Patents by Inventor Sture Risberg

Sture Risberg 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).

  • Debugging arrangement
    Patent number: 3939420
    Abstract: Method and apparatus for detecting the presence of a surreptitiously placed radio transmitter or bug. An audio tone signal is transmitted within the confined space containing the bug, and the tone signal has a predetermined frequency and a predetermined amplitude. The tone signal energizes the microphone of the bug, causing it to transmit a radio frequency signal which is modulated according to the tone signal. The radio frequency is then demodulated and the resulting demodulated signal is applied to a narrow pass band filter which is tuned to the audio tone signal. The output of the filter is sensed to determine the presence of the bug.
    Type: Grant
    Filed: January 15, 1974
    Date of Patent: February 17, 1976
    Assignee: Sture Risberg
    Inventors: Sture Risberg, Alf Lindgren, Kjell Rixon, Rickard Wallden, Bengt Brundin