Anyone using a Welec W20xxA DSO?

As far as I can see, Wittig is selling significant numbers of their very cheap 1Gs/s 200MHz DSOs via ebay (e.g. 190302544569).

As I am familiar with most of the issues regarding this scope, I would like to know, wether users have upgraded from the original, pretty - let's say - improvable firmware to the much better OpenSource version.

Regards, Falk

Reply to
Falk Willberg
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Made in England, and it went for 350 Euros? Wow! Do these things really work?

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Regards, Joerg

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Reply to
Joerg

For those playing along at home:

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and the hardware:
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Pretty obvious they were not using a true 1GS/s converter.

the front end schematic:

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Dave.

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Reply to
David L. Jones

Eine interessante Antwort ist hier:

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At the bottom of quite a lot of information is this note from a purchaser:

"Welec, is the same company previously called Wittig Electronics that went bankrupt. I purchased a W2012 (note no "A") that looks identical. it was a POS. I use PayPal for eBay purchases, and was able to get refund. Perhaps you can too. These guys are very shady. I'm not sure how they get such high ratings on eBay, they must be gaming the system. I ended up buying a used Tek DSO on eBay, and I'm satisfied."

Jon

Reply to
Jon Kirwan

Yes, I saw that. But Falk participates a lot in the German NG and does real electronics, so it must work for him to some extent. If you can get these for 350 Euros that almost looks like a liquidation sale.

Sometimes it's ok to live with certain shortcomings. Like the remote control SW for my Instek which is unfortunately .NET-based and crashes a lot. Not nice but still allows me to not have to switch between 3x glasses for SMT and 1.5x to look at the scope. However, from links like te one above it appears that the internal software of that W2012 must be really horrid.

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Joerg

A lot of people who buy these really cheap no-name scopes typically don't know anything about scopes or how they should perform, so as long as they get a waveform on the screen they are happy with their purchase and hence leave positive feedback.

I love the quote from here:

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" Meanwhile, a German group has actually managed to get the Wittig brothers to release (most) source code for the scope, and the code is now available on SourceForge.net. But this is still missing a rather important hardware description component, so it cannot be used or recompiled yet. The C++ code looks like it was written by a 10-year old with a TRS-80 BASIC programming background. Ugly and unreadable as hell, with little hope of being salvageable."

Dave.

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Reply to
David L. Jones

What about this, then:

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Not too far from 350 Euros.

It's both the hardware and the software, it seems from the page. Noisy inputs and really horrible software as well. Might make an interesting starting point for DIY, except that there are functional units to be had without all the bother and not so far away in price.

Jon

Reply to
Jon Kirwan

If you only had a 20MHz Lucky-Goldstar before, it is just great.

Due to the W2022A's shortcomings like noise and slow response I am currently using both: The Welec for most digital things, like serial protocols and a TEK464 for the stuff, the DSO cannot handle.

I am sure, it is.

The original internal software is as bad as the sources, we are working on, are. But some problems already have been solved:

- less noise with improved ADC/DAC-calibration, faster display, working FFT, screenshots and download of data working, improved quick measure, improved triggers and some more.

That's why I asked, wether any users of those scopes are reading here and what firmware version they are using.

Falk P.S.: A screenshot of the new but not yet finished FFT-function:

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Reply to
Falk Willberg

On a sunny day (Wed, 08 Jul 2009 15:46:48 -0700) it happened Joerg wrote in :

I have been looking at the block diagram of that scope. I uses 4 x ADC in 'staggered' sequential mode to get 1G samples/second. So each ADC samples every 4 nS. To have a bit reasonable sampling, the samples must be equally spaced. If you allow 10% error (well that is not very good is it?), then the positional accuracy should be 100 pS ? But 10 pS would be better :-) I dunno how they do that:-), maybe a delay line? Temp drift? Hopefully not done with gate delays in the FPGA???? So what is their 1G samples really worth? I like the fact that the design is open, and I if I had one for free, say found it on the door step, I 4 sure would have a go at the soft... But you are stuck with the hardware... Also what good is an 8 bit ADC if you have 3 bits of it unstable and showing up as noise, as in that picture?

