US4816743A — Method and apparatus for the identification of os…

Claim 1

Independent Claim 194 words

A measuring method for identification of oscillatory properties of a piezo-electric transducer comprising the steps of: generating an electrical input signal having a variably selectable frequency; generating a reference output signal from said input signal; generating two sub-signals having a same frequency from said input signal, one of said sub-signals being independent of electro-mechanical properties of said transducer, the other of said sub-signals being dependent upon electro-mechanical properties of said transducer; generating a difference output signal from said sub-signals measuring said difference output signal relative to said reference signal; tuning said sub-signals constantly during operation to a deviation of zero; generating a rated value for said difference output signal; generating an actual value for a portion of said difference signal lying in phase or 180° out of phase with said reference output signal; tuning said sub-signals with a rated value-actual value differential control of that part of the difference output signal lying in phase or alternatively, 180° out of phase with said reference output signal; and using a remaining part of said difference output phase-shifted essentially by 90° relative to said reference output signal as a measure for a resonance characteristic of said transducer.

Claim 2

Dependent Claim 194 words

A measuring method for identification of oscillatory properties of a piezo-electric transducer comprising the steps of: generating an electrical input signal having a variably selectable frequency; generating a reference output signal from said input signal; generating two sub-signals having a same frequency from said input signal, one of said sub-signals being independent of electro-mechanical properties of said transducer, the other of said sub-signals being dependent upon electro-mechanical properties of said transducer; generating a difference output signal from said sub-signals measuring said difference output signal relative to said reference signal; tuning said sub-signals constantly during operation to a deviation of zero; generating a rated value for said difference output signal; generating an actual value for a portion of said difference signal lying in phase or 180° out of phase with said reference output signal; tuning said sub-signals with a rated value-actual value differential control of that part of the difference output signal lying in phase or alternatively, 180° out of phase with said reference output signal; and using a remaining part of said difference output phase-shifted essentially by 90° relative to said reference output signal as a measure for a resonance characteristic of said transducer.

Claim 3

Dependent Claim 85 words

A method as set forth in claim 1 further including the steps of: varying said sub-signals for tuning such that a sum of said sub-signals is constant; generating said reference output signal from one of said sub-signals; measuring an amplitude of said reference output signal; measuring an amplitude of said input signal; using a ratio of said measurements of said amplitudes to define a tuning relationship between said sub-signals; using a ratio of said measurements of said amplitudes for numerical evaluation of a test result.

Claim 4

Dependent Claim 31 words

A method as set forth in claim 1 including the step of measuring the remaining part of said difference output signal which is phase-shifted 90° relative to said reference output signal.

Claim 5

Dependent Claim 29 words

A method as set forth in claim 3, wherein measuring of said remaining part of said difference output signal is undertaken narrow-and at the frequency of said input signal.

Claim 6

Independent Claim 197 words

A method for operating a piezo-electric transducer at one of its resonant frequencies comprising the steps of: supplying said transducer with an electrical drive signal having a selectable frequency; generating a reference output signal from said drive signal; generating two sub-signals from said drive signal, said sub-signals having the same frequency, one of said sub-signals being dependent upon electromechanical properties of said transducer, the other sub-signal being independent of the electromechanical properties of said transducer; generating a difference output from said sub-signals by subjecting said sub-signals to a difference or summing function measuring said difference output signal relative to said reference output signal; generating a rated value for said difference output signal; generating an actual value for a portion of said difference signal lying in phase or 180° out of phase With said reference output signal; tuning said sub-signals during operation constantly to a deviation of zero with a ratedvalue-actual value differential control of that part of the difference output signal lying in phase or 180° out of phase with the reference output signals; identifying a remaining part of said difference output signal; and controlling the frequency of said drive signal to maximize said difference output signal.

Claim 7

Independent Claim 197 words

A method for operating a piezo-electric transducer at one of its resonant frequencies comprising the steps of: supplying said transducer with an electrical drive signal having a selectable frequency; generating a reference output signal from said drive signal; generating two sub-signals from said drive signal, said sub-signals having the same frequency, one of said sub-signals being dependent upon electromechanical properties of said transducer, the other sub-signal being independent of the electromechanical properties of said transducer; generating a difference output from said sub-signals by subjecting said sub-signals to a difference or summing function measuring said difference output signal relative to said reference output signal; generating a rated value for said difference output signal; generating an actual value for a portion of said difference signal lying in phase or 180° out of phase With said reference output signal; tuning said sub-signals during operation constantly to a deviation of zero with a ratedvalue-actual value differential control of that part of the difference output signal lying in phase or 180° out of phase with the reference output signals; identifying a remaining part of said difference output signal; and controlling the frequency of said drive signal to maximize said difference output signal.

