Receiver Circuitry Patents (Class 367/135)
  • Patent number: 6356510
    Abstract: A novel method and apparatus for signal processing are described which discriminate between signals and noise based on the magnitude of the phase fluctuations. In an embodiment of the invention, the governing equations of the process adaptively change in response to the phase and amplitude characteristics of the signals being received for processing. In an embodiment of the invention, an automatic detection method and apparatus is described which has the capability to alert an operator of the presence of signals having phase fluctuation characteristics which match a set of preset conditions (e.g. small fluctuations, medium fluctuations, or large fluctuations).
    Type: Grant
    Filed: February 4, 2000
    Date of Patent: March 12, 2002
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Ronald A. Wagstaff, Jackson A. Mobbs
  • Publication number: 20020012289
    Abstract: A multidimensional beamforming device that performs consecutive one-dimensional operations. For example, beamsteering for a two-dimensional array can be include a projection of a beam onto each of the respective axes of the array. In such a device, a first beamforming processing element is used to form multiple beams for each array output along a given row. In a preferred embodiment, sequential output vectors from the first processing element are then applied to a transposing or corner turning memory and the data are reformatted such that all elements on a given column of the array are applied to a second beam forming processing element.
    Type: Application
    Filed: August 2, 2001
    Publication date: January 31, 2002
    Applicant: TeraTech Corporation
    Inventors: Jeffrey M. Gilbert, Alice M. Chiang, Steven R. Broadstone
  • Patent number: 6310554
    Abstract: A severe weather detection apparatus for detecting severe weather and method of detecting and warning of approaching severe weather conditions is provided. The severe weather detector apparatus includes a barometric pressure sensor and computerized means for calculating the rate of change in the barometric pressure. By monitoring and deriving a value representative of the rate of change in the barometric pressure over time, a threshold is established and compared to the current rate of change in the barometric pressure. The derived rate of change is compared to a value stored in the device which reflects approaching severe weather conditions. Rates of change which may indicate the approach of severe weather activate a voice-enunciated alarm that announces the potentially dangerous barometric activity. The severe weather detection apparatus is portable and suitable for battery power and installation in the same manner as a home smoke alarm or carbon monoxide detector.
    Type: Grant
    Filed: August 13, 1999
    Date of Patent: October 30, 2001
    Inventor: Wade J. Carrell
  • Patent number: 6307811
    Abstract: In the method according to the invention, several adjacent synchronized ultrasonic sensors automatically generate a clock signal with measurement clocks (M1, M2, M3). The transmission pulses (S1, S2, S3) of three ultrasonic sensors are generated with changing transmission pulse offset (d1, d2, d3) with respect to the respective measurement clocks (M1, M2, M3). Thereby, extrinsic echo signals of adjacent ultrasonic sensors can be masked out since only these echo signals change their position relative to the transmission pulses (S1, S2, S3). In contrast, the actual sought echo signal does not change its respective position relative to the transmission pulse (S1, S2, S3).
    Type: Grant
    Filed: September 29, 2000
    Date of Patent: October 23, 2001
    Assignee: Siemens AG
    Inventor: Ernst Luber
  • Patent number: 6288974
    Abstract: A system for detecting an object of interest through a medium such as the atmosphere or ocean employs a reference object from which a reference signal emanates. A detector detects and transforms the reference signal into a transformed reference signal and further detects and transforms an object signal emanating from an object of interest into a transformed object signal. The object signal may be radiated, re-radiated, or scattered from the object of interest. An image processor generates a corrected image signal by applying an image transfer function to convolve the transformed object signal. Then a display presents a corrected image of the object of interest in response to receiving the corrected image signal.
    Type: Grant
    Filed: March 30, 1999
    Date of Patent: September 11, 2001
    Assignee: The United States of Americas as represented by the Secretary of the Navy
    Inventor: Robert S. Nelson
  • Patent number: 6269052
    Abstract: The circuit and the method serve to transmit a transmission signal to a transducer and to receive a reception signal from the transducer. The transmitter and the receiver are each alternatively coupled to the transducer and decoupled from one another. The coupling and decoupling is thereby achieved by a total of three nonlinear two-terminal networks (Z1, Z2, Z3). The transmitter is connected to the transducer via a bipolar voltage limiter and the receiver is connected to the transducer via a bipolar current limiter.
    Type: Grant
    Filed: August 16, 1999
    Date of Patent: July 31, 2001
    Assignee: Siemens Aktiengesellschaft
    Inventor: Ralph Oppelt
  • Patent number: 6262943
    Abstract: A method and an apparatus for distinguishing systematic artifacts from noise involves localizing functional noise in the vicinity of predicted functional peaks. The method is particularly relevant to detection and tracking of time-varying signals. An apparatus implementing such an application of the method comprises a detection system (50) which monitors each component of a multi-component periodic signal via its basis repeat unit: a cyclet, of periodicity &tgr;. The signal is digitized and clocked through the system (50) in segments. A cyclet remover (62) subtracts predicted values of previously detected cyclets from the incoming signal segment to produce a residual signal. A cyclet detector (60) uses a sliding window procedure to detect further cyclets in this residual and to measure their amplitude profiles {overscore (b)}(&tgr;) and periodicities (&tgr;).
