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Re: Fast D/A ?

Subject: Re: Fast D/A ?
From: Rob Morley
Date: Sun, 23 Nov 2008 11:32:12 +0000
Newsgroups: uk.comp.homebuilt
On Sat, 22 Nov 2008 23:04:36 +0000
Dave J. <[email protected]> wrote:

> Any ideas anyone? I recognise that this may not be the ideal group
> for a question like this one but it's just happened and this is a
> group I feel comfortable with.
> 
IIRC there are several free programs available to use a sound card as
a 'scope.

As for higher frequencies, the following is just from Google, I don't
claim any expertise in this area.  :-)

//
Is it possible to make a PC-based oscilloscope out of a PCI video
capture card?

No, but sometimes mabie

If your card reads in baseband component video (svideo/RGB), and
processes it using the CPU (if the card processes you'll loose
everything that would happen during h/vsync), then you might get a yes,
for everything else it's a no.
//
http://forums.bit-tech.net/showthread.php?t=95847

so it sounds like it would be possible if you could find a really 
dumb capture card that does all its decoding in software and has open
source drivers:

//
Frame Grabbers.

This class of card is the simplest and is usually the cheapest. There
is no on-board encoding of the analog video; hardware known as a
Digital-Analog Converter (DAC) takes the video and presents it to the
computer in an essentially raw digital form.

...

The most common inexpensive cards available use the Bt848, Bt878 or
CX2388x series of video capture chips; examples are the "Hauppauge
WinTV Go" card and the "AverTV Desktop PVR" card, both of which use the
bttv kernel module.
//
http://www.mythtv.org/docs/mythtv-HOWTO-singlehtml.html



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