Patents Assigned to Ese Limited
  • Patent number: 4538284
    Abstract: Locations of a desired number of signal points for a double side band-quadrature carrier modulation system occupy the inner intersections of a multiplicity of concentric rings with a triangular grid. The signal point locations of the desired number on the outer partially occupied ring are provided with additional signal points at positions selected to provide that the centroid of the set of locations is at the center of the rings.
    Type: Grant
    Filed: February 25, 1982
    Date of Patent: August 27, 1985
    Assignee: ESE Limited
    Inventors: Gordon R. Lang, George D. Forney, Jr., Shahid Qureshi, Fred M. Longstaff, Chi H. Lee
  • Patent number: 4514855
    Abstract: A sinusoidal component of phase jitter in a communications channel is reduced by apparatus including means providing an oscillator signal at the receiver and modifying the received signal phase in accord therewith. Decision means determine the probable transmitted signal and the signals at the input and output of the decision means are compared to determine the residual phase jitter. The residual phase jitter is compared with a suitably delayed oscillator signal and the results of the comparison are used to alter the modification (by the oscillator signal) of the received signal to further reduce the phase jitter. Preferably the results of the comparison are also used to reduce the frequency difference between the oscillator signal and the phase jitter.
    Type: Grant
    Filed: August 2, 1983
    Date of Patent: April 30, 1985
    Assignee: Ese Limited
    Inventors: Gordon R. Lang, Fred M. Longstaff, Chi H. Lee