Patents Assigned to Telecommunications Research Laboratories
  • Patent number: 5850505
    Abstract: A method for restoring traffic in a network. The network includes plural distinct nodes interconnected by plural distinct spans, each span having working links and spare links. Each node has a digital cross-connect switch for making and breaking connections between adjacent spans forming span pairs at a node. Step 1: For each of at least two possible span failures, (a) find the number of restoration routes available in case of the occurrence of each span failure, (b) determine the resources used by each restoration route, and (c) determine the amount of flow to be restored for each span failure. Step 2: find, in a computer, the amount of flow f.sup.p to be restored along each restoration route that minimizes total unrestored flow for all possible span failures identified in step 1. Step 3: form connections at each digital cross-connect switch in the network along each restoration route before occurrence of one of the possible span failures identified in step 1 to permit the amount of flow f.sup.
    Type: Grant
    Filed: November 1, 1995
    Date of Patent: December 15, 1998
    Assignee: Telecommunications Research Laboratories
    Inventors: Wayne D. Grover, Michael H. MacGregor
  • Patent number: 5848139
    Abstract: Delay-tolerant calls access slack capacity in a telecommunications network under variable pricing controlled by the network so as to permit the network to pick up or stimulate background traffic loads as and when desired to gain revenue from background idle capacity.
    Type: Grant
    Filed: November 19, 1996
    Date of Patent: December 8, 1998
    Assignee: Telecommunications Research Laboratories
    Inventor: Wayne D. Grover
  • Patent number: 5841841
    Abstract: Simultaneous communication of data and voice on a common telephone line are provided between a customer location and a central switching location. At the customer location there may be provided a series of computers each having the LAN interface connected to a common data bus at the customer location with that bus connected to the telephone line. At the central switching station the telephone lines are connected to a central hub device which does not provide a data bus but connects to the Internet. High and low pass filters allow the data from the LAN interface from the voice from a telephone set to be communicated simultaneously on the common line. Equalization and pre distortion are provided to enhance transmission line distances.
    Type: Grant
    Filed: November 17, 1997
    Date of Patent: November 24, 1998
    Assignee: Telecommunications Research Laboratories
    Inventors: David E. Dodds, Gregory J. Erker
  • Patent number: 5839105
    Abstract: There is provided a speaker-independent model generation apparatus and a speech recognition apparatus which require a processing unit to have less memory capacity and which allow its computation time to be reduced, as compared with a conventional counterpart. A single Gaussian HMM is generated with a Baum-Welch training algorithm based on spoken speech data from a plurality of specific speakers. A state having a maximum increase in likelihood as a result of splitting one state in contextual or temporal domains is searched. Then, the state having a maximum increase in likelihood is split in a contextual or temporal domain corresponding to the maximum increase in likelihood. Thereafter, a single Gaussian HMM is generated with the Baum-Welch training algorithm, and these steps are iterated until the states within the single Gaussian HMM can no longer be split or until a predetermined number of splits is reached. Thus, a speaker-independent HMM is generated.
    Type: Grant
    Filed: November 29, 1996
    Date of Patent: November 17, 1998
    Assignee: ATR Interpreting Telecommunications Research Laboratories
    Inventors: Mari Ostendorf, Harald Singer
  • Patent number: 5825257
    Abstract: A Gaussian Minimum Shift Keying modulator that provides direct modulation of a carrier signal, produced by a single microwave high power voltage controlled oscillator. A continuous phase frequency shift keyed modulated signal with a modulation index of 0.5 is produced at the desired output frequency using a full 360 degree linear continuous phase modulator, controlled by a linear baseband signal that is the integral of the binary baseband information signal. This modulated signal is used as the reference signal for a phase locked high power voltage controlled oscillator. The phase locked loop provides frequency tracking and Gaussian spectral shaping to the modulated output signal.
    Type: Grant
    Filed: June 17, 1997
    Date of Patent: October 20, 1998
    Assignee: Telecommunications Research Laboratories
    Inventors: David M. Klymyshyn, Surinder Kumar, Abbas Mohammadi
  • Patent number: 5784032
    Abstract: A compact diversity antenna is presented consisting of two electrically isolated orthogonal loop conductors joined at a midpoint. This midpoint is also electrically attached to a vertical conductor which produces a third mode of operation electrically isolated from the first modes. The two horizontal conductors and the vertical conductor may be constructed to have various relationships with a ground plane of various shapes and sizes. Some of the possible feed arrangements for each of the antennas is presented as well as matching and tuning circuits. All three antenna elements are found to have relatively weak near electric and magnetic fields on the ground plane side of the antenna where the ground plane is small in extent. This feature provides for reduced radiation into the head and neck of the cellular phone user.
    Type: Grant
    Filed: November 1, 1995
    Date of Patent: July 21, 1998
    Assignee: Telecommunications Research Laboratories
    Inventors: Ronald H. Johnston, Laurent Joseph Levesque
  • Patent number: 5754681
    Abstract: In a signal pattern recognition apparatus, a plurality of feature transformation sections respectively transform an inputted signal pattern into vectors in a plurality of feature spaces corresponding respectively to predetermined classes using a predetermined transformation parameter corresponding to each of the classes so as to emphasize a feature of each of the classes, and a plurality of discriminant function sections respectively calculates a value of a discriminant function using a predetermined discriminant function representing a similarity measure of each of the classes for the transformed vectors in the plurality of feature spaces.
