Spurious Signal Reduction Patents (Class 333/143)
  • Patent number: 9860646
    Abstract: There is disclosed herein a transducer for acoustic communications through a series arrangement of fluid and solid media, the transducer comprising: —a signal processor configured to implement a communications scheme at and around a center frequency of at least 1 MHz; a piezoelectric element for activation in accord with the communications scheme; an electrode electrically connected to the signal processor, and being attached to the piezoelectric element; and a substrate, having the piezoelectric element mounted thereon, wherein an aspect of the electrode at the piezoelectric element is approximately equal to the acoustic wavelength of an acoustic wave in the substrate at the center frequency. There is further disclosed a remote monitoring device employing at least one of the transducers described, in concert with a further transducer. Still further, there is disclosed a method of communicating using the transducer described herein.
    Type: Grant
    Filed: October 17, 2012
    Date of Patent: January 2, 2018
    Assignee: BAE Systems plc
    Inventors: John Martin Bagshaw, Lionel William John Kent, Christophe Arthur Paul Boulet
  • Patent number: 9786266
    Abstract: Methods and systems for acoustically treating material are described. Acoustic energy is emitted into a waveguide having a wall with a shape that tapers away from the acoustic source. The wall may have a substantially conical or parabolic shape. When emitted therein, the waveguide causes convergence of the acoustic energy so as to form an acoustic focal zone at a vessel. In some embodiments, a substantial portion of the acoustic focal zone is located outside of the internal volume defined by the waveguide.
    Type: Grant
    Filed: December 10, 2013
    Date of Patent: October 10, 2017
    Assignee: Covaris, Inc.
    Inventors: James A. Laugharn, Jr., Xiaoyin He
  • Patent number: 9191125
    Abstract: In apparatus for the acoustic transmission of power or data through a solid barrier such as a ships hull, assembly of an acoustic transducer to the hull is facilitated by bonding it first to an intermediate element by a thin layer of bonding adhesive and then bonding the intermediate element to the barrier using a second bonding layer. Acoustic matching of the transducer to the intermediate element is achieved by the thin layer, and the mechanically more robust base of the intermediate element can be rubbed on the barrier surface to displace or abrade away any unwanted debris or imperfections which might otherwise prevent the achievement of a thin second bonding layer. This makes the mounting and bonding process more tolerant of imperfections in the barrier surface due to either surface defects or particulate contamination. The transmit and receive transducers may be positioned relative to each other so as to suppress or attenuate multiple-transit signals.
    Type: Grant
    Filed: September 6, 2010
    Date of Patent: November 17, 2015
    Assignee: BAE SYSTEMS PLC
    Inventors: John Martin Bagshaw, Lionel William John Kent
  • Patent number: 7745521
    Abstract: An acoustic (sound or ultrasound) wave transmitter having a plurality of waveguides is described, and a method of making such a transmitter is described. Each waveguide may have a cladded core. The cladded core is capable of transmitting acoustic wave energy from a first end surface to a second end surface of the cladded core. The waveguides may be substantially fixed relative to each other by a binder. The binder may be formed by fusing the claddings together, potting a material between the waveguides and/or mechanically holding the waveguides.
    Type: Grant
    Filed: June 11, 2007
    Date of Patent: June 29, 2010
    Assignee: Ultra-Scan Corporation
    Inventors: John K. Schneider, Jack C. Kitchens
  • Patent number: 6515554
    Abstract: Electrodes are formed on both top and bottom surfaces of a dielectric plate and grounded coplanar lines, as transmission lines, are formed on the top surface of the dielectric plate. A plurality of micro-strip lines, each composed of high-impedance lines and low-impedance lines alternately connected in series, is arranged at a pitch shorter than the wavelength of a wave traveling along the grounded coplanar lines. A spurious mode propagation blocking circuit thus constructed prevents a spurious mode wave, such as a parallel-plate mode, from traveling.