    Type: Grant
    Filed: January 28, 2000
    Date of Patent: July 17, 2001
    Assignee: The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland
    Inventor: Ira J Clarke
  • Patent number: 6208589
    Abstract: The invention relates to a method of screening an acoustic signal or a spectrum line of maximum energy transmitted by a “target” that can be submerged at sea, from among a multitude of acoustic signals coming from any noise generators radiating acoustic signals of the same type with higher energy than energy E, employing, for example, (1) a set of N submersible acoustic pickups identically parameterized in surveillance mode, designed to detect the presence of the signal or a desired spectrum line, with the set of N pickups defining any number of surveillance cells with two adjacent pickups, each pickup being associated with one or more target detection regions defined as the geographic areas within which the presence of the “target” is deemed detectable and outside which the “target” is deemed nondetectable, and (2) a maximum number Nmax of pickups relating to one or more “special” areas (selected from a set of elementary geographic areas) of a given surveillanc
    Type: Grant
    Filed: April 1, 1999
    Date of Patent: March 27, 2001
    Assignee: Delegation Generale pour l'armement
    Inventor: Charles Bertolino
  • Patent number: 6201764
    Abstract: A method and an apparatus are provided for matching the response of hydrophones 22 to the response of geophones 24 and significantly reducing response variations between hydrophones caused by inherent characteristics. The method includes the steps of determining a capacitance 66 for each of the hydrophones 22 in an operating environment, configuring a filter 36 based on the capacitance 66, and modifying a response of a channel of the hydrophone 22 using the filter 36. The apparatus includes an acquisition unit 20 having a geophone 24 and a hydrophone 22, a recording unit 30, a processing unit 31 and a filter 36 for correcting for variation between hydrophones 22 and changing a first order low frequency response of the hydrophone 22 to appear like a second order response like that of the geophone 24.
    Type: Grant
    Filed: October 31, 1997
    Date of Patent: March 13, 2001
    Assignee: Input/Output, Inc.
    Inventors: Charles Geoffrey Rice, Paul Ellington Carroll, Thomas Glen Ragan
  • Patent number: 6173074
    Abstract: An acoustic signature recognition and identification system receives signals from a sensor placed on a designated piece of equipment. The acoustic data is digitized and processed, via a Fast Fourier Transform routine, to create a spectrogram image of frequency versus time. The spectrogram image is then normalized to permit acoustic pattern recognition regardless of the surrounding environment or magnitude of the acoustic signal. A feature extractor then detects, tracks and characterizes the lines which form the spectrogram. Specifically, the lines are detected via a KY process that is applied to each pixel in the line. A blob coloring process then groups spatially connected pixels into a single signal object. The harmonic content of the lines is then determined and compared with stored templates of known acoustic signatures to ascertain the type of machinery. An alert is then generated in response to the recognized and identified machinery.
    Type: Grant
    Filed: September 30, 1997
    Date of Patent: January 9, 2001
    Assignee: Lucent Technologies, Inc.
    Inventor: Anthony Peter Russo
  • Patent number: 6163267
    Abstract: The invention relates to a device for measuring noise comprising a sensor circuit having at least two sensors, an ambient noise eliminating circuit and a signal processing circuit. All the sensors are set to detect the ambient or background noise, however the source noise is positioned for detection by one of the sensors. The output of the sensor circuit is connected to the input of the ambient noise eliminating circuit where the ambient noise is eliminated from the noise signal leaving only a signal of the noise source. The signal processing circuit receives the signal of the measured noise, which is rectified and amplified, and then processed in the comparator circuit to determine whether the noise level is acceptable or not. The result is displayed through the display circuit comprising a plurality of LEDs.
    Type: Grant
    Filed: May 28, 1999
    Date of Patent: December 19, 2000
    Assignee: Sunonwealth Electric Machine Industry Co., Ltd.
    Inventor: David Su
  • Patent number: 6163504
    Abstract: A signal detector for monitoring sound signals comprises a first sensor operative in response to sound signals to produce a first electrical signal, first processing circuitry operative in response to the first electrical signal to amplify it and produce a first input signal, digitally controlled oscillator circuitry operative to produce a reference signal at a selected reference signal frequency, a mixer operative to receive the first input signal and reference signal to produce a mixed composite signal, conditioning circuitry operative in response to the mixed composite signal to produce a first amplified output signal, and a first output device for producing a first display in response to the first amplified output signal. A methodology is also provided for monitoring sound signals in order to indicate a presence of those signals having frequencies within a selected range.
    Type: Grant
    Filed: February 15, 2000
    Date of Patent: December 19, 2000
    Assignee: Radiaulics, Inc.
    Inventors: Nikolaos I. Komninos, Arthur Hughes
  • Patent number: 6141294
    Abstract: A data acquisition system receives an analog input signal comprising a pllity of octavely-nested components including a base octave and a selected number of higher-level octaves, and transmits digital data words representative of each component over a channel. The data acquisition system includes a data transmission system and an interface. The data transmission controller generates transmission strobes signals defining a series of octave transmission cycles each associated with one of said octaves, each octave transmission cycle having a series of octave strobe states including at least one octave strobe state associated with the base octave and successively higher numbers of octave strobe states associated with successively higher-level octaves. The transmission strobe states associated with each octave are uniformly distributed during each octave transmission cycle.
