Piezoelectric Crystal Testing (e.g., Frequency, Resistance) Patents (Class 324/727)
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Patent number: 7132942Abstract: A method and apparatus for screening samples to determine which samples include a target material. Generally, the samples are pre-screened to determine which of the samples have a piezoelectric resonance when irradiated with an electric field, to thereby indicate the presence of the target material. The samples that have the piezoelectric resonance are then further screened by a different process to confirm the presence of the target material. For example, samples that have the piezoelectric resonance are further screened for a specific nuclear quadrupole resonance (NQR), a specific nuclear magnetic resonance (NMR) or a specific visual characteristic, to confirm the presence of the target material in the sample. The apparatus and method can be used, for example, to search luggage at ports of entry for the presence of cocaine hydrochloride or heroin hydrochloride.Type: GrantFiled: September 14, 2005Date of Patent: November 7, 2006Assignee: The United States of America as represented by the Secretary of the NavyInventors: Michael L. Buess, Allen M. Garroway, Joel B. Miller, James P. Yesinowski, Roy P. Lindquist
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Patent number: 7042228Abstract: The present invention is directed to an apparatus and method for a measurement system for the testing of transducers, and more particularly to the testing of piezoelectric transducers. The measurement system includes a transducer, a feedback amplifier coupled to the transducer and a signal processing circuit coupled to the output of the amplifier. The method of testing the transducer includes coupling the test signal to the transducer, disabling the amplifier, and measuring the response of the transducer to the test signal with the test processing circuit.Type: GrantFiled: February 9, 2004Date of Patent: May 9, 2006Assignee: Oceana Sensor Technologies, Inc.Inventors: Richard W. Lally, Donald E. Kennamer, Isaak Baber
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Patent number: 6998615Abstract: In a method of evaluating a piezoelectric field, non-destructive spectrometry of piezoelectric fields is performed in a semiconductor heterojunction using a technique different from PR spectroscopy. In the method, at first, first and second absorption spectra are measured by irradiating the sample with infrared light at first and second angles, respectively. Then, a peak position of an absorption band having incident-angle dependent intensity is specified, based on the first and second absorption spectra. Thus, the piezoelectric field strength is obtained using a relationship between the piezoelectric field and an electron energy level corresponding to the peak position.Type: GrantFiled: February 2, 2004Date of Patent: February 14, 2006Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Hideo Takeuchi, Yoshitsugu Yamamoto, Takahide Ishikawa
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Patent number: 6975123Abstract: A method and apparatus are disclosed which are operable to determine a capacitance associated with at least one piezoelectric element in an dual actuator disk drive. The capacitance information is used to adjust a driver used to drive the piezoelectric element. Capacitance is determined by supplying a predetermined current into the piezoelectric element(s) for a predetermined time period. A voltage associated with the piezoelectric element(s) is measured following the predetermined time period. The capacitance of the piezoelectric element(s) is then calculated based on the measured voltage, the current supplied, and the predetermined time period.Type: GrantFiled: December 20, 2001Date of Patent: December 13, 2005Assignee: Maxtor CorporationInventors: Keith Malang, Larry Hutsell
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Patent number: 6972553Abstract: A sensor readout circuit which provides a frequency signal output including a phase detector circuit responsive to an output signal from a sensor and an input signal to the sensor and configured to detect the phase difference between the input signal and the output signal, and a drive circuit responsive to the phase detector circuit and configured to maintain a fixed phase difference between the input signal and the output signal.Type: GrantFiled: February 14, 2002Date of Patent: December 6, 2005Assignee: The Charles Stark Draper Laboratory, Inc.Inventors: Anthony Petrovich, John R. Williams, Christopher E. Dubé
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Patent number: 6965272Abstract: A worldwide logistics network includes a processing center for receiving customer orders for crystal oscillators over communications links, processing the orders, and generating work orders that are selectively disseminated over communications links to programming centers at strategic locations around the world. Each of the programming centers carries an inventory of generic programmable crystal oscillators. Upon receipt of a work order, a programming center withdraws quantity of programmable crystal oscillators from inventory sufficient to fill the customer order, and, using automated parts handling equipment, the oscillators are successively directed to an interface position with a computer. There, the unique crystal frequency of each oscillator is read and each oscillator is uniquely programmed on the basis of its crystal frequency to generate an output frequency meeting customer specification.Type: GrantFiled: May 12, 2004Date of Patent: November 15, 2005Assignee: Fox Enterprises, Inc.Inventors: Eugene S. Trefethen, John W. Fallisgaard