    Type: Grant
    Filed: September 26, 2001
    Date of Patent: February 4, 2003
    Assignee: Murata Manufacturing Co. Ltd
    Inventors: Yohei Ishikawa, Kenichi Iio, Takatoshi Kato, Koichi Sakamoto
  • Patent number: 6323740
    Abstract: Electrodes are formed on both top and bottom surfaces of a dielectric plate and grounded coplanar lines, as transmission lines, are formed on the top surface of the dielectric plate. A plurality of micro-strip lines, each composed of high-impedance lines and low-impedance lines alternately connected in series, is arranged at a pitch shorter than the wavelength of a wave traveling along the grounded coplanar lines. A spurious mode propagation blocking circuit thus constructed prevents a spurious mode wave, such as a parallel-plate mode, from traveling.
    Type: Grant
    Filed: July 16, 1999
    Date of Patent: November 27, 2001
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Yohei Ishikawa, Kenichi Iio, Takatoshi Kato, Koichi Sakamoto
  • Patent number: 5828274
    Abstract: Ultrasonic buffer rods are useful for on-line process control of industrial material processes at elevated temperatures. In order to increase the signal-to-noise ratio in the reflected ultrasonic waves revealing the information of the condition of the materials being processed, clad ultrasonic waveguides consisting of a tapered or uniform core and a cladding are proposed. The core is made of a low ultrasonic loss material. Preferably, the cladding has a higher ultrasonic velocity than the core. The cladding may be thermally sprayed over the core. The waveguides are simple, rugged, machinable and operable at elevated temperatures.
    Type: Grant
    Filed: May 28, 1996
    Date of Patent: October 27, 1998
    Assignee: National Research Council of Canada
    Inventors: Chen-Kuei Jen, Jean-Gabriel Legoux
  • Patent number: 5559481
    Abstract: A SAW filter includes a first SAW resonator having a pair of terminals and a predetermined resonance frequency (f.sub.rp), the first SAW resonator being provided in a parallel arm of the SAW filter. A second SAW resonator has a pair of terminals and a predetermined resonance frequency (f.sub.rs) approximately equal to a predetermined antiresonance frequency of the first SAW resonator (f.sub.ap). The second SAW resonator is provided in a series arm of the SAW filter. An inductance element is connected in series to the first SAW resonator.
    Type: Grant
    Filed: October 23, 1992
    Date of Patent: September 24, 1996
    Assignee: Fujitsu Limited
    Inventors: Yoshio Satoh, Osamu Ikata, Tsutomu Miyashita, Takashi Matsuda, Mitsuo Takamatsu
  • Patent number: 5241287
    Abstract: Acoustic buffer rods are useful in the nondestructive ultrasonic evaluation of materials. In order to reduce the occurrence of spurious signals in the reflected acoustic waves forming an acoustic "image" of a sample, it is proposed to design buffer rods such that their radial acoustic velocity profile is graded, preferably having a parabolic shape. The lowest acoustic velocity of the buffer rod is in its center, i.e. at the longitudinal axis of the rod. This design is applicable to both uncladded buffer rods as well as to the core of cladded ones.
    Type: Grant
    Filed: December 2, 1991
    Date of Patent: August 31, 1993
    Assignee: National Research Council of Canada
    Inventor: Cheng-Kuei Jen
  • Patent number: 5173667
    Abstract: A multiple-reflection, long-path wave transmission device is fabricated from a single crystal silicon plate by micromachining straight walled rectangular cavities into the plate to reflect ultrasonic waves along an extended transmission path defined by the rectangular cavities. An input transducer is coupled to the silicon plate to introduce ultrasonic waves into the plate in response to an input signal. The ultrasonic waves travel in the silicon plate along the transmission path defined by the straight walled reflective cavities. An output transducer is similarly coupled to the silicon plate to receive the ultrasonic waves at the completion of the transmission path and to generate an output signal representative thereof. Additional sloped wall cavities are formed in the silicon plate to border the extended transmission path. The sloped wall cavities prevent cross coupling of waves traveling in different portions of the path and absorb energy traveling in undesired directions and modes.
    Type: Grant
    Filed: February 19, 1991
    Date of Patent: December 22, 1992
    Assignee: Ford Motor Company
    Inventor: Allen H. Meitzler
  • Patent number: 4821004
    Abstract: Methods are disclosed for the elimination of spurious echos in electro-acoustic delay lines using bulk waves. The method consists in etching an array, formed of hollows and peaks on a reflecting side of a delay line of this type, the difference in height between the said hollows and peaks giving the waves reflected from them a phase difference such that the signals induced by the spurious echos in the transducer cancel one another out. The method can be used to improve the characteristics of a delay line using bulk waves without excessively complicating its manufacture.
