The composite analogue television signal’s amplitude can be described in volts or IRE units with 140 IRE representing a full amplitude composite analogue signal. The 0 IRE point is at blanking level, with sync tip at –40 IRE and white extending to +100 IRE In the studio, the composite analogue video signal is typically 1 volt in amplitude.

Thus in the studio, 1 IRE is equal to 1/140 of a volt or 7.14 mV. IRE stands for Institute of Radio Engineers, the organisation which defined the unit.