IEC 60489-4 Ed. 2.0 b:1991

Covers the definitions, the conditions and the methods of measurement used to ascertain the performance of transmitters having audio-frequency bandwidths generally not exceeding 10 kHz for the transmission of voice and other types of signals, using single-sideband amplitude modulation with full, reduced or suppressed carrier. This standard is intended to be used in conjunction with IEC 60489-1.