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Patent number: 6937034Abstract: A sensor element formed of PZT is overlapped onto an actuator formed of electrostrictive elements, and both members are pinched between a rigid body that is not deformed. By impressing an alternating-current signal to the actuator, the sensor element is deformed in accordance with the amount of deformation thereof to use the thus generated electromotive force of the sensor element as a signal for the absolute value calculation.Type: GrantFiled: October 11, 2000Date of Patent: August 30, 2005Assignee: NGK Insulators, Ltd.Inventors: Yukihisa Takeuchi, Iwao Ohwada
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Patent number: 6890486Abstract: The present invention relates to quartz crystal microbalance sensors using molecular imprinting polymerization technology, providing for continuous on-line monitoring of water-borne organic contaminants.Type: GrantFiled: July 26, 2001Date of Patent: May 10, 2005Assignee: University of MassachusettsInventor: Jacques Penelle
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Patent number: 6880213Abstract: A method for quickly screening piezoelectric transformer apparatuses having low mechanical strength and latent defects is performed by connecting a load impedance to a generator of a piezoelectric transformer apparatus and applying a stress signal to an actuator to vibrate the piezoelectric transformer apparatus. Latent-defect transformer apparatuses having low mechanical strength are damaged during this process and therefore can be easily identified.Type: GrantFiled: October 19, 1999Date of Patent: April 19, 2005Assignee: Murata Manufacturing Co., LTDInventor: Takaaki Asada
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Patent number: 6870377Abstract: Method and apparatus for detecting failure in a piezoelectric element on a head suspension for a disk drive by clamping one end of the suspension, mechanically displacing and rapidly releasing the other end of the suspension, monitoring the electrical output of a piezoelectric element on the suspension and comparing the output with a predetermined output, using a clamp, motion actuator, and signal processor. The comparison may be with a predetermined voltage, and the output may be a natural frequency having a fundamental frequency corresponding to individual failure modes including adhesive fracture, piezoelectric element fracture, poling failure or a broken electrical connection.Type: GrantFiled: August 26, 2003Date of Patent: March 22, 2005Assignee: Hutchinson Technology IncorporatedInventor: Jeffrey E. Thomsen
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Patent number: 6861854Abstract: A test device and method for testing one of a disk drive microactuator and a disk drive sensor that includes two piezoelectric elements. The test device includes a signal generator, signal analyzer, and a user interface. The test device is operational to provide a reference signal (e.g. an electrical signal) to one of the piezoelectric elements in the microactuator and obtain a test measure from the other one of the piezoelectric elements. The test measure is then utilized to assess a performance parameter for the microactuator. The test measure is generated by the other one of the piezoelectric elements in response to the reference signal provided to the first one of the piezoelectric elements.Type: GrantFiled: October 11, 2002Date of Patent: March 1, 2005Assignee: Maxtor CorporationInventors: Wei Guo, Michael R. Hatch
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Publication number: 20040155194Abstract: In a method of evaluating a piezoelectric field, a non-destructive spectrometry of piezoelectric fields is performed in a semiconductor heterojunction using a technique different from PR spectroscopy. In the method, at first, first and second absorption spectra are measured by irradiating infrared light to a sample with first and second angles, respectively. Then, a peak position of an absorption band having incident-angle dependent intensity is specified based on the first and second absorption spectra. Thus, the piezoelectric field strength is obtained based on an equation of energy level. The equation represents a relationship between the piezoelectric field and an electron energy level corresponding to the peak position.Type: ApplicationFiled: February 2, 2004Publication date: August 12, 2004Applicant: Mitsubishi Denki Kabushiki KaishaInventors: Hideo Takeuchi, Yoshitsugu Yamamoto, Takahide Ishikawa
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Patent number: 6771083Abstract: A new class of highly sensitive piezoconductive strain sensor elements and sensors has been invented. The new elements function under conditions such that electrical conductivity is dominated by Poole-Frenkel transport. A substantial piezoconductive effect appears in this regime, allowing the new sensors to exhibit sensitivity to applied strain as much as two orders of magnitude in excess of prior art sensors based on doped silicon.Type: GrantFiled: March 19, 2002Date of Patent: August 3, 2004Assignee: Sandia CorporationInventor: Scott D. Habermehl
