Patents by Inventor John G. Frost

John G. Frost 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: 4606350
    Abstract: A circuit for measuring the internal impedance of the cell of a heart pacer in order that the remaining life of the cell can be estimated. The test is performed by cutting off all current flow from the cell to the pacer circuitry, the pacer still being powered, however, by the conventional by-pass capacitor. When the cell impedance test is conducted, a test capacitor is placed across the cell and it charges exponentially with a time constant which is a function of the cell impedance. By measuring the time required for the test capacitor potential to reach a reference level, the cell impedance can be ascertained. The measured parameter can be telemetered out of the pacer along with other data in the conventional manner. With a typical lithium iodide cell, the internal impedance of the cell varies from less than 100 ohms when new, to tens of kilohms near the end of the cell life.
    Type: Grant
    Filed: November 28, 1984
    Date of Patent: August 19, 1986
    Assignee: Telectronics N.V.
    Inventor: John G. Frost
  • Patent number: 4509529
    Abstract: The signal sensed on a heart pacer electrode is converted by a delta modulator to a sequence of samples of 0 and 1 bit values. The resulting bit sequence is delayed, and the original bit sequence and its delayed version are continuously subtracted from each other in a clocked up/down counter to derive a count. When the count reaches a threshold value, three different recognition logic circuits are triggered and they then operate for two milliseconds. One circuit recognizes a beat if the count does not drop below another, lower threshold value during the timing interval. A second circuit detects a beat if the count remains above the threshold level for at least 50% of the time during the timing interval. The third circuit detects a beat by operating directly on the delta modulator output bit sequence; it checks whether bits of the value indicative of the triggering event predominate over bits of the opposite value during the timing interval.
    Type: Grant
    Filed: June 30, 1982
    Date of Patent: April 9, 1985
    Assignee: Telectronics Pty. Ltd.
    Inventors: David K. Money, Stephen Swift, Andrew MacLaurin, John G. Frost