    Type: Grant
    Filed: March 10, 1999
    Date of Patent: October 31, 2000
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: Steven D. Jette
  • Patent number: 6122224
    Abstract: A receiver and method are disclosed that improves signal detection in a mipath environment wherein the desired reflected acoustic pulse is degraded by multipath reflections and embedded in noise. The invention provides a receiver that repetitively processes the received signal. The receiver includes separate signal processors, such as parallel configured quadrature signal processors, wherein each processor operates over different, and preferably contiguous, time intervals. After each repetition, the processing time interval for each processor is changed. The outputs of the processors are combined, such as by summing, and applied to a detector, such as a threshold detector, for each processing repetition to determine if the transmitted pulse is detected. The receiver continues processing the received signal until a predetermined number of time intervals have been processed without detection of a pulse or until the reflected pulse is detected.
    Type: Grant
    Filed: October 8, 1998
    Date of Patent: September 19, 2000
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: Robert C. Higgins
  • Patent number: 6122312
    Abstract: An apparatus for accurately transmitting and receiving acoustic waves indoors is provided. The apparatus contains a microphone, a speaker, a processing circuit, a first amplifier, a second amplifier, and a power control circuit. The microphone converts an input acoustic wave into an electric signal, and the speaker generates an output acoustic wave based on input data. The processing circuit processes the electric signal to produce processed data and outputs the input data to drive the speaker. The first amplifier receives a power signal and detects if a starting signal is contained in the electric signal output from the speaker. Then, the amplifier outputs a first detection signal when the starting signal is detected and outputs the power signal when the first detection signal is output. The second amplifier receives the power signal from the first amplifier and detects if a non-starting signal is contained in the electric signal when the starting signal is detected.
    Type: Grant
    Filed: November 19, 1999
    Date of Patent: September 19, 2000
    Assignee: SI Corporation
    Inventor: Shirai Shiro
  • Patent number: 6104672
    Abstract: An apparatus and method for filtering the effects of large amplitude signal fluctuations from elements of the cross-spectral density matrix of a detor array. The outputs of the array are sampled T times, and the values of each element of the matrix formed by using: ##EQU1## where Z.sub.li is the complex output of an sensor of the array at time i; Z*.sub.mi is the complex conjugate of the output of an array sensor at said time i; and k is an integer greater than 1. Because of the exponent k, small, relatively constant, terms will dominate, reducing the effect of large amplitude fluctuations. Preferably, the above value will be scaled according to: ##EQU2## which, besides being similarly filtered by the exponential terms, the resultant matrix element will have a magnitude corresponding to the actual power of the detected signal, after filtering.
    Type: Grant
    Filed: April 30, 1998
    Date of Patent: August 15, 2000
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: Ronald A. Wagstaff
  • Patent number: 6104984
    Abstract: In accordance with the present invention, a method for obtaining frequency nformation about a given data set is realized. The method comprises the steps of providing a processing unit; inputting a raw data set into the processing unit; optionally removing at least one trend from the raw data; ordering the raw data; estimating power spectral density using an eigenanalysis approach and the inputted raw data and the ordered raw data; simultaneously estimating the power spectral density using the raw data and a periodogram; generating a time-series representation of the raw data to which curve fitting is applied; comparing the results from the power spectral density estimating steps and the time-series representation generating step to determine if any frequencies suggested by the eigenanalysis approach estimating step are valid; and generating an output signal representative of each valid frequency.
    Type: Grant
    Filed: June 26, 1998
    Date of Patent: August 15, 2000
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Steven W. Thorpe, Francis P. Whitsitt-Lynch
  • Patent number: 6094150
    Abstract: In a noise measuring system comprising a microphone array and a directivity forming section for controlling the direction of directivity of the microphone array, the directivity forming section includes delay section and adding section, and the optimal value of a delay time of the delay section is set in such a manner that a noise isolation characteristic for causing any mobile noise generator not targeted for noise measurement to come off a directional plane or a directional line formed in the direction of directivity of the microphone array and a deterioration characteristic of the directivity of the microphone array balance with each other.
    Type: Grant
    Filed: August 6, 1998
    Date of Patent: July 25, 2000
    Assignee: Mitsubishi Heavy Industries, Ltd.
    Inventors: Keizo Ohnishi, Kazufumi Ikeda, Tetsuya Nagao
  • Patent number: 6058076
    Abstract: The present invention generally relates to procedures and apparatus for monitoring incoming signals to detect the presence of selected target signals contained within the universe of signals received. More particularly, the present invention is directed to monitoring audio signals to detect selected ultrasonic and sonic signals in an ambient environment. Thus, the present invention is even more specifically directed to leak detectors and bearing wear indicators and methods for detecting sound signals which either travel in the air or are present in solids.
