a) A linear scale for measuring the relative amplitudes of the various components of a television signal. Reference white is assigned a value of 100, blanking a value of 0. b) The values for NTSC composite and for SMPTE 240M are shown in the following table. One IRE unit corresponds to 7-1/7 mV in CCIR System M/NTSC and to 7.0 mV in all other systems. Measurement procedure developed by the Institute of Radio Engineers, the predecessor to the IEEE.