Patents by Inventor Ruth Umstattd

Ruth Umstattd 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: 5511236
    Abstract: A radio frequency (RF) transceiver for modulating and demodulating RF signals with a direct modulation transmitter and a dual intermediate frequency (IF) receiver, respectively, includes a local oscillator, three frequency converters, a demodulator, a carrier generator, a modulator, a controller and two signal switches. The local oscillator (e.g. phase lock loop PLL!) provides a first local oscillator (LO) signal. One frequency converter (e.g. mixer) frequency converts an incoming modulated RF signal with the first LO signal to provide a first modulated IF signal. A second frequency converter frequency converts the first modulated IF signal with a second LO signal to provide a second modulated IF signal. The demodulator also receives the second LO signal and demodulates therewith the second modulated IF signal. The carrier generator (e.g. voltage-controlled oscillator VCO!) receives a transmitter control signal and in accordance therewith generates a transmitter carrier signal.
    Type: Grant
    Filed: August 17, 1994
    Date of Patent: April 23, 1996
    Assignee: National Semiconductor Corporation
    Inventors: Ruth Umstattd, Benny Madsen