IRE (INSTITUTE OF RADIO ENGINEERS)

1 Volt Peak - Peak Video is divided up into 140 IRE units. This is done to make numbers for luminance levels easier to communicate. The amplitude of the video signal from blanking (zero volts) to peak white is 0.714286 volts or 100 IRE units. Synchronization signals extend from blanking to - 0.285714 volts or - 40 IRE units. Picture Black Level: 7.5 IRE (above zero volts) Picture White Level: 100.0 IRE (above zero volts) Blanking Level : 0.0 IRE (zero volt level) Burst Pedestal : 0.0 IRE (zero volt level) Synchronization :- 40.0 IRE (below zero volts) Black was raised above 0 IRE in the early days of color television to get around some transmitter problems. The practice has been with us ever since. The SMPTE component video system does use the IRE system to define video levels. It is based on a 700 mVolt system rather than the 714 mVolt composite video.