[vcf-midatlantic] Open Hardware DSO - 100 MHz/250 Msa/sec - haasoscope

David Gesswein djg at pdp8online.com
Sun Nov 19 17:17:50 EST 2017


On Fri, Nov 17, 2017 at 11:24:03PM -0500, J. Alexander Jacocks via vcf-midatlantic wrote:
> There's a newish project on Crowdsuppy that I thought the group might find
> interesting:
> 
> https://www.crowdsupply.com/andy-haas/haasoscope
> 
> ...
> What does anyone think?
> 
It all depends on that you want to do with it. This is written assuming you
are troublshooting old computers.

You need sufficient bandwidth
to view your signal of intrest and sufficient sample rate to make it look
reasonable. Sampling twice the frequency of a sine wave captures the
information but it doesn't look like one.  There are ways to help the display
some with signal processing though I don't think it does that.

Couple pages discussing
http://www.ni.com/white-paper/4333/en/]
https://www.tek.com/document/online/primer/xyzs-scopes/ch3/evaluating-oscilloscopes

I think the sample rate will be the bigest limitation. You will need to
see the characteristing of signals you will want to look at.

For troubleshooting old equipment the degredation of the signal edges
is normally not as big an issue. The faults are normally not that subtle
but I have run across glitches on signals causing trouble that the low sample
rate can hide. 

The +-5V and +- 500 mV is somewhat limiting but ok for looking at normal
TTL signals. For checking ripple on power supplies or analog work may not
be.

Its onboard display option doesn't seem to have sufficient size or
resolution to be useful so I think you will always need some sort of
computer to use it.

Being able to grow to more channels is interesting though four is useually
enough. I have a 2 channel Rigol and four would be nice at times.

I didn't see enough to evaluate how the software is. Like always poor
software can make anything a pain to use. It says it supports
various triggering without giving specifics.

A reasonable update rate is needed for seeing intermittent problems. I
would get the high speed readout. Its unclear how many waveforms per second
that gives you. 




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