2 Oct
2008
2 Oct
'08
1:33 p.m.
--- On Thu, 10/2/08, Roy J. Tellason <rtellason at verizon.net> wrote:
From: Roy J. Tellason <rtellason at verizon.net>
Subject: Re: Unusual software carriers. (Was :Vinyl Data- Classic Computers )
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>
Date: Thursday, October 2, 2008, 10:23 AM
On Thursday 02 October 2008 05:27, Gordon J. C. Pearce MM3YEQ wrote:
Maybe my grasp of current and recent signal processing techniques is a little
too tenouous. My recollection of vertical sync is the composite sync pulses
fed into an integrator which put out a fairly rounded waveform, giving
a "start of sync" point that was fairly ambiguous. Maybe I oughta
study up
on that there digital stuff. :-)
An LM1881 sync separator chip and a counter (or PIC type chip)
is all that you need to select a line, or group of lines.
Bob
On Thu, 2008-10-02 at 00:02 -0400, Roy J. Tellason
wrote:
> I've also been curious for some time as to how one could
"pick
off" a
> specific scan line to get at whatever data was in
there, so if that
> circuit is online anyplace I'd be interested in taking a look at
it,
even if
it's not precisely the same thing.
Detect vsync then count hsync pulses. Or, if you can make it accurate
and stable enough, a monostable.