           100 IRE(1/2)

An IRE is a unit used in the
measurement of composite video
signals. Its name is derived from
the initials of the
#YInstitute of Radio Engineers#Y.

A value of 100 IRE was
originally defined to be the
range from black to white in a
video signal.

A value of 0 IRE corresponds to
the zero voltage value during the
blanking period. The sync pulse
is normally 40 IRE below the zero
value, so, peak to peak, an all
white signal should be equal to
140 IRE.



                       #C(cont...)#C
           100 IRE(2/2)

The reason IRE is a relative
measurement (percent) is because
a video signal may be any
amplitude.

This unit is used in the
#YITU-R BT.470#Y which defines
PAL, NTSC and SECAM

You can press #GR#G or #GL#G buttons
to advance in 10 IRE steps in the
selected range.

With button #GA#G you can toggle
the range between #C[0-100]#C and
#C[100-140]#C IRE.