Patents by Inventor Kelly L. Hirsch

Kelly L. Hirsch 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).

  • Damping decoupled oscillator using a high impedance crystal
    Patent number: 4810922
    Abstract: A crystal controlled oscillator in which changes in damping are compensated and a method for decoupling the output signal of such an oscillator from damping changes. The damping decoupled oscillator includes a quartz crystal (10), which produces a periodic signal, connected in series with a variable gain amplifier (18) and a variable phase shift circuit (22). Feedback from the output of the variable phase shift circuit is provided to sustain oscillation of the crystal. Unity gain in the loop is maintained by adjusting the gain of the variable gain amplifier in accordance with the DC value of the output signal, provided by a precision rectifier (34). As the DC value of the output signal changes due to changes in damping or energy loss of the crystal, an absolute value circuit (38) responds by providing a phase control signal for adjusting the phase of the periodic signal to compensate for changes in damping.
    Type: Grant
    Filed: January 19, 1988
    Date of Patent: March 7, 1989
    Assignee: Sundstrand Data Control, Inc.
    Inventor: Kelly L. Hirsch