| 1. an assembly, obtained by frequency division multiplexing, of 15 supergroups in adjacent positions in a frequency band of specified width, with guard bands between adjacent supergroups
2. a frequency band of standardized width, 3 716 kHz, in a multichannel carrier system and occupying one of a number of specified positions in the spectrum
Note 1 – "15-supergroup assembly" is the only term in use by the CCITT.
Note 2 – The French word "hypergroupe" or the English word "hypergroup" is sometimes used for a supergroup assembly different from that standardized by CCITT. Accordingly, this term should be qualified by the number of super-groups used in each application.
Note 3 – A 15-supergroup assembly is normally an assembly of 900 FDM telephone channels.
Note 4 – Signals, other than those derived from an assembly of supergroups but having specified characteristics, may occupy the whole or a part of a frequency band assigned to a 15-supergroup assembly.