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Publication number: 20040080327Abstract: A measurement circuit and a corresponding method for a three poles monolithic quartz crystal filter. With the first and the second switch connected respectively to the first and the third pole, any terminal electrode of the filter (the second not included) is not only electrically coupled with the impedance matching circuits, but also electrically coupled with the terminal impeders or the measuring instruments according to the status of the switches. Therefore, by controlling the switches, Fo and BW of the filter could be acquired by the measuring instruments. Moreover, applying the conventional two-pole short-circuits bandwidth theorem, A-sym of the filter could also be acquired by separating the 3-poles filter into two 2-poles filter.Type: ApplicationFiled: October 25, 2002Publication date: April 29, 2004Inventor: Eric Wu
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Patent number: 6691387Abstract: A method of manufacturing a two-dimensional ultrasound transducer array is provided in which the transducer array is formed by a plurality of transducer elements sequentially arranged in the azimuth direction and each transducer element has a non-uniform thickness and each transducer is divided into a left and a right half which can be independently excited.Type: GrantFiled: April 8, 2002Date of Patent: February 17, 2004Assignee: Acuson CoporationInventor: Amin M. Hanafy
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Patent number: 6680620Abstract: A method for timed measurement of a voltage across a device in a charging circuit of a piezoelectric element. The voltage across the device is sensed and read at a predefined time in synchronization with an injection event of the at least one piezoelectric actuator. The device may be the piezoelectric element or a buffer capacitor.Type: GrantFiled: April 2, 2001Date of Patent: January 20, 2004Assignee: Robert Bosch GmbHInventors: Andreas Hedenetz, Kai Barnickel, Josef Newald, Udo Schulz
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Publication number: 20030112023Abstract: The invention relates to a mechanical-electrical transducer having a bridge circuit formed on an insulation layer through an electrical interconnection of expansion-sensitive thick-film resistors by means of conductor tracks. The insulation layer is arranged directly on a metallic component that is to be mechanically loaded, and being intimately connected to said component by means of a thermal process. In this case, in the event of mechanical stressing of the component, an electrical signal corresponding to the expansion of the thick-film resistors can be tapped off. In order that the mechanical-electrical transducer exhibits a small electrical offset in the output signal in the event of mechanical loading, the metallic component to be loaded comprises a thermally post-hardening metal or a thermally post-hardening metal alloy.Type: ApplicationFiled: November 14, 2002Publication date: June 19, 2003Inventors: Heiko Jausel, Erich Mattmann, Uwe Neumann-Henneberg
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Patent number: 6556028Abstract: Roughly described, piezoelectric actuators are tested as part of an assembly using a three-stage process. In the first stage, a substantially steady state electromechanical potential is induced into a piezoelectric member of an assembly. Typically this can be accomplished by applying a DC voltage across the crystal for long enough period of time for it to achieve a substantially steady state mechanical distortion. In the second stage, the electromechanical potential of the piezoelectric actuator is discharged rapidly but incompletely. The third stage begins with the abrupt termination of the rapid-discharge stage, thereby causing the crystal, and the voltage produced across it, to oscillate and decay freely. The voltage across the crystal continues to decay slowly in the third stage, and the oscillations continue to decay in magnitude as well, providing a relatively complex signal from which features can be extracted and compared to those of known-good devices.Type: GrantFiled: May 7, 2001Date of Patent: April 29, 2003Assignee: Storage Test Solutions, Inc.Inventors: Yuriy Umanskiy, Arnold Shpilberg, Vladimir Vaninskiy, Eugene Dvoskin
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Publication number: 20030076121Abstract: A test device and method for testing one of a disk drive microactuator and a disk drive sensor that includes two piezoelectric elements. The test device includes a signal generator, signal analyzer, and a user interface. The test device is operational to provide a reference signal (e.g. an electrical signal) to one of the piezoelectric elements in the microactuator and obtain a test measure from the other one of the piezoelectric elements. The test measure is then utilized to assess a performance parameter for the microactuator. The test measure is generated by the other one of the piezoelectric elements in response to the reference signal provided to the first one of the piezoelectric elements.Type: ApplicationFiled: August 13, 2002Publication date: April 24, 2003Inventors: Wei Guo, Michael R. Hatch
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Publication number: 20030062912Abstract: In a polarization method of the multi-layered piezoelectric body in which a plurality of piezoelectric layers and a plurality of internal electrodes are alternately laminated and adjacent piezoelectric layers are polarized in the thickness direction such that the polarized directions thereof are in opposite directions, a first polarization process in which an electric field in one direction is applied in the thickness direction to the multi-layered piezoelectric body and a polarization is uniformly performed in the thickness direction, and a secondary polarization process in which an electric field in the opposite direction is applied to the piezoelectric layers on both sides of one of the internal electrodes and the direction of polarization of only one of the piezoelectric layers on one side of the internal electrode is reversed are provided.Type: ApplicationFiled: November 30, 2001Publication date: April 3, 2003Applicant: Murata Manufacturing Co., Ltd.Inventor: Mikio Nakajima