    Type: Grant
    Filed: January 14, 1988
    Date of Patent: April 11, 1989
    Assignee: Thomson-CSF
    Inventors: Philippe Defranould, Marc Verroust
  • Patent number: 4819215
    Abstract: An electrical signal transfer element is disclosed. This element consists of a ultrasonic wave solid propagation medium, input and output transducers and backing members. The ultrasonic wave solid propagation medium has a ultrasonic wave propagation distance which is shorter than a distance between main surfaces or a distance between side surfaces. The input and output transducers attached to ultrasonic wave signal input and output surfaces of the foregoing propagation medium serve to convert an input electric signal into a ultrasonic wave and to convert this ultrasonic wave into an output electric signal. The backing members are joined to surfaces opposite to joint surfaces of the input and output transducers to the propagation medium.
    Type: Grant
    Filed: January 29, 1987
    Date of Patent: April 4, 1989
    Assignee: Showa Electric Wire & Cable Co., Ltd.
    Inventors: Takeo Yokoyama, Hidetoshi Yamazoe
  • Patent number: 4733204
    Abstract: An ultrasonic-wave delay line element comprises a pentagonal delay medium body formed by cutting at an angle of about 45.degree. a part of the major surface defined by a rectangular shape having two longer sides and two shorter sides, and has a pair of input and output electric-mechanic transducers provided on a side A formed by cutting the major surface. The input and output electric-mechanic transducers are attached to the cut side A at positions near longer side C contiguous to the cut side A with respect to the center of the cut side A; a reflection point for a sound-wave is provided in the cut side A while no reflection point is provided in a shorter side B contiguous to the out side A; two or more reflection points are provided in the longer side C; two reflection points are formed in the other shorter side D isolated from the cut side A; and four or more reflection points are provided in the other longer side E isolated from the cut side A.
    Type: Grant
    Filed: March 24, 1986
    Date of Patent: March 22, 1988
    Assignee: Asahi Glass Company Ltd.
    Inventors: Michihiko Uemura, Naomitsu Umemura, Tunaomi Fukui
  • Patent number: 4691178
    Abstract: An ultrasonic delay line including an input transducer for producing a sound wave depending on an input voltage, a delay medium for transmitting the sound wave produced by the input transducer and an output transducer for receiving the sound wave transmitted in the delay medium has a shape such that sound waves transmitted in the delay medium are misdirected with respect to the output transducer by a predetermined amount. As a result, a substantial part of a main signal is input into the output transducer, whereas a substantial part of the sound waves having the third or higher harmonic component with respect to the main signal misses the output transducer due to the higher directivity of these higher frequency components in the delay medium.
    Type: Grant
    Filed: April 23, 1986
    Date of Patent: September 1, 1987
    Assignee: Asahi Glass Company Ltd.
    Inventors: Takeshi Okada, Haruto Hashimoto, Michihiko Uemura
  • Patent number: 4684906
    Abstract: There is disclosed a solid ultrasonic delay line comprising a solid ultrasonic delay medium on which polygonal multiple-reflective surfaces are formed. An input transducer for radiating longitudinal waves is disposed on one of the reflective surfaces. The longitudinal waves are transformed into transverse waves by other one of the reflective surfaces and then reconverted by yet other one of the reflective surfaces into longitudinal waves which enter an output transducer disposed on still other one of the reflective surfaces. Ultrasound absorbers cover at least portions of the main boundary surfaces perpendicular to the reflective surfaces. Spurious waves of the longitudinal waves radiated from the input transducer are transformed by the main boundary surfaces into transverse waves which enter the absorbers.
    Type: Grant
    Filed: May 28, 1986
    Date of Patent: August 4, 1987
    Assignee: Showa Electric Wire & Cable Co., Ltd.
