Subject: Re: Just how many of the group are actively running NetBSD on their Vaxen?
To: Nigel Johnson <nw.johnson@ieee.org>
From: Lord Isildur <mrfusion@uranium.vaxpower.org>
List: port-vax
Date: 10/25/2002 16:53:35
the AAV11 i have claims in the documentation to be able to handle 
multiple 30 KHz channels at once.. definitely good enough for nice audio. 
maybe it's a different board. the VAXlab stuff is three boards i think.. 

isildur

On Fri, 25 Oct 2002, Nigel Johnson wrote:

> I hate to disappoint you, but it won't do anything like the acquisition 
> time for audio.  Isolated in this context means that you can read 
> millivolts on top of a high voltage common mode waveform. The a/d is 
> connected via a flying capacitor which charges off the signal and is then 
> flipped over to the a/d using a reed relay!    I have been thinking about 
> monitoring the 117 volts in my building and graphing it to prove to the 
> power company that it is off-spec, hence the need for the driver.
> 
> These interfaces were pretty rare, I got this in an auction at the Canadian 
> Data Translation disti when they got out of the DEC business. It listed for 
> about $2000 US I htink.
> 
> As far as the MP3s go, some of my students did this with a 2MHz Motorola 
> 68HC11 so it should be possible with a VAX.
> 
> regards
> Nigel Johnson
> 
> 
> At 11:49 02-10-25 -0700, Brian Chase wrote:
> >On Fri, 25 Oct 2002, Nigel Johnson wrote:
> >
> > > btw, I am happily chugging along on with NetBSD on my MicroVax IIs.  One of
> > > them has a Data Translation DT2765 millivolt isolated a/d that I am dying
> > > to use to measure dome kind of power line stuff, but anybody who suggests
> > > an experiment also has to come up with a driver!
> >
> >Oooh.  One project I always thought would be interesting is using A/D
> >and D/A Qbus modules to build a sound card for a VAX.  I doubt a
> >MicroVAX-II would have the VUPs to decode mp3s on the fly, but I'd
> >imagine it'd be fine for low-fidelity uncompressed audio.  I'm sure some
> >of the newer VAX 4000 series would be well suited for the task.
> >
> >The major obstacle being the scarcity of such modules.  I only know of
> >their existence from Megan Gentry's _Field Guide to Qbus and Unibus
> >Modules_; I've never seen them "in the wild."
> >
> >-brian.
> 
>