>There certainly are video transformers.  We use them occasionally
>at work when we need to DC isolate a video signal.  It is just a
>toroidial transformer carefully wound to give a good frequency
>responce from about 30Hz to 5MHz.  The DC component is lost but I
>have never noticed that to make a visable difference in the picture.
>I think modern monitors di their own level shifting.  I will try
>to find out who makes them tomorrow.

OK it may be that the expectation is that the monitor will do the DC restore
function anyway, and hence there is no attempt to do it with the
transformer.

IIRC the DC restoration is done by clamping the signal to ground during the
sync pulse, so the worst case is that the transformer has to maintain a
reasonably constant level signal for one line period. My TV & video theory
is getting pretty rusty, but that is how I remember it.

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