Patents Assigned to The United States of America as represented by the National
Security Agency
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Patent number: 6556967Abstract: The present invention is a device for and method of detecting voice activity by receiving a signal; computing the absolute value of the signal; squaring the absolute value; low pass filtering the squared result; computing the mean of the filtered signal; subtracting the mean from the filtered result; padding the mean subtracted result with zeros to form a value that is a power of two if the result is not already a power of two; computing a DFFT of the power of two result; normalizing the DFFT result of the last step; computing a mean of the normalization; computing a variance of the normalization; computing a power ratio of the normalization; classifying the mean, variance and power ratio as speech or non-speech based on how this feature vector compares to similarly constructed feature vectors of known speech and non-speech. The voice activity detector includes an absolute value squarer; a low pass filter; a mean subtractor; a zero padder; a DFFT; a normalizer; and a classifier.Type: GrantFiled: March 12, 1999Date of Patent: April 29, 2003Assignee: The United States of America as represented by the National Security AgencyInventors: Douglas J. Nelson, David C. Smith, Jeffrey L. Townsend
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Patent number: 6541288Abstract: A method of measuring reflectivity of a semiconductor laser facet by first fabricating first and second semiconductor lasers. The reflectance of the facets of the lasers are then determined. The threshold current densities of the lasers are then measured. If the reflectance of the first facet of the first semiconductor laser is modified then setting u=1, x=1, and y=1. If the reflectance of the first facet and the second facet of the first semiconductor laser are modified to the same extent then setting u=1, x=1, and y=0.5. The threshold current density of the first semiconductor laser after reflectivity modification is then measured. The reflectance of the modified first semiconductor laser is then calculated as follows: R1=(u){(R0)Exp[x−(2y[(1/L1)−(1/L2)]L1(J1−J3)/(J1−J2))]}.Type: GrantFiled: January 18, 2002Date of Patent: April 1, 2003Assignee: The United States of America as represented by the National Security AgencyInventor: John L. Fitz
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Patent number: 6538616Abstract: The present invention is an antenna with a cubic core. A first conductor is wound around the core's first axis. A first dielectric layer is placed around the first conductor. A first electrical shield is placed around the first dielectric layer. A second dielectric layer is placed around the first electrical shield. A second conductor is wound around the second dielectric layer in the core's second axis. A second electrical shield is placed around the third dielectric layer. A fourth dielectric layer is placed around the second electrical shield. A third conductor is wound around the fourth dielectric layer in the core's third plane. A fifth dielectric layer is placed around the third conductor. A third electrical shield is placed around the fifth dielectric layer. Each conductor is connected to an amplifier. Each amplifier is connected to an anti-aliasing filter. Each anti-aliasing filter is connected to an analog-to-digital converter.Type: GrantFiled: December 18, 2001Date of Patent: March 25, 2003Assignee: The United States of America as represented by the National Security AgencyInventor: Fernand D. Bedard
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Patent number: 6531414Abstract: A method of forming a native oxide from at least one strain-compensated superlattice of Group III-V semiconductor material, where each at least one superlattice includes two monolayers of a Group III-V semiconductor material and at least two monolayers of an aluminum-bearing Group III-V semiconductor material. The method entails exposing each at least one superlattice to a water-containing environment and a temperature of at least about 425 degrees Celsius to convert at least a portion of said superlattice to a native oxide. The native oxide thus formed is useful in electrical and optoelectrical devices, such as lasers.Type: GrantFiled: May 2, 2000Date of Patent: March 11, 2003Assignee: The United States of America as represented by The National Security AgencyInventors: Frederick G. Johnson, Bikash Koley, Linda M. Wasiczko
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Patent number: 6519362Abstract: The present invention is a method of extracting text from a color image by receiving a color image made up of pixels in any color component system, converting the color image to a grayscale image by performing one to five conversion methods, comparing the grayscale images to a user-definable threshold, and turning the grayscale images into binary images that may be further processed by an optical character reader or a search engine.Type: GrantFiled: February 15, 2000Date of Patent: February 11, 2003Assignee: The United States of America as represented by the National Security AgencyInventor: Adolf Cusmariu
