Patents by Inventor Rolf Erik Ledfelt

Rolf Erik Ledfelt 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).

  • Method and apparatus for real time clock frequency error correction
    Patent number: 6304517
    Abstract: A real time clock, suitable for use in mobile units in a radiocommunication system, is calibrated during production, and corrects for timing inaccuracies during normal operation. As a result, the accuracy of the real time clock's crystal oscillator is increased economically and efficiently. Frequency error correction is performed by periodically adjusting the frequency of the real time clock by a fixed amount once for every interval of time defined by an adjustment value. The adjustment value is determined by a calibration procedure performed during manufacture of the mobile unit.
    Type: Grant
    Filed: June 18, 1999
    Date of Patent: October 16, 2001
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Rolf Erik Ledfelt, Anders Wilhelm Östsjö