement for producing a feedback voltage proportionally representative thereof; comparator means for comparing the voltage of such drive signal and such feedback voltage, said comparator means producing a sweep control output signal indicative of whether such drive signal voltage exceeds such feedback voltage; sweep circuit means responsive to such sweep control output signal for generating a sweep signal as a periodically varying voltage signal, when such drive signal voltage exceeds such feedback voltage, and as a fixed voltage signal, when such feedback voltage equals or exceeds such drive signal voltage, said sweep circuit means being coupled to said variable frequency oscillator means to provide such sweep signal as such input signal thereto; whereby said voltage comparator means locks said sweep circuit means to produce such fixed voltage sweep signal at a magnitude to effect operation of said variable frequency oscillator means and amplifier means to provide a drive signal to the mechanical displacement device for driving the same at resonance when such feedback voltage equals or exceeds such drive signal voltage wherein said comparator means comprises first and second isolation circuits and a comparison circuit, said first isolation circuit receiving such drive signal voltage and providing a first output signal representative thereof and said second isolation circuit receiving such feedback voltage and producing a second output signal representative thereof, said comparison circuit comparing said first and second output signals and providing said sweep control output signal as a high level signal when the former exceeds the latter and as a low level signal when the latter equals or exceeds the former.
Claim 13
Dependent Claim
305 words
An automatic drive circuit for driving a mechanical displacement device or the like at resonance, comprising in combination: variable frequency oscillator means for generating an AC signal at a frequency determined by an input signal thereto; amplifier means responsive to such AC signal for producing a drive signal for said mechanical displacement device to effect displacement in the same; feedback means responsive to such displacement for producing a feedback voltage proportionally representative thereof; comparator means for comparing the voltage of such drive signal and such feedback voltage, said comparator means producing a sweep control output signal indicative of whether such drive signal voltage exceeds such feedback voltage; sweep circuit means responsive to such sweep control output signal for generating a sweep signal as a periodically varying voltage signal, when such drive signal voltage exceeds such feedback voltage, and as a fixed voltage signal, when such feedback voltage equals or exceeds such drive signal voltage, said sweep circuit means being coupled to said variable frequency oscillator means to provide such sweep signal as such input signal thereto; whereby said voltage comparator means locks said sweep circuit means to produce such fixed voltage sweep signal at a magnitude to effect operation of said variable frequency oscillator means and amplifier means to provide a drive signal to the mechanical displacement device for driving the same at resonance when such feedback voltage equals or exceeds such drive signal voltage wherein said sweep circuit means comprises an oscillator circuit including a charging capacitor and controlled means for substantially linearly charging said charging capacitor, said controlLed means being responsive to such sweep control output signal to effect charging of said charging capacitor when such sweep control output signal indicates that such drive signal voltage exceeds such feedback voltage, and means for coupling said charging capacitor to said variable frequency oscillator means.
Claim 14
Dependent Claim
305 words
An automatic drive circuit for driving a mechanical displacement device or the like at resonance, comprising in combination: variable frequency oscillator means for generating an AC signal at a frequency determined by an input signal thereto; amplifier means responsive to such AC signal for producing a drive signal for said mechanical displacement device to effect displacement in the same; feedback means responsive to such displacement for producing a feedback voltage proportionally representative thereof; comparator means for comparing the voltage of such drive signal and such feedback voltage, said comparator means producing a sweep control output signal indicative of whether such drive signal voltage exceeds such feedback voltage; sweep circuit means responsive to such sweep control output signal for generating a sweep signal as a periodically varying voltage signal, when such drive signal voltage exceeds such feedback voltage, and as a fixed voltage signal, when such feedback voltage equals or exceeds such drive signal voltage, said sweep circuit means being coupled to said variable frequency oscillator means to provide such sweep signal as such input signal thereto; whereby said voltage comparator means locks said sweep circuit means to produce such fixed voltage sweep signal at a magnitude to effect operation of said variable frequency oscillator means and amplifier means to provide a drive signal to the mechanical displacement device for driving the same at resonance when such feedback voltage equals or exceeds such drive signal voltage wherein said sweep circuit means comprises an oscillator circuit including a charging capacitor and controlled means for substantially linearly charging said charging capacitor, said controlLed means being responsive to such sweep control output signal to effect charging of said charging capacitor when such sweep control output signal indicates that such drive signal voltage exceeds such feedback voltage, and means for coupling said charging capacitor to said variable frequency oscillator means.
Claim 15
Dependent Claim
57 words
An automatic drive circuit for driving a mechanical displacement devicr or the like at resonance as set forth in claim 8, wherein said sweep circuit means further comprises means for preventing discharging said charging capacitor in said oscillator circuit when such sweep control output signal indicates that such feedback voltage equals or exceeds such drive signal voltage.
Claim 16
Dependent Claim
57 words
An automatic drive circuit for driving a mechanical displacement device or the like at resonance as set forth in claim 9, wherein said means for coupling in said sweep circuit means comprises a high impedance amplifier for amplifying the voltage on said charging capacitor, the output from said amplifier being coupled to said variable frequency oscillator means.
Claim 17
Dependent Claim
53 words
An automatic drive circuit for driving a mechanical displacement device or the like at resonance as set forth in claim 9, wherein said sweep circuit means further comprises means for generating a minimum sweep signal to assure at least a minimum frequency for said output AC signal from said variable frequency oscillator means.
References Cited (Backward Citations)
US3434074A
Cited
US3539888A
Cited
US3586936A
Cited
US3578996A
Cited
US3716828A
Cited
US3819961A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-09 | 1978-12-09 | 1979-06-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-09 | 1982-12-09 | 1983-06-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-09 | 1986-12-09 | 1987-06-10 | $7700.00 | Window Closed / Lapsed |