Patents by Inventor John Y. Ma

John Y. Ma 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).

  • Patent number: 3965427
    Abstract: A VHF television tuner system has four tunable circuits each including an abrupt junction varactor diode having a predictable capacitance-tuning voltage characteristic. The VHF frequency spectrum is divided into Lo and Hi bands encompassing television channels 2-6 and 7-13, respectively. A pair of voltage divider networks comprising precisely trimmed resistive material on a ceramic substrate provide tuning voltage terminals corresponding to the VHF television channels. The end terminals of each divider network are coupled to adjustable potentiometers for setting the tuning voltage at each extreme of the voltage divider. A substrate mounted switch accesses the tuning voltage points, supplies bandswitching voltages and provides AFC defeat between channels.
    Type: Grant
    Filed: September 3, 1974
    Date of Patent: June 22, 1976
    Assignee: Zenith Radio Corporation
    Inventor: John Y. Ma
  • Patent number: 3962643
    Abstract: A VHF television tuner has four tunable circuits each including an abrupt junction varacto diode having a predictable capacitance tuning voltage characteristic. The VHF frequency spectrum is divided into Lo and Hi bands encompassing television channels 2-14 6 and 7-14 13, respectively. A pair of voltage divider networks comprising precisely trimmed resistive material on a ceramic substrate provide tuning voltage terminals corresponding to the VHF television channels. The end terminals of each divider network are coupled to adjustable potentiometers for setting the tuning voltage at each extreme of the voltage divider. A substrate mounted switch accesses the tuning voltage poins, supplies bandswitching voltages and provides AFC defeat between channels.
    Type: Grant
    Filed: August 5, 1974
    Date of Patent: June 8, 1976
    Assignee: Zenith Radio Corporation
    Inventor: John Y. Ma