    Type: Grant
    Filed: December 8, 1997
    Date of Patent: May 2, 2000
    Inventor: Nikolaos I. Komninos
  • Patent number: 6051027
    Abstract: A layered structure is divided into a plurality of regions. Transmission line equivalents (Green's functions) in the spectral domain are formed between all regions within the layered structure. The spectral domain Greens' function are converted to the spatial domain using a near field and a far field computed for those regions part of a component within the layered structure. The far field is extracted from a compressed database computed from the transmission line equivalents and descriptive of the layered structure. The near field is computed using a prioritization mechanism. Priority is assigned in accordance with the amplitude of a source and the length of the path between regions of interest.Once the physical characteristics of the layers used in the fabrication process of the IC are identified, the database used for computation of the far field is compiled and compressed, and remains unchanged for each new parameter extraction.
    Type: Grant
    Filed: July 16, 1998
    Date of Patent: April 18, 2000
    Assignee: Lucent Technologies
    Inventors: Sharad Kapur, David Esley Long, Jingsong Zhao
  • Patent number: 6014897
    Abstract: A method and an apparatus for enhancing the side-lobe performance of a sparse ultrasonic transducer array using harmonic imaging to reduce all beam sidelobe (including grating lobe) levels. Harmonic imaging consists of using the active transducer elements to transmit an ultrasound signal (wideband or narrowband) of center frequency f.sub.0 and receive at one or more harmonic frequencies nf.sub.0, where n.gtoreq.2.
    Type: Grant
    Filed: September 2, 1998
    Date of Patent: January 18, 2000
    Inventor: Larry Y. L. Mo
  • Patent number: 6011819
    Abstract: An acoustic communication apparatus includes a microphone/speaker for converting a power voltage and an aerial acoustic wave into an electric signal, and generating an acoustic wave corresponding to the input of data; a signal processing circuit for signal processing the electric signal output from the microphone/speaker in response to the input of the power voltage, the signal being received as data, the circuit outputting data responding thereto to thereby drive the microphone/speaker; a starting signal selection amplifier for always receiving the power voltage during a reception waiting mode, and detecting a starting signal having a predetermined frequency from the electric signal output from the speaker; a non-starting signal selection amplifier for receiving the power voltage in response to the detection of the starting signal, and selectively amplifying only a band excluding the frequency band of the starting signal; and a power voltage supply control circuit for supplying the power voltage to the signa
    Type: Grant
    Filed: July 19, 1996
    Date of Patent: January 4, 2000
    Assignee: SI Corporation
    Inventor: Shirai Shiro
  • Patent number: 5917776
    Abstract: A rugged ultrasonic sensor is provided which is capable of detecting objects in very close proximity to the sensor. This close proximity detection includes the detection of objects which are immediately adjacent the sensor housing. Such close range operation is achieved by tailoring the transducer to operate at previously undesirable conditions, including low Q and high frequency. Such operating conditions allow the resonating characteristics of the transducer not to interfere with close range operation.
    Type: Grant
    Filed: December 31, 1996
    Date of Patent: June 29, 1999
    Assignee: Honeywell Inc.
    Inventor: Donald Sirola Foreman
  • Patent number: 5903883
    Abstract: A likelihood of detecting a reflected signal characterized by phase discontinuities and background noise is enhanced by utilizing neural networks to identify coherency intervals. The received signal is processed into a predetermined format such as a digital time series. Neural networks perform different tests over arbitrary testing intervals to determine the likelihood of a phase discontinuity occurring in any such interval. An integration time generator subsequently uses this information to define a series of contiguous coherency intervals over the duration of the received signal. These coherency intervals are then used for piece-wise processing of the received signal by parallel quadrature receivers. The outputs are combined and processed for detecting the presence of the reflected signal.
    Type: Grant
    Filed: March 10, 1997
    Date of Patent: May 11, 1999
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Christopher M. DeAngelis, Robert C. Higgins
  • Patent number: 5886951
    Abstract: A method for enhancing signal-to-noise ratio and resolution of amplitude stable signals wherein underwater acoustic data is first collected with an array of hydrophones, and then the data is digitally sampled. After producing spectra of sequential time snapshots of the digitally-sampled data, the spectra are beamformed for a single frequency. Next the low resolution beamformer response is deconvolved from the data by use of a calculated beam response pattern for the hydrophone array, so that many high-resolution estimates are created for each time snapshot. Finally, the resulting high resolution estimates are reduced to a single estimate for each spatial bin across all of the time snapshots, and the high resolution, high gain results are displayed.
    Type: Grant
    Filed: August 27, 1997
    Date of Patent: March 23, 1999
    Inventors: Ronald A. Wagstaff, Susan D. Gardner
  • Patent number: 5878367
    Abstract: Traffic is monitored in individual lanes of a roadway as to vehicle count or presence, speed and direction of movement by mounting a microphone array high above the road surface, digitizing the output signals of the microphones, filtering, beamforming and storing the digitized signals to provide separate power histories for separate locations in individual lanes. These power histories are then analyzed to provide vehicle movement data for each lane.