    Type: Grant
    Filed: June 22, 1995
    Date of Patent: May 19, 1998
    Assignee: ATR Interpreting Telecommunications Research Laboratories
    Inventors: Hideyuki Watanabe, Tsuyoshi Yamaguchi, Shigeru Katagiri
  • Patent number: 5723176
    Abstract: An apparatus for forming an optical element on the surface of a substrate by ejecting a curable light guide forming liquid from a nozzle onto the substrate and curing the curable light guide forming liquid. A waveguide may be formed by moving the nozzle in a linear pattern over the surface of the substrate during ejection of the liquid from the nozzle. Curing the liquid may include exposing the liquid to ultraviolet radiation, and the radiation may be applied to only a small portion of the liquid. A multilayered waveguide may be formed by ejecting a further light guide forming liquid onto the first and curing it. A core and cladding may be formed simultaneously by ejecting core forming liquid from an inner tube and cladding forming liquid from an annulus about the inner tube. The waveguide may be formed in a groove, and a splitter may be formed by branching a second waveguide from a first, or by laying out two parallel waveguides and connecting them.
    Type: Grant
    Filed: July 8, 1996
    Date of Patent: March 3, 1998
    Assignee: Telecommunications Research Laboratories
    Inventors: Barrie Peter Keyworth, James Neil McMullin
  • Patent number: 5612653
    Abstract: An impedance matched branch connection for local area networks (LANs). A stub or branch connection increases the number of computers that can connect to a LAN. A star connection is formed when several stub lines are connected at the same point. Stub connections introduce an impedance discontinuity in the line and this discontinuity causes signal reflections which interfere with normal data transmission. The impedance discontinuity is avoided by providing a negative impedance device at the star point which makes the impedance at each transmission line appear as though the stub lines were not added.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: March 18, 1997
    Assignee: Telecommunications Research Laboratories
    Inventors: David E. Dodds, Gregory J. Erker
  • Patent number: 5534101
    Abstract: A method of forming an optical element on the surface of a substrate by ejecting a curable light guide forming liquid from a nozzle onto the substrate and curing the curable light guide forming liquid. A waveguide may be formed by moving the nozzle in a linear pattern over the surface of the substrate during ejection of the liquid from the nozzle. Curing the liquid may include exposing the liquid to ultraviolet radiation, and the radiation may be applied to only a small portion of the liquid. A multilayered waveguide may be formed by ejecting a further light guide forming liquid onto the first and curing it. A core and cladding may be formed simultaneously by ejecting core forming liquid from an inner tube and cladding forming liquid from an annulus about the inner tube. The waveguide may be formed in a groove, and a splitter may be formed by branching a second waveguide from a first, or by laying out two parallel waveguides and connecting them.
    Type: Grant
    Filed: March 2, 1994
    Date of Patent: July 9, 1996
    Assignee: Telecommunication Research Laboratories
    Inventors: Barrie P. Keyworth, James N. McMullin
  • Patent number: 5506959
    Abstract: A method of testing a random access memory (RAM) for single V-coupling faults by establishing a first current value for each cell, for each cell and for each of m data backgrounds, generating a data bit corresponding to an element of an (n, V-1)-exhaustive matrix, and for each of m data backgrounds: (1) applying a read write sequence to each cell; and (2) for each background except the mth background, updating the current value of all cells according to the data bits corresponding to that cell; reading each cell of the RAM; and discarding or repairing the RAM if a cell coupling fault is apparent from the series of values read from the cells of the RAM. Data bits are generated by a matrix reconstruction method or a pseudo-random generator using a hashing of the address of the cell to which the data bit is to be applied.
    Type: Grant
    Filed: August 4, 1994
    Date of Patent: April 9, 1996
    Assignee: Telecommunication Research Laboratories
    Inventor: Bruce F. Cockburn
  • Patent number: 5376786
    Abstract: An improved fiber optic delay line filter is disclosed having each fiber optic light path terminate on a corresponding photo detector adapted to convert the received optical signal to a commensurate electrical signal in bi-polar proportion to an electrical bias level provided to the photo detector where the bias level for each photo detector is independently settable and the outputs of all of the photodetectors are summed to produce an output electrical signal that is filtered by the arranged fiber optic delay line transversal filter.
    Type: Grant
    Filed: April 22, 1993
    Date of Patent: December 27, 1994
    Assignee: Telecommunications Research Laboratories
    Inventor: R. Ian MacDonald
  • Patent number: 5291031
    Abstract: An apparatus and electronic circuit for the measurement of fluid levels in containers. The circuit and apparatus constitute an instrument which measures fluid levels by optical means. Only light signals are used near the fluid itself. The instrument thus provides an intrinsically safe method of measuring fluid levels in the presence of explosive or flammable fluids, vapours or gasses, or in containers which must be electrically isolated.
    Type: Grant
    Filed: April 6, 1992
    Date of Patent: March 1, 1994
    Assignee: Telecommunications Research Laboratories
    Inventors: Robert I. MacDonald, George D. Fraser
  • Patent number: 5067126
    Abstract: A DS-3 to 28 VT1.5 SONET Interface Circuit is shown, without using standard intermediate DS-2 and DS-1 Desynchronizer Phase-Lock Loops. The elimination of DS-2 and DS-1 Desynchronizer Phase Lock Loops results in a significant reduction in cost and complexity of SONET interface circuits for the existing asynchronous digital multiplex hierarchy.
    Type: Grant
    Filed: August 4, 1989
    Date of Patent: November 19, 1991
    Assignee: Telecommunications Research Laboratories
    Inventor: Thomas E. Moore