    Inventor: Takeo Yokoyama
  • Patent number: 4525692
    Abstract: An ultrasonic delay line fabricated from a solid transmission medium is configured to provide (2n+3) reflections of the desired signal at five reflective facets of an irregular polygon. The reflective pattern tends to allow maximum surface area available for the deposition of absorbent material so as to thereby and otherwise minimize spurious transmissions. In an alternative embodiment, a bifurcated delay line includes two branches physically coupled at one end and electrically coupled through a pair of transducers so that approximately half the height and width of transmission medium is required in order to effectuate a predetermined time delay.
    Type: Grant
    Filed: April 22, 1983
    Date of Patent: June 25, 1985
    Assignee: GTE Products Corporation
    Inventor: Roger G. Claes
  • Patent number: 4510470
    Abstract: A transmission-type electro-acoustic delay line comprises an acoustic medium delimited by a cylindrical lateral surface, a plane terminal surface on which are fixed two symmetrical transducers, and a focusing terminal surface in the form of a spherical cap. The angle formed by the plane surface and the axis of revolution of the spherical cap is less than 90.degree. by an angle such that the incident acoustic wave undergoes a single reflection on the focusing cap and such that the reflected acoustic wave is concentrated at the level of the output transducer.
    Type: Grant
    Filed: February 22, 1983
    Date of Patent: April 9, 1985
    Assignee: Thomson CSF
    Inventors: Jean C. Resneau, Jean Puyhaubert, Evelyne Da Silva, Claude Lamontagne
  • Patent number: 4499439
    Abstract: A bifurcated electroacoustic delay line exhibits at least a pair of substantially identical branches, each assuming a generally pentagonal profile. Each branch is configured to provide (2n+3) reflections of a desired wave at five reflective facets. The reflective pattern so defined tends to maximize the surface area available for the deposition of absorbent material so as to thereby and otherwise minimize spurious transmissions.The branches are physically joined along at least one side and include transducers for the conversion of electrical energy to acoustical energy. An inductance connected between two such transducers couples energy from one branch to the other.
    Type: Grant
    Filed: April 22, 1983
    Date of Patent: February 12, 1985
    Assignee: GTE Products Corporation
    Inventor: Roger G. Claes
  • Patent number: 4488127
    Abstract: A bifurcated electroacoustic delay line exhibits at least a pair of substantially identical branches, each assuming a generally pentagonal profile. Each branch is configured to provide (2n+3) reflections of a desired wave at five reflective facets. The reflective pattern so defined tends to maximize the surface area available for the deposition of absorbent material so as to thereby and otherwise minimize spurious transmissions.The branches are physically joined along one side so as to define an area of bifurcation. A plurality of piezoelectric transducers are bonded at the area of bifurcation in a pairwise laterally adjacent manner. An inductance couples electrical energy from the output transducer of the first branch to the input transducer of the second branch.
    Type: Grant
    Filed: April 22, 1983
    Date of Patent: December 11, 1984
    Assignee: GTE Products Corporation
    Inventor: Roger G. Claes
  • Patent number: 4488128
    Abstract: A bifurcated electroacoustic delay line includes first and second branches of a transmission medium, the branches being joined along respective common sides. Bonded to the common sides of the branches are respective first and second input and first and second output transducers, the transducers arranged so that the input transducers are positioned laterally adjacent each other and the output transducers are analogously positioned. An inductance diagonally couples the first output transducer to the second input transducer permits frequency tuning of the delay line.Diagonal coupling via an inductance operates to mitigate the effects of spurious responses derived from the divergence of electroacoustic waves between laterally adjacent tranducers and, collaterally, permits tuning of the delay line composite frequency response.
    Type: Grant
    Filed: April 22, 1983
    Date of Patent: December 11, 1984
    Assignee: GTE Products Corporation
    Inventor: John A. Odozynski
  • Patent number: 4467295
    Abstract: There is disclosed a solid ultrasonic delay line which comprises a delay medium having two parallel major faces and at least three end faces intersecting the major faces, an input transducer bonded to one of the end faces and polarized in a direction parallel to the major faces for transmitting an ultrasonic signal in a shear mode into the delay medium, and an output transducer bonded to one of the end faces for converting the ultrasonic signal having propagated through the delay medium into an electrical signal. The input and output transducers have boundary surfaces lying flush with the two major faces of the delay medium, the major faces and the boundary surfaces being ground to a surface roughness which is one-twentieth or smaller of the wavelength of the ultrasonic signal propagating through the delay medium.
