Patents Assigned to National Communications Research Center, Inc.
  • Patent number: 4679239
    Abstract: In a system for processing stereo signals prior to application to an AM stereo channel information, the signals prior to broadcasting left channel and right channel automatic gain controllers are specially (L+R) gain controlled to maintain monaural loudness and are then followed by a low and high frequency equalizer and filter network. The system next transforms the audio into (L+R) and (L-R) signals and uses a multiband (L+R) and (L-R) peak limiting and clipping system with a variable gain (L-R) "stereo enhancement" amplifier located in the (L-R) path. The (L+R) and (L-R) audio is then applied to final peak clipping bandwidth filters. Finally, the (L+R) and (L-R) audio is transformed back into left and right audio which undergo left and right negative AGC'ing and peak clipping for decoding compatibility.
    Type: Grant
    Filed: August 22, 1984
    Date of Patent: July 7, 1987
    Assignee: National Communications Research Center, Inc.
    Inventor: Ronald R. Jones