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Patent number: 6531884Abstract: A diagnostic device for testing a piezoelectric sensor includes an AC source configured to apply an AC signal to the piezoelectric sensor at two or more different frequencies. The response of the piezoelectric sensor can be measured and used for diagnostics.Type: GrantFiled: August 27, 2001Date of Patent: March 11, 2003Assignee: Rosemount Inc.Inventor: Lowell A. Kleven
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Publication number: 20030038644Abstract: A diagnostic device for testing a piezoelectric sensor includes an AC source configured to apply an AC signal to the piezoelectric sensor at two or more different frequencies. The response of the piezoelectric sensor can be measured and used for diagnostics.Type: ApplicationFiled: August 27, 2001Publication date: February 27, 2003Inventor: Lowell A. Kleven
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Patent number: 6521166Abstract: A DC voltage is applied to a piezoelectric body for polarization treatment in the air and in an atmosphere with a temperature equal to or higher than an aging temperature, and then, the piezoelectric body is aged at the aging temperature. The polarization degree is determined based on the frequency characteristic while the piezoelectric body is polarized. The application of the DC voltage is stopped at the time when the measured polarization degree reaches a set level. The set level is determined based on a correlation between the polarization degree obtained immediately before the application of the DC voltage is stopped and the stable polarization degree obtained after the aging and the ordinary temperature restoration following the stop of the voltage application.Type: GrantFiled: August 11, 2000Date of Patent: February 18, 2003Assignee: Murata Manufacturing Co., Ltd.Inventors: Hiroshi Tomohiro, Naoki Fujii
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Patent number: 6518778Abstract: Methods are included for determining deviations from &phgr;=0° in test resonators based on the quasi-pure modes' displacement ratio variations with &phgr; angle. A direct relationship between deviation from &phgr;=0° and the c-mode displacement ratio has been observed, so that the larger the deviation from &phgr;=0°, then the larger is the change in the normalized frequency of the c-mode upon immersion in, or contact with, a fluid. The method includes measuring &thgr; and &phgr; angles in reference resonators with different small &phgr; angles and quasi-pure mode frequencies of reference resonators in both air and a test fluid at ambient temperatures, calculating the normalized frequency changes between the air and fluid measurements as a reference point, measuring the test resonator in air then in the fluid and comparing the results.Type: GrantFiled: January 23, 2001Date of Patent: February 11, 2003Assignee: The United States of America as represented by the Secretary of the ArmyInventors: John R. Vig, Arthur Ballato
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Publication number: 20030011389Abstract: A method for measuring the mass of nano-substances including the steps of gripping a nano-substance with a nanotweezer gripping portion made of a plurality of nanotubes, resonating the nanotweezer gripping portion in this gripping state, measuring a resulting first characteristic frequency, and obtaining the mass of the gripped nano-substance by comparing the first and second characteristic frequencies, where the second characteristic frequency is the characteristic frequency of the nanotweezer gripping portion with no nano-substance gripped thereby. The gripping portion is caused to resonate electrically by applying an AC voltage between the nanotweezer gripping portion and an electrode disposed near the nanotweezer gripping portion. The gripping portion is caused also to resonate mechanically by way of expanding and contracting a piezo-electric element disposed on a main body that supports the nanotweezer gripping portion.Type: ApplicationFiled: May 24, 2002Publication date: January 16, 2003Applicant: YOSHIKAZU NAKAYAMAInventors: Yoshikazu Nakayama, Akio Harada
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Patent number: 6507202Abstract: A sensed-pressure-data converter having a circuit for reducing a fluctuation of the output due to a fluctuation of a resistance and a resistance changing characteristic of a pressure sensitive resistance element and for reducing the output offset and offset drift of the pressure sensitive resistance element. The converter of the invention comprises a pressure sensitive resistance element (1), and a controller (2). The controller is an electric circuit connected to the pressure sensitive resistance element for detecting the electric characteristic of the element and includes A/D converters (3, 4), a D/A converter (6), and a memory (5). The controller compensates the electric characteristic due to a resistance change of the pressure sensitive resistance element and issues it from the D/A converter (6).Type: GrantFiled: April 3, 2001Date of Patent: January 14, 2003Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Kiyotaka Sasanouchi, Susumu Nishimoto, Norimitsu Kurihara
