13 Jun
1997
13 Jun
'97
5:05 a.m.
In my previous message I wrote (re: meanings of video signals),
The other two signals are the quadrature components of
chrominance.
They are derived from Y by subtracting red and blue, and are normally
called U and V (in some order).
The colour telly receives U and V phase modulated onto a subcarrier (I
think). The hue control on American tellies sets the baseline against
which phase is measured here. (In Europe, the PAL system reverses the
phase each line, so any hue errors should cancel out)
Before someone like Tony jumps down my throat, U and V are _amplitude_
modulated onto the subcarrier, in quadrature with one another. Thus the
phase of the subcarrier gives the hue, and its amplitude the saturation.
I hope you are not any more confused than before :-)
Philip.