    Type: Grant
    Filed: September 27, 1982
    Date of Patent: August 21, 1984
    Assignee: Showa Electric Wire & Cable Co., Ltd.
    Inventors: Takeo Yokoyama, Ichiya Imai, Hideaki Asaoka
  • Patent number: 4392115
    Abstract: The volume magnetostatic wave device comprises a unidirectional-radiation transducer composed of equidistant microstrips connected to a polyphase transformer and coupled to a ferrimagnetic wafer which is subjected to a polarizing magnetic field.
    Type: Grant
    Filed: April 13, 1981
    Date of Patent: July 5, 1983
    Assignee: Thomson-CSF
    Inventors: Gerard Volluet, Pierre Hartemann
  • Patent number: 4349794
    Abstract: Acoustic wave devices employing shallow bulk acoustic waves rather than surface acoustic waves, to provide higher frequencies of operation and other significant advantages, such as less susceptibility to aging and less sensitivity to surface contamination. In each embodiment of the invention, a transmitting transducer and a receiving transducer are oriented on the surface of an anisotropic piezoelectric crystal to achieve substantial coupling of shallow bulk acoustic waves and essentially zero coupling of surface acoustic waves. In one embodiment of the invention, various types of grating filters utilize shallow bulk acoustic waves, and a set of parallel mechanical or electrical discontinuities at or near the surface of the crystal provide reflection of acoustic energy at a frequency determined by the spacing of the discontinuities. Uniformly spaced gratings provide bandpass filter operation, and gratings with graduated spacings provide for frequency compression or expansion.
    Type: Grant
    Filed: October 24, 1978
    Date of Patent: September 14, 1982
    Assignee: TRW Inc.
    Inventors: Reynold S. Kagiwada, Kuo-Hsiung Yen, Ke-Li Wang, Kei F. Lau, Donald L. Lochhead, James A. Leaverton
  • Patent number: 4316161
    Abstract: Electroacoustic apparatus is described incorporating a substrate having a transducer on an upper surface and a transducer on a lower surface positioned for receiving bulk acoustic waves; substrate taper along with transducer geometry are combined to provide bulk acoustic signals in the near zone or Fresnel zone which provide for phase and amplitude cancellation of a triple transit signal.The invention overcomes the problem of spurious triple transit signals in bulk mode acoustic delay lines for input signals having a wide bandwidth, such as an octave, and where the delay times are short such that the bulk acoustic wave remains in the near zone or the transition region between the near zone and far zone.
    Type: Grant
    Filed: September 8, 1980
    Date of Patent: February 16, 1982
    Assignee: Westinghouse Electric Corp.
    Inventors: Robert A. Moore, Robert N. Sundelin
  • Patent number: 4301431
    Abstract: In a miniaturized delay line constituted by a single crystal through which an ultrasonic beam passes and by two electroacoustic transducers, the direct coupling between the input and the output of the delay line is attenuated by means of a molded shielding element of araldite loaded with silver. The molded element is placed around the output transducer as well as the lead which connects the transducer to one of the connector-pins of the base of the casing containing the delay line.
    Type: Grant
    Filed: March 25, 1980
    Date of Patent: November 17, 1981
    Assignee: Thomson-CSF
    Inventors: Jean Puyhaubert, Claude Jacquemin
  • Patent number: 4242653
    Abstract: Electroacoustic apparatus is described incorporating a substrate having a plurality of transducers on an upper surface and a plurality of transducers on a lower surface each positioned for receiving bulk acoustic waves from a respective transducer on the upper surface wherein each receiving transducer has a predetermined acoustical path length from its respective transducer on the upper surface, means for coupling an input signal to the transducers on the upper surface, and means for coupling an output signal from the transducers on the lower surface. The invention further provides a plurality of bulk mode acoustic delay lines having predetermined acoustical path lengths which are coupled in parallel to suppress the triple transit signal.The invention overcomes the problem of spurious triple transit signals in bulk mode acoustic delay lines for input signals having a wide bandwith, such as an octave.
    Type: Grant
    Filed: May 8, 1979
    Date of Patent: December 30, 1980
    Assignee: Westinghouse Electric Corp.
    Inventor: Robert A. Moore