Amplifier Patents (Class 381/28)
  • Patent number: 4409436
    Abstract: An AM stereophonic receiver including a stereophonic pilot signal eliminating circuit which substantially completely eliminates a pilot signal in an input stage of a matrix detector. A received AM stereophonic signal, of the type in which the carrier signal is phase-modulated with a sub-signal and amplitude modulated by a main signal, is coupled to a main signal detector and a sub-signal detector. The output of the sub-signal detector is coupled through a band amplifier which produces as an output a signal corresponding to the pilot signal contained in the stereophonic signal. The outputs of the sub-signal detector and main signal detector are coupled to inputs of adder/subtractor circuit in a matrix detector while the output of the band amplifier is also coupled thereto in a phase so as to cancel the pilot signal contained in the output of the sub-signal detector.
    Type: Grant
    Filed: June 17, 1981
    Date of Patent: October 11, 1983
    Assignee: Pioneer Electronic Corporation
    Inventors: Tatsuo Numata, Akira Nishioka, Hitoshi Hirata