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Patent number: 6498501Abstract: A measuring circuit includes a symmetric transmission line connecting a transducer to a measurement amplifier and to a fault indicating signal amplifier, the transducer delivering symmetric input signals to amplifiers, the first amplifier delivering a measuring signal representing the difference of its input signals and the fault indicating signal amplifier delivering a fault indicating signal representing the sum of the input signals. An auxiliary signal injected to the terminals of the transducer the invention enables the measuring circuit to evaluate the quality of the measuring circuit during operation of the tested machine and also when the machine is at rest.Type: GrantFiled: October 18, 1999Date of Patent: December 24, 2002Assignee: Vibro-Meter, S.A.Inventor: Bernard Broillet
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Patent number: 6480073Abstract: A method of evaluating quality of a crystal unit, capable of performing quantitative measurement of an actual operation of a crystal unit which is to be oscillated in an actual oscillator to ensure an accurate quality evaluation, is provided. The method includes increasing a DC input voltage of a crystal oscillator, the crystal oscillator having at least one AGC amplifier whose amplification rate varies depending on the DC input voltage and having a crystal unit connected thereto, measuring a maximum value of the DC input voltage at a start of oscillation of the crystal oscillator, and evaluating quality of the crystal unit by the measured maximum value.Type: GrantFiled: January 19, 2001Date of Patent: November 12, 2002Assignee: Suwadenshi Co., Ltd.Inventor: Hajime Ushiyama
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Patent number: 6480010Abstract: A piezoelectric ceramic device is heated so that the temperature is increased to a temperature in the vicinity of the maximum temperature at which the device, when the temperature is returned to ordinary temperature, is returned to substantially the same piezoelectric characteristic before heating. In the state that the piezoelectric ceramic device is heated, and the temperature is increased, at least one of the piezoelectric phase characteristic and the impedance characteristic of the piezoelectric ceramic device is measured. The measurement is compared with a standard characteristic, whereby an internal defect of the piezoelectric ceramic device is detected, based on results of the comparison.Type: GrantFiled: December 22, 2000Date of Patent: November 12, 2002Assignee: Murata Manufacturing Co., Ltd.Inventors: Masato Ikuta, Toshinari Tabata, Masao Nishimura
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Publication number: 20020130673Abstract: The invention provides sensors that comprise a transducer that converts between mechanical energy and electrical energy. The transducer comprises an electroactive polymer in electrical communication with at least two electrodes. When a relatively small voltage difference is applied between the electrodes, deflection of the polymer results in a measurable change in electrical energy for the transducer. The change in electrical energy may correspond to a change in resistance, capacitance, or a combination thereof. Sensing electronics circuits in electrical communication with electrodes detect the electrical energy change.Type: ApplicationFiled: December 6, 2001Publication date: September 19, 2002Applicant: SRI InternationalInventors: Ronald E. Pelrine, Roy D. Kornbluh, Qibing Pei, Joseph Stephen Eckerle
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Publication number: 20020101253Abstract: A vibration control system comprising an actuator, and a sensor useful for controlling vibrations in systems for fabricating electronics equipment. The actuator may comprise one or more plates or elements of electroactive material bonded to an electroded sheet.Type: ApplicationFiled: March 9, 2001Publication date: August 1, 2002Inventors: Baruch Pletner, Richard Perkins, Leonard Lublin
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Patent number: 6411208Abstract: A method and apparatus for screening samples to determine which samples include a target material. Generally, the samples are pre-screened to determine which of the samples have a piezoelectric resonance when irradiated with an electric field, to thereby indicate the presence of the target material. The samples that have the piezoelectric resonance are then further screened by a different process to confirm the presence of the target material. For example, samples that have the piezoelectric resonance are further screened for a specific nuclear quadrupole resonance (NQR), a specific nuclear magnetic resonance (NMR) or a specific visual characteristic, to confirm the presence of the target material in the sample. The apparatus and method can be used, for example, to search luggage at ports of entry for the presence of cocaine hydrochloride or heroin hydrochloride.Type: GrantFiled: June 5, 1997Date of Patent: June 25, 2002Assignee: The United States of America as represented by the Secretary of the NavyInventors: Michael L. Buess, Allen N. Garroway, Joel B. Miller, James P. Yesinowski, Roy P. Lindquist