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Patent number: 6498770Abstract: A timer circuit that utilizes the thermal runaway effect, and includes a switch, a resistor, a transistor and a protective device. The temperature of the transistor rises due to a phenomenon known as the thermal runaway effect, which causes the temperature of the transistor to rise while increasing current flow. This will eventually cause the protective device to activate. The time it takes to activate the protective device is predictable for a given transistor, therefore the circuit operates as a timer. In an alternate embodiment, a heat source is used. This heat source rises in temperature as current flows in the circuit. A heat sensor located near the heat source rises in temperature along with the heat source. A comparator compares the temperature from this heat sensor with the temperature of a heat sensor located further from the heat source. When there is a user-definable difference in temperature due to thermal diffusion between the two heat sensors, power to the transistor is disconnected.Type: GrantFiled: September 28, 2000Date of Patent: December 24, 2002Assignee: The United States of America as represented by the National Security AgencyInventors: Craig A. Rockenbauch, James F. Korenz
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Patent number: 6493366Abstract: A vertical cavity surface emitting laser that includes a Group III-V semiconductor material substrate; a first Distributed Bragg Reflector mirror, where the first Distributed Bragg Reflector mirror includes at least seven pairs of layers, where each layer has a different index of refraction, where one of the layers is a Group III-V semiconductor material, and where the other layer is a completely oxidized at least one strain-compensated superlattice of Group III-V semiconductor material, where each at least one strain-compensated superlattice includes at least two monolayers of a Group III-V semiconductor material and at least two monolayers of an aluminum-bearing Group III-V semiconductor material; a first Group III-V semiconductor material layer; a first contact; a selectively oxidized at least one strain-compensated superlattice of Group III-V semiconductor material, where each at least one strain-compensated superlattice of Group III-V semiconductor material includes at least two monolayers of a Group IIIType: GrantFiled: May 2, 2000Date of Patent: December 10, 2002Assignee: The United States of America as represented by the National Security AgencyInventors: Frederick G. Johnson, Bikash Koley, Linda M. Wasiczko
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Patent number: 6391744Abstract: A method of thinning a non-SOI device using an SOI thinning process that includes the steps of receiving an SOI starting wafer, where the SOI starting wafer includes a silicon substrate and an oxide layer thereon; selecting a non-SOI fabrication process for fabricating the non-SOI device; forming a layer of device quality silicon on the oxide layer of the SOI starting wafer to a sufficient thickness and doping profile to realize the non-SOI device; fabricating the non-SOI device in the device quality silicon layer using the non-SOI fabrication process selected; forming a support layer on the device quality silicon layer having the non-SOI device fabricated therein; and thinning the result of the last step using the SOI thinning process.Type: GrantFiled: March 19, 1997Date of Patent: May 21, 2002Assignee: The United States of America as represented by the National Security AgencyInventors: John J. Hudak, Thomas R. Neal, Pramod Chintaman Karulkar
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Patent number: 6385205Abstract: A hardware-only filter system for controlling data packet traffic across a computer network, characterized by the provision of a grid having columns and rows, a grid populating device for introducing into the squares of the grid, respectively, binary numbers that are a function of the comparison between an incoming packet and the column and row headers of the grid. The insertion of the binary numbers into the square of the grid is controlled by an offset positioning device containing predetermined offset instructions. When the squares of any given column are all positive matched values, the filter system is operable to pass the entire approved packet.Type: GrantFiled: February 8, 2000Date of Patent: May 7, 2002Assignee: The United States of America as represented by the National Security AgencyInventor: Jaime A. Romero
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Patent number: 6385543Abstract: The present invention is a method of removing at least one feature from a signal by receiving the signal in the time domain; identifying at least one frequency to be removed; identifying a number of resolution levels to which the signal will be reduced using wavelet transformation; computing at least one wavelet difference coefficient for each resolution level and at least one wavelet average coefficient for the lowest resolution level; creating a projection of each at least one frequency onto the lowest resolution level using Fourier transformation; subtracting the projection from the corresponding at least one wavelet average coefficient; and adding the results of the last step to the at least one wavelet difference coefficient.Type: GrantFiled: May 17, 2000Date of Patent: May 7, 2002Assignee: The United States of America represented by the National Security AgencyInventor: James M. Keiser
