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Re: gEDA-user: zview/ngscope



On 4/17/2011 5:00 PM, Kai-Martin Knaak wrote:
rickman wrote:

When I had the need for an interactive waveform viewer that could
also be driven by an application, I had good success with
     xmgrace http://plasma-gate.weizmann.ac.il/Grace/
It is fully scriptable and can produce publication quality plots,
too.
Would any of these be suitable for a real time update of an o'scope
display?
This is what I meant by the preceding comment: There is an api to
xmgrace that allows any application written in C to feed values to
the GUI and make it update the graphs. So the GUI can show the data
while they pour in. The user still has full GUI control over zoom,
pan and the various aspects of graph scaling. Graphs can be linear,
log scale, rectangular, or polar. Data points can be all kinds of
shapes, with or without error margins. No 3D-imaging, though.

Be aware, that there is a down side: The project has grind to a
virtual stand still since a few years now. The proposed, complete
rewrite that would be grace6 looks like it will never be finished.
By "suitable" I meant suitable in all ways. I can only assume that this code would run fast enough to work well. But the idea sounds right. Can it display analog data as well as logic data? What about the others?

If the code is not going to be available, I guess that disqualifies it unless I want to pick it up and run with it.

I'm just batting around some ideas and would like to find some
software to base an o'scope UI on.
You mean some kind of code re-use?
As opposed to code disuse?  I'm not sure what you mean.

I have been looking for a good commercial mixed mode oscilloscope/logic analyzer and have not found one that has a fast analog front end (meaning ~300 MHz bandwidth), at least 16 bits of digital input and is well under a kilobuck (USD). Most of what I've found are not as functional as I would like or are the same price as a self contained unit or both. Agilent has one but I think they are asking around $2,000 and it has some short comings that I bet their stand alone units don't have. The low cost units all seem to fall very short in the analog input department. I guess I never realized that an oscope analog front end is expensive to build. I figured the price had more to do with the marketing, development and other costs. The small companies don't have many of those costs and I figured they could produce something fairly good at a fraction of the price. They seem to provide up to around 100 MHz bandwidth ok for a few hundred USD, but faster than that and the price jumps up really fast. Maybe it is a marketing issue and there just aren't enough sales of the faster units to amortize the costs.

All that aside, I was looking at some of the home brew oscopes and there are more than one project that has potential. I was thinking of piggybacking off of what ever I could find to see what could be produced. The software seems to be one of the weak points and likely one of the most important points at the same time. A poor UI will make a great hardware design pretty worthless, so it is just as important.

Rick


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