Page "Dbx (noise reduction)" Paragraph 22

dbx-TV is included in multichannel television sound ( MTS ), the U. S. standard for stereo analog television transmission.

Every TV device that decoded MTS originally required the payment of royalties, first to dbx, Inc., then to THAT Corporation which was spun off from dbx in 1989 and acquired its MTS patents in 1994 ; however, those patents expired worldwide in 2004.