    Type: Grant
    Filed: June 28, 1996
    Date of Patent: March 2, 1999
    Assignee: Northrop Grumman Corporation
    Inventors: Gregory Reid Lee, Yie-Ming Chen
  • Patent number: 5853364
    Abstract: A method and apparatus for reducing the effects of noise on a system for measuring physiological parameters, such as, for example, a pulse oximeter. The method and apparatus of the invention take into account the physical limitations on various physiological parameters being monitored when weighting and averaging a series of measurements. Varying weights are assigned different measurements, measurements are rejected, and the averaging period is adjusted according to the reliability of the measurements. Similarly, calculated values derived from analyzing the measurements are also assigned varying weights and averaged over adjustable periods. More specifically, a general class of filters such as, for example, Kalman filters, is employed in processing the measurements and calculated values. The filters use mathematical models which describe how the physiological parameters change in time, and how these parameters relate to measurement in a noisy environment.
    Type: Grant
    Filed: June 7, 1996
    Date of Patent: December 29, 1998
    Assignee: Nellcor Puritan Bennett, Inc.
    Inventors: Clark R. Baker, Jr., Thomas J. Yorkey
  • Patent number: 5798983
    Abstract: A novel multi-lane traffic monitoring system is based on detecting the acoustic signals motor vehicles create and radiate during operation. The system comprises an array of electro-acoustic sensors for converting impinging acoustic wavefronts to analog electrical signals; a circuit to acquire, perform signal frequency component discrimination, and digitize the electrical signals at the electro-acoustic sensor array output; a circuit to perform effective spatial discrimination in the up/down road direction and in the cross-road direction in real time; a circuit to perform vehicle detection for individual lanes and to estimate or measure pertinent parameters associated with each vehicle detection from each traveled lane; and a circuit to compute for each lane, pertinent traffic flow parameters from vehicle parameters for the purpose of providing a transportation system interface.
    Type: Grant
    Filed: May 22, 1997
    Date of Patent: August 25, 1998
    Inventors: John Patrick Kuhn, Binh C Bui, Gregory J Pieper
  • Patent number: 5784297
    Abstract: A method for finding a probability density function (PDF) and its statistical moments for an arbitrary exponential function of the form g(x)=.alpha.x.sup.m e.sup.-.beta.x.spsp.n,0<x<.infin., where .alpha., .beta., n>0, m>-1 are real constants in one-dimensional distributions and g(x.sub.1,x.sub.2, . . . ,x.sub.l) in the hyperplane. Non-linear regression analyses are performed on the data distribution and a root-mean-square (RMS) is calculated and recorded for each solution set until convergence. The basis function is reconstructed from the estimates in the final solution set and a PDF is obtained. The moment generating function (MGF), which characterizes any statistical moment of the distribution, is obtained using a novel function derived by the inventors and the mean and variance are obtained in standard fashion.
    Type: Grant
    Filed: January 13, 1997
    Date of Patent: July 21, 1998
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Francis J. O'Brien, Jr., Chung T. Nguyen, Bruce J. Bates
  • Patent number: 5781506
    Abstract: A method and system are provided for frequency filtering compressional wave nergy. An elastic cylinder is filled with a fluid that is selected based on a fluid density .rho..sub.i and a dilatational wave phase velocity c.sub.i thereof. When the elastic cylinder so-filled is subjected to a compressional wave propagating in a fluid environment, a first radial resonance frequency of the elastic cylinder is controlled by the fluid density .rho..sub.i and the dilatational wave phase velocity c.sub.i. Further tuning of the first radial resonance frequency can be achieved by adjusting the radial wall thickness of the elastic cylinder.
    Type: Grant
    Filed: May 29, 1997
    Date of Patent: July 14, 1998
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: Mark S. Peloquin
  • Patent number: 5781460
    Abstract: A chaotic signal processing system receives an input signal provided by a nsor in a chaotic environment and performs a processing operation in connection therewith to provide an output useful in identifying one of a plurality of chaotic processes in the chaotic environment. The chaotic signal processing system comprises an input section, a processing section and a control section. The input section is responsive to input data selection information for providing a digital data stream selectively representative of the input signal provided by the sensor or a synthetic input representative of a selected chaotic process. The processing section includes a plurality of processing modules each for receiving the digital data stream from the input means and for generating therefrom an output useful in identifying one of a plurality of chaotic processes. The processing section is responsive to processing selection information to select one of the plurality of processing modules to provide the output.
    Type: Grant
    Filed: June 28, 1996
    Date of Patent: July 14, 1998
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Chung T. Nguyen, Francis J. O'Brien, Jr., Sherry E. Hammel, Bruce J. Bates, Steven C. Nardone
  • Patent number: 5732045
    Abstract: A scheme for filtering noise from a signal, in which the noise fluctuates significantly in phase. The signal is sampled to produce N members of a time series and the phase of each signal extracted in the form of a magnitude and a phaser, i.e. for a time series .vertline.x.sub.1 .vertline.e.sup.i.theta..sbsp.1, .vertline.x.sub.2 .vertline.e.sup.i.theta..sbsp.2, . . . , .vertline.x.sub.N .vertline.e.sup.i.theta..sbsp.N, where .vertline.x.sub.n .vertline. is the magnitude of the nth member of the N time samples, and e.sup.i.theta..sbsp.N the phaser for the nth sample. The phasers are added to form a complex value s such thats=.SIGMA..sub.N=1.sup.N ?Re(e.sup.i.theta..sbsp.n)+iIm(e.sup.i.theta..sbsp.n)!.Phase noise which fluctuates strongly will tend cancel itself in the sum s, whereas phase resulting from a stable signal will tend to reinforce. Thus the scalar .vertline.s.vertline.
