20 May
2024
20 May
'24
8:49 p.m.
On May 20, 2024, at 3:40 PM, Adrian Godwin via cctalk
<cctalk(a)classiccmp.org> wrote:
I remember the VT100 interlace setting. Yes, it changed the signal
generated. I don't know if it also changed the characteristics of the
monitor but I would think not.
The Pro also has such a thing in its video card. It doesn't touch the monitor as far
as I can tell. The details may in the video gate array spec (I have that on paper, buried
somewhere); my guess would be that it changes the vertical sync frequency from horizontal
rate / 262 to horizontal rate / 262.5.
It gave slightly higher resolution (the expectation
would be double but the
tube didn't have focus that good) at the cost of a horrible juddering
display. I don't remember it being there on the later VT220.
Yes, that's just how I remember it on the Pro.
The Pro has another display feature: you can set it to 625 lines at 25 Hz (or half that at
50 Hz). The US monitor handles that, somewhat to my surprise, but it's not a pleasant
experience.
paul