Patents by Inventor Daniel Perrein

Daniel Perrein 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).

  • Low-frequency alternating current signal detector, in particular for central office line interface circuits
    Patent number: 5218635
    Abstract: A low-frequency alternating current signal detector for recognizing tone signals in a central office line interface circuit connecting a private telephone installation to an analog telephone network subscriber line. The low-frequency alternating current signal detector includes an amplifier (1) connected to the input of a bandpass filter (2) and to the input of a first rectifier-filter (3), a second rectifier-filter (4) and a threshold presence detector (5) connected to the output of the bandpass filter (2). The output of the threshold presence detector (5) selectively enables comparison by a comparator (6) of the bandpass filter input and output signals and signalling of the presence of an alternating current signal.
    Type: Grant
    Filed: June 19, 1990
    Date of Patent: June 8, 1993
    Assignee: Alcatel Business Systems
    Inventors: Andre Bonvallet, Robert Girard, Daniel Perrein