    Type: Grant
    Filed: December 31, 1996
    Date of Patent: March 24, 1998
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Ronald A. Wagstaff, Jacob George
  • Patent number: 5694373
    Abstract: A general-purpose, adaptable, device for interfacing acoustic and ultrasonic transducers to circuits for high resolution distance and motion measurement, and two-way communication. A generator signal (52) synchronizes to a sensing transducer signal (21), or a reference signal (23). A detector (20) provides a detected-cycle signal (22) and a detected-amplitude signal (24) from the signal being detected. Comparator (30) creates a comparator signal (32) from the detected-cycle and generator signals. A sustaining circuit provides flywheel operation during gaps. A driver (60) drives a radiating transducer. Options include: single or dual transducer operation, continuous or pulsed-burst operation, optimum frequency communication using low cost piezoelectric transducers, sonic wave frequency scanning, phase and amplitude modulation and demodulation, fast synchronization, detected vs reference signal comparison, and self-testing.
    Type: Grant
    Filed: August 13, 1996
    Date of Patent: December 2, 1997
    Inventor: Lawrence Garde
  • Patent number: 5689474
    Abstract: There is disclosed a digital frequency synthesizer which converts an ultrnic burst from an echo-ranging sonar system into a continuous signal having a frequency exactly equal to the frequency of the cycles making up the burst. This burst is detected and a number representing the period of this burst generated and transmitted to a first counter. A clock pulse train is generated and transmitted to a second counter. When the numbers in the first and second counters coincide, a single output pulse is generated and the second counter reset. When this cycle is repeated, the frequency of the resultant pulse train reflects any change in frequency of the cycles making up the bursts.
    Type: Grant
    Filed: October 15, 1968
    Date of Patent: November 18, 1997
    Assignee: The United States of America, as represented by the Secretary of the Navy
    Inventors: Rene N. Foss, Michael W. Manchester
  • Patent number: 5675553
    Abstract: The present invention comprises a method for filling in missing data intels in a quantized time-dependent data signal that is generated by, e.g., an underwater acoustic sensing device. In accordance with one embodiment of the invention, this quantized time-dependent data signal is analyzed to determine the number and location of any intervals of missing data, i.e., gaps in the time series data signal caused by noise in the sensing equipment or the local environment. The quantized time-dependent data signal is also modified by a low pass filter to remove any undesirable high frequency noise components within the signal. A plurality of mathematical models are then individually tested to derive an optimum regression curve for that model, relative to a selected portion of the signal data immediately preceding each previously identified data gap.
    Type: Grant
    Filed: June 28, 1996
    Date of Patent: October 7, 1997
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Francis J. O'Brien, Jr., Chung T. Nguyen, Sherry E. Hammel, Bruce J. Bates, Steven C. Nardone
  • Patent number: 5668778
    Abstract: A method for detecting radiated and reflected acoustic signals from an unwater source, wherein the acoustic signals are present in a random noise environment and form an output therewith. The method includes the steps of operating an entropy-based acoustic receiver to receive the output, calculating the entropy of the received output, and comparing the calculated entropy with a selected entropy threshold value. A substantial difference is indicative of the presence of an acoustic signal from an underwater source. A less than substantial difference is indicative of a lack of presence of an acoustic signal from an underwater source.
    Type: Grant
    Filed: July 9, 1996
    Date of Patent: September 16, 1997
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: Azizul H. Quazi
  • Patent number: 5668777
    Abstract: An integrated torpedo sonar signal processor having an integrated analog-digital conversion component is provided. The torpedo sonar signal processor has four groups of low-pass filtered analog-to-digital converters, each group containing thirteen converters. The output of a group (thirteen converters) is a serial data signal which is outputted to a field programmable gate array which, in turn, converts the combined signal to parallel data word. The parallel data word is outputted to a first digital signal processor which in turn outputs to a second dual-port digital signal processor, the processor providing prefiltering and space-time processing. The output signal is then sent to a beamformer dual-port digital signal processor which has an attached external memory. The beamformer signal is then outputted to a signal processor component containing four dual-port digital signal processors and a common external memory.
    Type: Grant
    Filed: July 8, 1996
    Date of Patent: September 16, 1997
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: Walter T. Schneider
  • Patent number: 5631876
    Abstract: A signal processor for continuous wave (CW) sonars of the type using a doppler filter bank for target detection, in which improved detection capability under reverberation limited conditions and particularly at relatively low doppler values is accomplished by introduction of an adaptive filter providing a notch filter characteristic centered on the mean frequency of the reverberation spectrum and of width and depth continuously automatically adjusted to conform at least approximately to the inverse of the reverberation spectrum. For effecting this adjustment the notch filter is made voltage variable and is enclosed within an automatic notch control (ANC) loop in which the notch control voltage is derived by comparison of signal level on one doppler filter on which appears reverberation plus noise against signal level on another on which appears noise only, to thus derive a control signal providing a measure of reverberation level.