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Patent number: 6381568Abstract: Speech transmission method by initializing silence, transmit, and blank-period counters; receiving frame; determining frame is speech; if transmit counter is zero and blank-period counter is less than x then discard frame, increment blank-period counter, and return to second step; if transmit counter is zero, blank-period counter greater than x−1, and frame not speech then discard frame, increment blank-period counter, and return to second step; if transmit counter is zero, blank-period counter greater than x−1, and frame is speech then set transmit counter to one, set blank-period counter to zero, set silence counter to zero, encode frame, transmit encoded frame, and return to second step; if transmit counter is one, frame not speech, and silence counter less than y then encode frame, transmit encoded frame, increment silence counter, and return to second step; if transmit counter is one, frame not speech, and silence counter greater than y+z−2 then set transmit counter to zero, discarType: GrantFiled: May 5, 1999Date of Patent: April 30, 2002Assignee: The United States of America as represented by the National Security AgencyInventors: Lynn Michele Supplee, Richard A. Dean, Mary A Kohler
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Patent number: 6377260Abstract: The present invention is a method of obtaining a time history of a signal without having to integrate information on magnitude versus time and phase versus time by separately displaying sets of real and imaginary components of a signal verses time, including the steps of sampling the signal in time, where each time sample of the signal is described by a real and imaginary component; selecting a size of a display on a screen; determining the real and imaginary components for each time sample of the signal; selecting a user-definable number of samples to be displayed at any one instance; and displaying each time sample according to its real component along the X-axis, the imaginary component along the Y-axis, and the time associated with the time sample along the Z-axis.Type: GrantFiled: January 24, 2000Date of Patent: April 23, 2002Assignee: The United States of America as represented by the National Security AgencyInventor: Richard John Kuehnel
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Patent number: 6331991Abstract: The optical signal produced by a modulated semiconductor laser is passed through a fiber grating optical discriminator to increase the modulation response of the device and decrease the output chirp for transmission through optical fiber. In one embodiment, a simple pulse source comprises a directly modulated single mode semiconductor laser and a fiber Bragg grating filter. A single-mode semiconductor laser, such as, a distributed feed-back laser is driven by the addition of a DC bias current and a sinusoidal current at the desired bit rate. The output of the laser is passed through a low pass or high pass fiber Bragg grating filter with a sharp edge to produce nearly transform limited pulses. Stabilization of a laser apparatus is included.Type: GrantFiled: July 15, 1999Date of Patent: December 18, 2001Assignee: The United States of America as represented by the National Security AgencyInventor: Daniel Mahgerefteh
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Patent number: 6321005Abstract: A device for compensating for dispersion that includes a single-mode optical fiber consisting of a core, and a cladding, where the fiber has five section, a first section of a user-definable length; a second section of a user-definable length that is tapered at a user-definable rate to a user-definable diameter; a third section of a user-definable length and user-definable cutoff wavelength that is of a diameter equal to that which the second section was tapered; a fourth section of a length equal to the length of the second section, where the fourth section is tapered at the same, but opposite, rate of taper as the second section to a diameter equal to the diameter of the first section; a fifth section of a length equal to the length of the first section, and where the fiber has a user-definable cutoff wavelength. In a second embodiment, two spatial-mode converters are included with the fiber. In a third embodiment, a core-block is induced in the fiber.Type: GrantFiled: August 23, 2000Date of Patent: November 20, 2001Assignee: The United States of America as represented by The National Security AgencyInventor: Duane A. Satorius
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Patent number: 6298144Abstract: A device for and method of detecting motion between a reference image and a test image by acquiring the images; aligning the images; dividing the images into blocks; masking certain blocks; differencing corresponding blocks; median filtering the differences; low-pass filtering the outputs of the median filter; generating a normalized histogram for each output of the low-pass filter; generating a model of gaussian noise; calculating the distance between the noise model and each normalized histogram; comparing each distance calculated to a user-definable threshold; and determining if motion has occurred between the images if a certain number of distance calculations are at or above the user-definable threshold. If a scene is to be continuously monitored and no motion occurred between the previous reference image and the previous test image then a new test image is acquired and compared against the previous reference image as described above.Type: GrantFiled: May 20, 1998Date of Patent: October 2, 2001Assignee: The United States of America as represented by the National Security AgencyInventors: Leonard G. Pucker, II, David B. Sofge
