10 Jan
2008
10 Jan
'08
5:12 a.m.
On Wednesday 09 January 2008 22:29, Mark wrote:
(Snip)
The monochrome video signal is output on a phono/RCA
socket. Inside the
monitor, a coaxial cable goes from that to the PCB at the end of the
tube.
I need to determine the video signal level. Apparently VGA uses 0.7V
p-p, so I might need to add a resistor in-line to reduce the voltage if
it's any higher.
Or more properly a voltage divider.
Unfortunately I don't have access to an
oscilloscope.
Too bad, as the peak-to-peak amplitude of the signal is really what you'd
need to know here.
Could I just arrange for a full-screen white image to
be shown, measure
the voltage using a normal DC multimeter, and multiply up the value
shown to account for the proportion of each scanline corresponding to
sync/flyback?
Not likely.
Once that issue is solved, I should be able to connect
the video signal
to the green signal pin of a VGA monitor and get a green picture. In
order to get a grey-scale picture, can I simply connect the video signal
via resistors to each of the R, G and B pins on the monitor connector?
If so, what resistor values would be needed? If not, I guess I could use
or build a 1-to-3 splitter/amplifier circuit, then connect the 3 outputs
of that to the R, G and B lines.
A VGA monitor is (in most cases) still going to be looking for sync signals on
separate pins. And you're starting out with composite video? This isn't a
project *I* would care to tackle, and I am way ahead of you when it comes to
equipment and background with this stuff.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
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Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin