Patents Assigned to USA Digital Radio, Inc.
  • Patent number: 6128350
    Abstract: This invention provides a method for reducing peak to average power ratio in a radio frequency signal. The method comprises the steps of modulating a plurality of sub-carriers with a plurality of data symbol vectors to produce a first modulated signal; limiting the magnitude of the first modulated signal to produce a first limited modulated signal; demodulating the first limited modulated signal to recover the constellation points; predistorting the data symbol vectors to provide a minimum magnitude for in-phase and quadrature components thereof to produce predistorted data symbol vectors; modulating the plurality of carriers with the predistorted data symbol vectors to produce a second modulated signal; limiting the magnitude the second modulated signal to produce a second limited modulated signal; and reducing intermodulation products in the second limited modulated signal. Transmitters that perform the method are also included.
    Type: Grant
    Filed: August 24, 1999
    Date of Patent: October 3, 2000
    Assignee: USA Digital Radio, Inc.
    Inventors: Anjali Shastri, Brian William Kroeger
  • Patent number: 6128334
    Abstract: The present invention provides for a receiver addressable AM compatible digital broadcast system and method. The digital broadcast signal includes a plurality of digitally modulated signals and an analog signal. A transmitter useable within the system includes a data combiner for generating an aggregate digital data signal, and a waveform generator for forming the digital broadcast signal. A receiver useable within the system comprises a waveform detector for separating the signals and a data parser for separating the digitally modulated signals. The present invention further provides for a method of selectively transmitting data via a digital broadcast signal. The method includes forming the digital broadcast signal from an analog signal and a plurality of digitally modulated signals, transmitting and receiving the digital broadcast signal.
    Type: Grant
    Filed: February 21, 1997
    Date of Patent: October 3, 2000
    Assignee: USA Digital Radio, Inc.
    Inventors: Mark J. Dapper, Barry W. Carlin, Michael J. Geile
  • Patent number: 6108810
    Abstract: A broadcasting method encodes program material using convolutional codes having non-puncturable bits and puncturable bits and modulates orthogonal frequency division multiplexed carrier signals with the convolutional codes. The non-puncturable bits are carried by a first group of the carriers and the puncturable bits are carried by a second group of the carriers, where the first group of carrier signals is less susceptible to interference than the second group of carrier signals. The carrier signals are then broadcast to receivers which determine if the carriers in the second group have been corrupted and erase puncturable bits carried by any of the carriers which have been determined to be corrupted. This produces punctured codes which are subsequently decoded to recover the program material.
    Type: Grant
    Filed: March 27, 1998
    Date of Patent: August 22, 2000
    Assignee: USA Digital Radio, Inc.
    Inventors: Brian William Kroeger, Roy Ronald Stehlik, Denise Maureen Cammarata