    Type: Grant
    Filed: November 27, 1967
    Date of Patent: May 20, 1997
    Assignee: Lockheed Martin Corporation
    Inventor: James H. Donegan
  • Patent number: 5631877
    Abstract: The narrowband signal revealer comprises a sensor, a baseband generator, an daptive locally optimum processor (ALOP), and a complex signal spectral analyzer. The sensor generates an input signal representative of a tonal signal masked by wideband interference. The baseband generator transforms the input signal into a complex baseband signal. The ALOP processes the complex baseband signal to suppress the interference and generates a complex output signal representative of the tonal signal. The spectral analyzer then analyzes the complex output signal and displays tonal signal power.
    Type: Grant
    Filed: January 11, 1996
    Date of Patent: May 20, 1997
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: James W. Bond
  • Patent number: 5625320
    Abstract: A preamplifier and pre-emphasis network is provided having a differential plifier exhibiting common mode noise rejection. The preamplifier is particularly suited for use with a double-sided sensor element and it includes a double-sided, balanced calibration circuit. First and second variable gain buffers are joined to the differential amplifier for preventing current noise degradation at the differential amplifier inputs. A pre-emphasis network is further provided in conjunction with the variable gain buffers for providing balanced differential gain of the sensor element signal. Further elements of the invention provide for high and low pass filtering, and differential buffering of the output signal.
    Type: Grant
    Filed: October 7, 1994
    Date of Patent: April 29, 1997
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: James D. Hagerty
  • Patent number: 5566134
    Abstract: An algorithm for detecting and tracking dynamically-related sets of unstable passive sonar signals is disclosed. The algorithm detects, enhances, tracks and displays both stable and unstable passive sonar signals, while organizing them into dynamically-related groups. The algorithm is implemented as part of a general purpose digital computer/peripheral system that performs:power spectrum analysis on the segmented time-waveform from the hydrophone,processing of the spectra for detection and enhancement of the signal by the novel algorithms of the present invention and other methods,formatting and displaying of the detected and enhanced signals.The algorithm of the present invention (the ABT, or Automatic Band Tracking algorithm) detects persistent signals having related features by means of correlation and enhances by mathematical integration (or smoothing) of the detected signals.
    Type: Grant
    Filed: May 4, 1972
    Date of Patent: October 15, 1996
    Assignee: Lockheed Martin Corporation
    Inventor: Robert A. Dufault
  • Patent number: 5555534
    Abstract: An ultrasonic receive system includes two receive beamformers. A first receive beamformer is optimized for imaging modes such as B-mode and color Doppler flow imaging, and therefore has high spatial resolution and wide bandwidth, while the accompanying second receive beamformer has a wide dynamic range and is dedicated for use in acquiring spectral Doppler information, which is typically narrowband compared to imaging information. The second receive beamformer achieves the sensitivity and low-noise performance of a dedicated single-channel pencil probe instrument yet it also performs electronic beam steering. Both receive beamformers can operate through a common transducer array, thereby increasing exam efficiency and permitting registration of spectral Doppler information with a B-mode or color Doppler flow image.
    Type: Grant
    Filed: May 2, 1995
    Date of Patent: September 10, 1996
    Assignee: Acuson Corporation
    Inventors: Samuel H. Maslak, Christopher R. Cole, Joseph G. Petrofsky
  • Patent number: 5550792
    Abstract: A method and apparatus is disclosed for making a sliced phased array transducer formed from a single piezoelectric disk which has been bonded to a metal coated support surface. After bonding, the disk and attached metallic coating are cut into a plurality of conductively isolated staves which are then wired into a sequence which allows the array to emit two beams in opposite directions at a depression angle of about 60 degrees. In use, two of the arrays are used adjacent to each other with one emitting beams along the port and starboard sides of the vessel and the other being rotated 90 degrees to emit beams to the force and aft of the vessel, the four beams thereby forming a Janus configuration. Alternatively, the beams could be rotated 45 so that two beams are directed to both the port and starboard sides.
    Type: Grant
    Filed: September 30, 1994
    Date of Patent: August 27, 1996
    Assignee: EDO Western Corp.
    Inventors: F. Anthony Crandall, Kevin V. Jorgensen, Brian L. Grose, Monroe Tyler
  • Patent number: 5541893
    Abstract: Apparatus for processing a broadband signal, 1.2, 2.2, by determining the first and second moments of variation between frequency sub-bands, 1.4, 2.4, of the broadband signal, 1.2, 2.2, in order to either distinguish between man made objects and natural objects or detect shadows comprising splitters, 1.3, 2.3, which comprise analogue or digital filters, for separating the broadband signal into a plurality of frequency sub-band signals, 1.4, 2.4, detectors means, 1.5, 2.5, for processing each of the frequency sub-band signals, 1.4, 2.4, to either extract, identify or enhance a signal within the broadband signal, 1.2, 2.2, and combiners, 1.7, 2.7, for re-combining the processed frequency sub-band signals, 1.4, 2.4, by either summating the frequency sub-band signals, 1.4, 2.4, to produce the first moment of variation or enabling the amount of variation between the processed frequency sub-band signals, 1.4, 2.4, to be analyzed to produce the second moment of variation.
