Patents by Inventor Maurice E. Marchand

Maurice E. Marchand 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).

  • Ciphering device improving the secrecy of the encoded replies of a secondary radar
    Patent number: 4145690
    Abstract: A secondary radar system in which the transponder and central station possess for enciphering and deciphering complementary dispersive filters having expansion/compression factors of .theta..DELTA.F.sub.1, where .DELTA.F.sub.1 = 1/.DELTA..mu. is a measure of the spectral width of each reply pulse having a temporal width of .mu., .theta. being at least s .mu./.DELTA..mu., such that at least two adjacent pulses spaced s apart in the initial reply train are completely overlapped in the expanded reply.The application to secondary radar systems, especially of the IFF type, in order to improve considerably the secrecy of the link between an airborne transponder and the ground station.
    Type: Grant
    Filed: August 8, 1977
    Date of Patent: March 20, 1979
    Assignee: Le Materiel Telephonique
    Inventors: Christian H. Petitjean, Maurice E. Marchand, Marcel Denis