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Patent number: 6272141Abstract: A network or interconnect structure utilizes a data flow technique that is based on timing and positioning of messages communicating through the interconnect structure. Switching control is distributed throughout multiple nodes in the structure so that a supervisory controller providing a global control function and complex logic structures are avoided. The interconnect structure operates as a “deflection” or “hot potato” system in which processing and storage overhead at each node is minimized. Elimination of a global controller and buffering at the nodes greatly reduces the amount of control and logic structures in the interconnect structure, simplifying overall control components and network interconnect components and improving speed performance of message communication.Type: GrantFiled: September 14, 1999Date of Patent: August 7, 2001Assignee: The United States of America as represented by the National Security AgencyInventor: Coke S. Reed
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Patent number: 6246348Abstract: The present invention is a device for converting an input signal of various formats to NRZ format in a user-selectable format with automatic self-testing, that includes at least one first channel, where each first channel includes a comparator, an activity detector, an inverter, and a driver circuit, where the comparator is configured for different signal types; at least one second channel, where each second channel includes a transformer, a digitizer, an activity detector, a decoder, a framer, a clock and data recovery circuit, a first driver circuit, and a second driver circuit, having an input connected to the second output of the clock and data recovery circuit, and having an output; at least one third channel, where each third channel includes a transformer, a digitizer, an activity detector, a decoder, a clock and data recovery circuit, a first driver circuit, and a second driver circuit; at least one fourth channel, where each fourth channel includes a transformer, a fanout circuit, a digitizer, an actType: GrantFiled: February 23, 2000Date of Patent: June 12, 2001Assignee: The United States of America as represented by the National Security AgencyInventor: Steven R. Moscatelli
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Patent number: 6243467Abstract: A method of generating and verifying a digital signature by selecting an elliptic curve; selecting a point G; generating x and M; reducing x; generating a base tau expansion, in non-adjacent form, of the reduced x; multiplying G by the expansion; computing h=Hash(M); generating k; reducing k; generating a base tau expansion, in non-adjacent form, of the reduced k; multiplying G by the expansion of k to form K=(Kx,Ky); computing R=(Kx mod q); returning to the step of generating k if R=0, otherwise computing S=(k{circumflex over ( )}−1)(h+xR); returning to the step of generating k if S=0, otherwise transmitting y, q, M, R, and S; receiving y, q, M, R, and S; proceeding with the next step if 0<R<q and 0<S<q, otherwise not verifying the digital signature and stopping; forming h=Hash(M); computing f=((S{circumflex over ( )}−1) mod q), b=(hf mod q), and t=(Rf mod q); reducing b and t; generating a base tau expansion,Type: GrantFiled: July 23, 1998Date of Patent: June 5, 2001Assignee: The United States of America as represented by the National Security AgencyInventors: Robert W. Reiter, Jerome A. Solinas
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Patent number: 6190433Abstract: The present invention is a method of recovering a gate-level netlist from a transistor-level netlist by functionally describing each gate to be recovered using a first transistor model; generating a signature for each gate to be recovered; receiving the transistor-level netlist; selecting a set of connected components from the transistor-level netlist; functionally describing the set of connected components using the first transistor model; generating a signature for the set of connected components; comparing the signature of the set of connected components to the signature of each gate to be recovered; if the signature of the set of connected components matches a signature of a to be recovered then determining if the corresponding functional descriptions match; if a match occurs then functionally describing the set of connected components using a second transistor model; comparing the functional descriptions generated for the set of connected components using the first and second transistor models; identifyiType: GrantFiled: November 10, 1998Date of Patent: February 20, 2001Assignee: The United States of America as represented by the National Security AgencyInventors: W. Mark Van Fleet, Michael R. Dransfield
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Patent number: 6175625Abstract: The machine involves code wheels in cascade or in a maze with random or mixed circuits which operate a printing device to print the cipher conjugate of the letter on an operated key when the keyboard is connected to one end of the code wheel maze, and to print the plain conjugate of the letter in cipher when a key bearing such letter is operated with the keyboard connected to the other end of the code wheel maze. The printer is connected to the end of the code wheel maze opposite the end to which the keyboard is connected in both cases.Type: GrantFiled: December 15, 1944Date of Patent: January 16, 2001Assignee: The United States of America as represented by the National Security AgencyInventors: Laurance F. Safford, Donald W. Seiler