    Type: Grant
    Filed: May 26, 1995
    Date of Patent: July 30, 1996
    Assignee: The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland
    Inventor: Roderick A. Smith
  • Patent number: 5537368
    Abstract: An adaptive statistical filter system for receiving a data stream comprising a series of data values from a sensor associated with successive points in time. Each data value includes a data component representative of the motion of a target and a noise component, with the noise components of data values associated with proximate points in time being correlated. The adaptive statistical filter system includes a prewhitener module, a plurality of statistical filters of different orders and a selection module. The prewhitener module receives the data stream from the sensor and generates a corrected data stream comprising a series of corrected data values each associated with a data value of the data stream, each including a data component and a noise component with the noise components of data values associated with proximate points in time being decorrelated. The plural statistical filters are coupled to receive the corrected data stream in parallel from the prewhitener.
    Type: Grant
    Filed: September 22, 1993
    Date of Patent: July 16, 1996
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Francis J. O'Brien, Jr., Marcus L. Graham, Kai F. Gong, Sherry E. Hammel
  • Patent number: 5526323
    Abstract: In the particular embodiment of the invention described herein, sonar signals in the range from 200-3600 cps. are analyzed by bandshifting selected segments of 100 cps. width to the range 300-400 cps. for analysis, and indications of signals in all of the bands are presented side-by-side on a continuous printer. in addition, the modulation envelope of the detected signal, which contains low frequency modulation components, is demodulated to provide indications of such low frequency components in a target signal.
    Type: Grant
    Filed: September 28, 1965
    Date of Patent: June 11, 1996
    Assignee: General Dynamics Corporation
    Inventor: Robert M. Chapman
  • Patent number: 5511042
    Abstract: An adaptive statistical filter system for receiving a data stream compris a series of data values from a sensor associated with successive points in time. Each data value includes a data component representative of the motion of a target and a noise component, with the noise components of data values associated with proximate points in time being correlated. The adaptive statistical filter system includes a prewhitener, a plurality of statistical filters of different orders, correlation mensuration and decorrelator module and a selector. The prewhitener generates a corrected data stream comprising corrected data values, each including a data component and a time-correlated noise component. The plural statistical filters receive the corrected data stream and generate coefficient values to fit the corrected data stream to a polynomial of corresponding order and fit values representative of the degree of fit of corrected data stream to the polynomial.
    Type: Grant
    Filed: May 25, 1995
    Date of Patent: April 23, 1996
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: Francis J. O'Brien, Jr.
  • Patent number: 5506817
    Abstract: An adaptive statistical filter system for receiving a data stream compris a series of data values from a sensor associated with successive points in time. Each data value includes a data component representative of the motion of a target and a noise component, with the noise components of data values associated with proximate points in time being correlated. The adaptive statistical filter system includes a prewhitener, a plurality of statistical filters of different orders, stochastic decorrelator and a selector. The prewhitener generates a corrected data stream comprising corrected data values, each including a data component and a time-correlated noise component. The plural statistical filters receive the corrected data stream and generate coefficient values to fit the corrected data stream to a polynomial of corresponding order and fit values representative of the degree of fit of corrected data stream to the polynomial.
    Type: Grant
    Filed: May 25, 1995
    Date of Patent: April 9, 1996
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: Francis J. O'Brien, Jr.
  • Patent number: H1526
    Abstract: A hydrophone preamplifier design utilizing hybrid integrated circuits, surface mounted components, multi-layered circuit boards and gain switching. Acoustic signals from a sensor are applied to a hybrid integrated circuit preamplifier whose gain is controlled by a relay activated remotely from a control that allows a predetermined attenuation permitting measurements of high sound pressure levels (low gain) or low ambient noise levels (high gain). The preamplifier in the hybrid integrated circuit provides a gain of 10 (20 dB) and an additional gain of 10 is provided by a low-noise operational amplifier (op amp). A current booster provides the output current drive capability for the preamplifier which is capable of driving large capacitive loads and has protection against both electrical and thermal overloads. Insertion calibration is provided through an ac current signal supplied by an external source, which develops a small voltage signal when supplied to the preamplifier.
    Type: Grant
    Filed: April 21, 1995
    Date of Patent: April 2, 1996
    Assignee: United States of America
    Inventors: Larry E. Ivey, Michael T. McCord
  • Patent number: H1528
    Abstract: A hydrophone preamplifier control unit provides for front panel controls and cable connectors for applying a calibration current and operating voltage to the hydrophone, controlling the level of these voltages, and monitoring the operation of the hydrophone. The control unit assures the continuity of the electrical circuits to a hydrophone through the use of a calibration current applied to the hydrophone through the use of a calibration current applied to the hydrophone through an interconnecting cable.
    Type: Grant
    Filed: February 24, 1995
    Date of Patent: May 7, 1996
    Assignee: United States of America
    Inventors: Michael T. McCord, Larry E. Ivey