For about 520 Euro you can buy a Rigol with 1G samples, have not tried those, but you know, guarantee, service...

Reply to
Jan Panteltje

Not much, almost a gimmick really.

Pretty crusty huh?

The Rigol uses a genuine 1GS/s sampler, developed by them, they were the first one apart from the "big boys" (Agilent, Tek, Lecroy et.al) to do their own at that speed. The Rigol is so good (for that price level) that Agilent have been rebadging them for years.

Interesting fact, Rigol are the #2 scope manufactuer in the world by volume.

$520 euro? try $320euro for the DS1052E on Ebay. Granted, only 50Mhz analog bandwidth, but you get a genuine 1GS/s in real time, and that deep memory is so nice.

Dave.

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Reply to
David L. Jones

They are quite good but heavy. A client bought some.

Right. Or pay a little more and get a good Asian scope.

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Reply to
Joerg

Wasn't that a cigarette brand? SCNR ...

Yes, now I remember you mentioning that in the German NG.

So what was the SW guy at Wittig doing? Couldn't get it done? Overloaded with other work?

Ganging four ADC is not quite trivial. Have done it, with auto-calibration and all. The cardinal rule is not to fall for digital delay lines, those can be the pits.

I have never seen one in America but maybe some of our Brits have?

Nice!

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Reply to
Joerg

The Instek GDS-2204 in the lab here does it like that as well. So does gear that I've designed. You can track ADCs so precisely that the error is way below their quantization granularity. But you must auto-calibrate all three parameters: Clock phases, offsets, gains.

Screwed up layout? That shouldn't happen.

Yep, several Asian mfgs these days. And some can give Agilent and Tek a run for the money in the low-end sector. I've had situations where the Instek scope here out-maneuvered a more expensive Tek.

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Joerg

Jan Panteltje schrieb:

...

As I am using Linux, I am quite happy with the open source. So I was able to add functions *I* wanted to have.

Also very important: It has a lot of "Spielwert", (if someone could translate that, please ;-) ) and I don't want to use a 30 MHz analog LG5020 (or so) for 300¤ any longer...

Wittig gives 3 years warranty. And I was told, that they really repair or replace.

Falk

Reply to
Falk Willberg

Offering an open source scope platform is actually a brilliant business idea. They'll be the only ones because the others are extremely restrictive. I wanted to fix some minor things on my DSO and asked for the keys to the firmware. The answer was a firm "You can't have those".

Fun factor. So you are probably not married :-)

But always keep an analog scope around. DSOs can seriously fool you in some situations and it's also next to impossible to detect slight noise effects.

Wasn't there a bankruptcy? At least in the US warranty rights are pretty much toast after that.

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Reply to
Joerg

On a sunny day (Thu, 09 Jul 2009 17:36:08 +0200) it happened Falk Willberg wrote in :

You mean on the PC side? That website says they cannot install new firmware yet?

I once bought a calculator in London. It did not even add 1+1. Brought it back, the guy told me: O, I gave you the UK version, here is the same one made in the US. That one worked.

Reply to
Jan Panteltje

Jan Panteltje schrieb:

On both sides.

What website says that? The open source firmware *is* *working* much better than the original. The latest release is 0.82, see

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Falk

Reply to
Falk Willberg

Sometimes I think that those developers feel ashamed of their code ;-)

Thanks.

She beleives knitting is fun. I beleive, burning my fingers, fixing things, writing software is fun ;-)

AFAIK the Welec GmbH went bancrupt. But now Wittig Electronics GmbH sells the scopes.

Falk

Reply to
Falk Willberg

On a sunny day (Thu, 09 Jul 2009 19:30:55 +0200) it happened Falk Willberg wrote in :

the one (of many) I was on, cannot find it back, but it did say some essential part was missiing.

OK.

Reply to
Jan Panteltje

Which newsgroup is this. I'd like to start reading it. I need to work on German -- especially technical terms.

Thanks, Jon

Reply to
Jon Kirwan

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