Patents by Inventor David Hedley

David Hedley 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: 6813529
    Abstract: An apparatus and method are provided for decoding single-frequency or multi-frequency signals, such as DTMF signals, without the use of analog bandpass filters. The method of the present invention is equally applicable to any decoding of multi-frequency signals. The method is composed of a number of steps. First, an incoming (analog) signal is received and transformed into binary signals (1 or 0) at specific instances of time. The incoming binary signal is compared to a pre-defined expected (binary) signal at each time step. The incoming and expected bit values for each time step are then compared and the comparison result is stored as part of a frequency response table. The comparison values are then summed and, if the summed value exceeds a pre-defined threshold, the incoming and expected signals are declared a match. Otherwise, the signals are declared a mis-match.
    Type: Grant
    Filed: January 19, 2001
    Date of Patent: November 2, 2004
    Assignee: Microchip Technology Incorporated
    Inventor: David Hedley
  • Patent number: 6479722
    Abstract: A process for the production of dimers from an olefinic feedstock containing &agr;-olefins, by contacting the feedstock with a metallocene/aluminoxane catalyst, thereby selectively to dimerize &agr;-olefins in the feedstock by way of a metallocene-catalyzed dimerization reaction. The feedstock is in the form of a Fischer-Tropsch-derived definic feedstock involving a mixture of Fischer-Tropsch-derived hydrocarbons made up of at most 90% by mass of &agr;-olefins, at least 5% by mass of olefins, other than &agr;-olefins, selected from linear internal olefins, branched internal olefins, cyclic olefins, dienes, trienes and mixtures thereof, at least 5% by mass of constituents, other than olefins, selected from paraffins, oxygenated hydrocarbons, aromatic hydrocarbons and mixtures thereof. The metallocene-catalyzed dimerization reaction takes place while the olefins which are dimerized form part of the mixture constituted by the feedstock.
    Type: Grant
    Filed: November 1, 2000
    Date of Patent: November 12, 2002
    Assignee: Sasol Technology (Proprietary) Limited
    Inventors: Hester De Wet, David Hedley Morgan, Alta Ranwell