Patents by Inventor Christopher P. Ash

Christopher P. Ash has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4347615
    Abstract: The presence of a d.c. offset in the input signal to an adaptive equalizer for a high speed modem must be removed before a valid signal enters the equalizer if the "coefficient up-date" algorithm for the equalizer is not to be confused. Normally the d.c compensation is achieved using adjust-on-test resistors or potentiometers which provide for in life adjustments to compensate for ageing drift. The submission envisages the use of an additional adaptive equalizer tap-stage connected to a fixed voltage source. This voltage is multiplied by the additional tap-stage multiplier and summed with the outputs of the other tap-stages in the equalizers accumulator. The error produced from the equalizer decision circuit is correlated with the fixed voltage in the additional tap-stage correlator the output of which controls the gain of the additional tap-stage multiplier thereby compensating for the original d.c. offset of the output of the equalizer accumulator.
    Type: Grant
    Filed: September 16, 1980
    Date of Patent: August 31, 1982
    Assignee: Plessey Overseas Limited
    Inventor: Christopher P. Ash