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Publication number: 20020024346Abstract: A piezoelectric ceramic device is heated so that the temperature is increased to a temperature in the vicinity of the maximum temperature at which the device, when the temperature is returned to ordinary temperature, is returned to substantially the same piezoelectric characteristic before heating. In the state that the piezoelectric ceramic device is heated, and the temperature is increased, at least one of the piezoelectric phase characteristic and the impedance characteristic of the piezoelectric ceramic device is measured. The measurement is compared with a standard characteristic, whereby an internal defect of the piezoelectric ceramic device is detected, based on results of the comparison.Type: ApplicationFiled: December 22, 2000Publication date: February 28, 2002Applicant: Murata Manufacturing Co., Ltd.Inventors: Masato Ikuta, Toshinari Tabata, Masao Nishimura
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Patent number: 6348795Abstract: A method for determining a resonant frequency of a mechanical device having a first mass and at least one second mass mechanically coupled to the first mass comprises the steps of: providing a control signal to a voltage-controlled oscillator (VCO) to control the frequency of an output thereof; translating a phase shifted output of the VCO into an oscillatory force which is applied to one of the first and second masses to cause the mechanical device to respond; measuring the response of the mechanical device and generating a response signal representative thereof in frequency and amplitude; generating an error signal proportional to the phase difference between a signal representative of the output of the VCO and the measured response signal; adjusting the control signal to cause the oscillatory force applied to the one mass to sweep within a calculated frequency range rendering the amplitude of the response signal to approach and exceed a calculated threshold value; and when the calculated threshold is exceeType: GrantFiled: July 12, 2001Date of Patent: February 19, 2002Assignee: The B. F. Goodrich Co.Inventors: Ralph Pringle, Jr., Felix E. Morgan
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Publication number: 20020008527Abstract: A measuring circuit comprising a symmetric transmission line connecting a transducer to a measurement amplifier and to a fault indicating signal amplifier, the transducer delivering symmetric input signals to said amplifiers, the first amplifier delivering a measuring signal representing the difference of its input signals and the fault indicating signal amplifier delivering a fault indicating signal representing the sum of the input signals. An auxiliary signal injected to the terminals of the transducer the invention enables the measuring circuit to evaluate the quality of the measuring circuit during operation of the tested machine and also when the machine is at rest.Type: ApplicationFiled: October 18, 1999Publication date: January 24, 2002Inventor: BERNARD BROILLET
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Publication number: 20010045837Abstract: A method and apparatus for measuring the frequency of a desired resonant mode of a crystal arrangement, or other two-port device, during an automated operation. The crystal arrangement, or other two-port device, is placed into a test circuit and subjected to a sinusoidal test signal of known frequency. Based upon the output response of the crystal arrangement to the test signal, the frequency of the test signal is changed such that the test signal rapidly converges on a desired mode of operation of the crystal arrangement. This is accomplished by first noting a desired increase in amplitude of the output response of the crystal arrangement, followed by measuring an error signal related to the desired crystal arrangement mode of operation. When the error equals a predetermined value the frequency of the sinusoidal test signal is the frequency of the desired mode.Type: ApplicationFiled: July 12, 2001Publication date: November 29, 2001Inventors: Ralph Pringle, Felix E. Morgan
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Patent number: 6321588Abstract: A device for detecting chemical substances includes a plurality of sensors arranged in an array. The sensors are connected to respective oscillator circuits which drive the sensors, and the oscillator circuits are coupled to a power multiplexer which provides the circuits with power according to a timing pattern such that not all of the oscillator circuits are activated at any one time. Preferably, only one oscillator circuit is activated at any given time. This multiplexing arrangement saves power and substantially eliminates cross talk between the oscillator circuits. The oscillator circuits are preferably application specific integrated circuits (ASICs), and the sensors are preferably surface acoustic wave (SAW) devices. In use, the SAW sensors are exposed to a gas, such as air, containing the chemical substance to be detected. Signals from the SAW sensors are analyzed to identify the chemical substance.Type: GrantFiled: September 11, 1998Date of Patent: November 27, 2001Assignee: Femtometrics, Inc.Inventors: William D. Bowers, Frank Bahrami, John Tran
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Patent number: 6320471Abstract: An electrical circuit having an oscillator and additional structural elements that are connected to the oscillator. In an iterative method, upon variation of circuit parameters of the additional structural elements, the following steps are carried out for each instance of the circuit parameters: a stability analysis of the circuit is carried out for each respective instance, and if the circuit oscillates, a first value is assigned to the instance in a matrix in which all the instances being examined are stored. Otherwise, a second value is assigned to the instance in the matrix.Type: GrantFiled: May 25, 2000Date of Patent: November 20, 2001Assignee: Siemens AktiengesellschaftInventors: Jürgen Peter, Rolf Neubert
