                   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 and #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.