Patents by Inventor Roelof Vreeken

Roelof Vreeken 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).

  • Circuit for synchronizing an oscillator to a pulse train
    Patent number: 4689577
    Abstract: In an arrangement comprising a phase control circuit the phase comparator, when receiving input pulses with which the clock pulses are in phase, will produce an output signal having a pulse frequency which is twice the pulse frequency of the input pulses. The ripple on the control-voltage for the oscillator to be controlled resulting therefrom is compensated for by adding to the output signal of the phase detector a signal which is opposite in phase to the output signal. The result is that only frequency- and phase errors produce a ripple (change) on the output signal.
    Type: Grant
    Filed: May 20, 1985
    Date of Patent: August 25, 1987
    Assignee: U.S. Philips Corporation
    Inventors: Roelof Vreeken, Edmond De Niet, Albert M. A. Rijckaert