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Patent number: 6292002Abstract: A method and apparatus for measuring the frequency of a desired resonant mode of a crystal arrangement, or other two-port device, during an automated operation. The crystal arrangement, or other two-port device, is placed into a test circuit and subjected to a sinusoidal test signal of known frequency. Based upon the output response of the crystal arrangement to the test signal, the frequency of the test signal is changed such that the test signal rapidly converges on a desired mode of operation of the crystal arrangement. This is accomplished by first noting a desired increase in amplitude of the output response of the crystal arrangement, followed by measuring an error signal related to the desired crystal arrangement mode of operation. When the error equals a predetermined value the frequency of the sinusoidal test signal is the frequency of the desired mode.Type: GrantFiled: August 16, 1999Date of Patent: September 18, 2001Assignee: The B. F. Goodrich CompanyInventors: Ralph Pringle, Jr., Felix E. Morgan
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Publication number: 20010020874Abstract: A method of evaluating quality of a crystal unit, capable of performing quantitative measurement of an actual operation of a crystal unit which is to be oscillated in an actual oscillator to ensure an accurate quality evaluation, is provided which comprises the steps of increasing a DC input voltage of a crystal oscillator, said crystal oscillator having at least one AGC amplifier whose amplification rate varies depending on the DC input voltage and having a crystal unit connected thereto; measuring a maximum value of the DC input voltage at a start of oscillation of the crystal oscillator; and evaluating quality of the crystal unit by the measured maximum value.Type: ApplicationFiled: January 19, 2001Publication date: September 13, 2001Inventor: Hajime Ushiyama
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Patent number: 6236276Abstract: In a method for seeking and setting a resonant frequency for a load impedance and a tuner for carrying out the method, a first frequency sweep is performed over a predetermined frequency interval in order to identify the resonant frequency within the predetermined frequency interval. To maintain the correct resonant frequency, regardless of signal drift and other interference, repeated sweeps are automatically performed within the predetermined frequency interval to identify the resonant frequency repeatedly. Alternating semi-sweeps can be performed to reduce the sweep duration.Type: GrantFiled: December 21, 1999Date of Patent: May 22, 2001Assignee: Siemens-Elema ABInventor: Göran Cewers
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Patent number: 6208153Abstract: Method and apparatus are described for speeding parameter measurements of piezoelectric-resonators. A large driving voltage is applied to the resonator until the resonator current reaches its desired steady-state value. Then the driving voltage is reduced to a level which will maintain that desired current level. This procedure allows the resonator to reach its steady state conditions faster than if a constant drive voltage were used.Type: GrantFiled: August 11, 1999Date of Patent: March 27, 2001Assignee: Transat CorporationInventor: David Flugan
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Patent number: 6154037Abstract: The present invention entails a circuit and method for determining the distortion created by a transformer used in data communications. The circuit according to the present invention comprises a transmitting circuit, a back matching circuit, and a subtracting circuit. The transmitting circuit generates a test signal to be transmitted into a transformer, the transmitting circuit having a transmitting output for coupling to a transformer. Once applied to the transformer, the test signal is distorted by the transformer, where the transformer creates harmonics of the test signal and other signal distortion. The back matching circuit generates a scaled test signal that is subtracted from the distorted test signal in the subtraction circuit. The result is a diminished peak at the test signal in comparison to the harmonics such that the distortion by the transformer can be determined using a measuring device with a relatively low dynamic range.Type: GrantFiled: October 13, 1998Date of Patent: November 28, 2000Assignee: Globespan Semiconductor, Inc.Inventors: Francis R. Ashley, Arnold Muralt
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Patent number: 6107791Abstract: This invention relates to an electric field sensor for near field measurement. The electric field sensor of the present invention uses both piezoelectric and converse piezoelectric resonances. Composed of no metallic parts, the probe of the sensor minimizes field disturbance. The most distinguished feature of this probe is that a signal is transmitted outside neither electrically nor optically, but mechanically.Type: GrantFiled: June 30, 1998Date of Patent: August 22, 2000Assignee: Korea Advanced Institute of Science and TechnologyInventor: Soon Chil Lee