Claim 8

Independent Claim 192 words

An apparatus for identification of oscillatory properties of a piezo-electric transducer, comprising: a signal generator which generates an electrical input signal having a variably selectable frequency; a tuning unit coupled to said signal generator which receives said input signal and which generates two sub-signals of the same frequency from said input signal, one of said sub-signals being independant of electro-mechanical properties of said transducer; the other of said sub-signals being dependent upon electro-mechanical properties of said transducer; a difference function unit coupled to said tuning unit which generates a difference output signal from said two sub-signals; a reference unit coupled to said signal generator which generates a reference output signal from said input signal; an evaluation unit coupled to said difference function unit and said reference for receiving said reference output signal and said difference output signal; and an automatic control unit coupled to said tuning unit which supplies a manipulated variable signal to said tuning unit in response to effecting a comparison of an actual value of that part of the difference output signal lying in phase or 180° out of phase with the reference output signal and a rated value.

Claim 9

Independent Claim 192 words

An apparatus for identification of oscillatory properties of a piezo-electric transducer, comprising: a signal generator which generates an electrical input signal having a variably selectable frequency; a tuning unit coupled to said signal generator which receives said input signal and which generates two sub-signals of the same frequency from said input signal, one of said sub-signals being independant of electro-mechanical properties of said transducer; the other of said sub-signals being dependent upon electro-mechanical properties of said transducer; a difference function unit coupled to said tuning unit which generates a difference output signal from said two sub-signals; a reference unit coupled to said signal generator which generates a reference output signal from said input signal; an evaluation unit coupled to said difference function unit and said reference for receiving said reference output signal and said difference output signal; and an automatic control unit coupled to said tuning unit which supplies a manipulated variable signal to said tuning unit in response to effecting a comparison of an actual value of that part of the difference output signal lying in phase or 180° out of phase with the reference output signal and a rated value.

Claim 10

Dependent Claim 30 words

An apparatus as set forth in claim 6 further includng a phase meter for supplying said actual value coupled to said difference function unit to receive said difference output signal.

Claim 11

Dependent Claim 16 words

An apparatus as set forth in claim 7, wherein said phase meter comprises a synchronous demodulator.

Claim 12

Dependent Claim 16 words

An apparatus as set forth in claim 8, wherein said control unit comprises an integral controller.

Claim 13

Dependent Claim 34 words

An apparatus as set forth in claim 9, wherein said integral controller includes means for effecting a differential response to an electrical signal and means for effecting a proportional response to an electrical signal.

Claim 14

Dependent Claim 40 words

An apparatus as set forth in claim 6, wherein said tuning unit comprises a capacitative diode coupled to the control unit as an actual tuning element, said diode having a variable capacitance which is selected by said manipulated variable signal.

Claim 15

Dependent Claim 46 words

An apparatus as set forth in claim 6, wherein said tuning unit comprises a field effect transistor coupled to the control unit as an actual tuning element, a drain to source resistance of said field effect transistor being variable and selectable by said manipulated variable signal.

Claim 16

Dependent Claim 39 words

An apparatus as set forth in claim 6, wherein said tuning unit comprises a slope amplifier coupled to the control unit as an actual tuning element, the gain of said slope amplifier being varied by said manipulated variable signal.

Claim 17

Dependent Claim 74 words

An apparatus as set forth in claim 6 wherein said tuning unit includes an actual tuning element comprising a first differential amplifier having two emitter coupled transistors coupled to said control unit and two emitter-coupled transistors, whereby said manipulated variable signal effects a division ratio of a current signal generated from said input signal into emitted currents of the two transistors of the first differential amplifier, said emitter currents corresponding to said two sub-signals.

Claim 18

Dependent Claim 31 words

An apparatus as set forth in claim 14, including a logarithmization unit for changing said manipulated variable signal, said logarithmization unit being coupled between the control unit and the tuning unit.

Claim 19

Dependent Claim 129 words

An apparatus as set forth in claim 14, including a second differential amplifier comprising two emitter coupled transistors, said second differential amplifier being coupled in parallel to said first differential amplifier within said tuning unit, said second differential amplifier effecting a current division function, whereby a constant current corresponding to a mean quiescent current of a current signal generated from said input signal is divided into two sub-currents at a ratio equal to said division in said first differential amplifier, each of said sub-currents being additively combined with one of said sub-currents of said first differential amplifier to form two resulting sub-currents, so that mean quiescent currents of said two resulting sub-currents are essentially independent of a change in the ratio of current division caused by the control unit.

Claim 20

Dependent Claim 31 words

An apparatus as set forth in claim 6 wherein the difference output signal and the reference output signal are followed by frequency band pass filters which are tuned to each other.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1992-03-27	1992-09-26	1993-03-28	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1996-03-27	1996-09-26	1997-03-28	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2000-03-27	2000-09-26	2001-03-28	$7700.00	Window Closed / Lapsed

Method and apparatus for the identification of oscillatory properties as well as for the operation of a piezo-electric tranducer

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