Source : Free On-Line Dictionary of Computing

Spectral Band Replication
     
         (SBR) Guessing the nontransmitted higher
        frequency range of a compressed audio file by some helper bits
        (transmiited with the stream) and the transmitted base band.
        SBR allows a restoration (not reconstruction) of the upper
        frequency range without lots of bits.  It was developed by
        {Coding Technology (http://www.codingtechnolgy.com/)}, and is
        useful for medium and high quality coding at low and medium
        data rates.  It is used by {Digital Radio Mondiale} and {MP3
        Pro}.
     
        (2001-12-22)