Newsgroups: sci.electronics.misc
Subject: Re: Linux PC as oscilloscope
References:  <[email protected]> 
DarkMatter  writes:

> On Sun, 10 Aug 2003 13:15:48 GMT, Blake  Gave
> us:
> 
> >
> >400 bucks, 100MHz scope for Linux:
> >http://www.etcsk.com/linux/
> 
> 
>   It isn't just software.  It requires an EPP port.
> 
>   That means that they have a device that you hook up to get the data.
> 
>   100MHz and parallel ports don't seem to mix, to me.  The device must
> merely send a low resolution data stream to the scope, giving the
> observer a dithered view of the real data.
> 
>   Not what I would call high resolve.  I'd bet that a lot of
> information on a 100MHz signal would be unviewable to the user of the
> product.

The oscilloscope products that connect to PC through a slow port 
(serial, parallel etc.) and can sample at high rates are generally 
implemeted in the following way:
The device has a buffer memory in it. When the device starts sampling 
(manual start or automatic trigger), it then samples it's memory full 
at the given sample rare. After the data is sampled to memory it  
is stransferred to the PC. And the process can start all over. 


-- 
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at 
http://www.epanorama.net/