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Patent number: 5959505Abstract: A crystal oscillator for measuring crystal impedance (CI) easily and accurately of various crystal units having an oscillating frequency in a wide band and various CI-values in a broad rage. A DC input voltage is measured, representing CI of a crystal unit, in a crystal oscillator, wherein an integrating circuit is provided in an output section providing a frequency oscillated from the crystal unit as an output, and one or more AGC amplifiers having an amplification rate proportional to a DC input voltage is provided between the crystal unit and the integrating circuit.Type: GrantFiled: December 29, 1997Date of Patent: September 28, 1999Assignee: Suwadenshi Co., Ltd.Inventor: Hajime Ushiyama
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Patent number: 5777550Abstract: A high reliability instrument system includes means for applying a test condition to the instrument and for determining whether the instrument properly responds to the test condition, and means for inhibiting the generation of an instrument output in response to such testing. This provides verification that most of the instrument system components, but not the system output, are properly functioning. The system further includes means for overriding the output-inhibiting function when it is desired to test the entire instrument system including the system output. The instrument system may include a gap-type ultrasonic instrument, with the test condition comprising a pulse applied to one crystal, the effects of which are detected at the other crystal to determine sensor integrity. The system is preferably configured as a two-wire on-off instrument system, in which application of the test condition at a transmitter is controlled by signals applied to the two-wire signal loop at a remote receiver.Type: GrantFiled: January 3, 1997Date of Patent: July 7, 1998Assignee: Drexelbrook Controls, Inc.Inventors: Frederick L. Maltby, Glen L. Mitchell, Mort Gorowitz
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Patent number: 5767682Abstract: In an electric conductivity measurement circuit according to the invention, there are provided first and second cores for forming a closed flux loop in a liquid whose electric conductivity is to be measured, a first coil is wound on the first core, and a second coil is wound on the second core in a direction opposite to the direction of the winding of the first coil, a closed circuit includes the first and second coils, a reference resistor Rr and switch means, and the switch means is periodically turned on and off to periodically incorporate the reference resistor Rr in the closed circuit, thereby calculating the electric conductivity of the liquid by comparing a voltage induced at the second coil where the reference resistor Rr is incorporated in the closed circuit, with a voltage induced at the second coil where the reference resistor Rr is not incorporated in the closed circuit.Type: GrantFiled: October 20, 1995Date of Patent: June 16, 1998Assignee: The Tsurumi-Seiki Co., Ltd.Inventors: Michio Sekimoto, Satoshi Suyama
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Patent number: 5764068Abstract: A method using quartz resonators probes dynamically the mechanical characteristics of thin films. This method probes the film properties at the anti-resonance frequency where the vibrational amplitude is smallest, minimizing nonlinear contributions in the dependence of the film mechanical characteristics on the resonator electrical characteristics. Determination of the mechanical characteristics involves impedance analysis, transformation of .vertline.Y.vertline. and .theta. data into a linear form so that the conductance and susceptance at the frequency of minimum absolute admittance can be accurately determined, and use of a two-dimensional Newton-Raphson numerical method to determine the values of the storage modulus G', loss modulus G", as well as various other film and resonator properties.Type: GrantFiled: July 25, 1996Date of Patent: June 9, 1998Assignee: California Insitute of TechnologyInventors: Alexander Katz, Michael D. Ward
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Patent number: 5646541Abstract: A circuit network measuring apparatus applies a measurement signal from a signal source to a device under test and measures circuit parameters of the device under test from the measurement signal and an output signal of the device under test. The apparatus includes a function which adds a frequency follow-up algorithm to a computer control portion to vary the output frequency of the signal source, thereby performing control such that the measured value will substantially equal a given value.Type: GrantFiled: March 22, 1995Date of Patent: July 8, 1997Assignee: Hewlett-Packard CompanyInventor: Kazuhiko Ninomiya
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Patent number: 5594354Abstract: The present invention discloses a method for obtaining frequency parameters to determine the resonator frequencies, the synchronous peak separation frequency, and the normal center frequency of a coupled-dual resonator crystal. Under this method, a plurality of frequencies are applied to a first electrode. This application is performed once while the second electrode and the common electrode are connected by a short circuit, and then again when the second electrode and the common electrode are capacitively connected or open circuited. During each application of the plurality of frequencies to the crystal, the phase response for the output of the resonator circuit is monitored. Then the time response of the crystal is determined. Next, the time delay relative maxima for the time response is determined. Finally, the frequencies at which the time delay relative maxima occur are determined.Type: GrantFiled: January 9, 1995Date of Patent: January 14, 1997Assignee: Xtal Technologies, Ltd.Inventors: Gerald E. Roberts, Michael E. Roberts