Author Topic: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...  (Read 53850 times)

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Offline tinhead

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The app menu i found it pretty ridiculous: it's not a computer nor a cell phone...

Application menu/button is nothing new, you can find it on Tektronix TDS500/600/700/3000 as well  :rant:
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Offline JackOfVA

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Excellent video and not overly long at all.

Perhaps the most useful "take away" from the video is how poor a job a spec sheet does at conveying the "fit and finish" as it's known in the automotive field -- those things that distinguish an also-ran product from an outstanding product.

 

Offline max-bit

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short
Too many errors in the oscilloscope.
As for the nearly $ 3,000 it is a very weak oscilloscope.
The 2.8 k $ can be RIGOL DS4022
Or 3,2 k $ DS4024
Which class is better than the crap GwInstek
This is a mistake, not an oscilloscope
This is already my oscilloscope Owona SDS8202 is better.
Maybe another software will improve ... maybe ... ?




 

Offline tinhead

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Too many errors in the oscilloscope.

you must be fucking blind, are you?

I don't want to be human! I want to see gamma rays, I want to hear X-rays, and I want to smell dark matter ...
I want to reach out with something other than these prehensile paws and feel the solar wind of a supernova flowing over me.
 

Offline arekm

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There's no fast forward button in YouTube. I wish there was.

Press right arrow key on your keyboard.
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http://readme.maven.pl/
 

Offline marmad

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Until someone does a more comprehensive (and perhaps objective) measurement of it's waveform update rates, this is the only thing we have at the moment (from the Trigger out signal). I'd like to see my 'either' Edge trigger method used to test it.
It now appears Instek's Short record length is NOT 1M (as stated in the manual), but is instead 1k. That means, for example, that the 80k wfrm/s is being done with a sample rate of 200MSa/s, effectively reducing it's available BW (and the same is true for all of the >50ns time base settings).
« Last Edit: June 05, 2013, 10:34:38 am by marmad »
 

Offline Hypernova

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I would looove to support my fellow country men but after this video...

 |O |O |O |O |O
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Offline Hydrawerk

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Marmad, thank you for the table. Who created it? Was it Grego?
The table looks like this Tek DPO2000. The waveform update rate goes down at 50ns/div.
This GDS-2000A looks way worse than Rigol DS2000. Here's the table created by marmad:
www.eevblog.com/forum/testgear/first-impressions-and-review-of-the-rigol-ds2072-ds2000-series-dso/?action=dlattach;attach=32606
« Last Edit: May 27, 2013, 05:17:44 pm by Hydrawerk »
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Offline Hydrawerk

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And please note that this table

is different from Kiriakos measurements, because Kiriakos was probably wrong. http://www.ittsb.eu/GDS-2102A%20Wfms%20measurments.html
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Offline marmad

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I believe I've figured out what the problem is with the intensity grading on the Instek:

Even before Dave's video, I had found it rather strange when looking through the specifications that GW-Instek doesn't specify ANYWHERE how many levels of gradation they do.

Agilent specifies 64 levels - Rigol specifies up to 256 levels - but Instek just says 'multiple'. Well, I analyzed EVERY uncompressed screenshot posted online that I could find from the GDS-2000A - and it appears the reason the grading looks bad (both intensity AND color) is because they're using a maximum of 16 LEVELS of grading (or 16 different colors simultaneously). This would also, of course, help them achieve faster wfrm/s rates.

The attached image shows a Rigol screenshot with 54 levels compared to two screenshots from the Instek with 12 and 15 respectively.

Now if this is incorrect, and it's possible to adjust the Instek for a finer gradation, I'd like to know about it. But so far, the evidence suggests otherwise.

« Last Edit: May 27, 2013, 08:22:54 pm by marmad »
 

Offline senso

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It seems the screen stutters/jerks/not continous, instead you have nice waves for 1 second, them a little pause, them more nice waves, another stop, it feels like the thing is underpowered and from time to time the cpu just hangs doing something else, it is so annoying looking to the screen.
And the user interface, oh god  :palm:
And those little add-on cards, there is 3 options, you can only have two of them at a time, and the sig-gen is really crap, basic wave-forms, if you want two outputs, then buy to add-ons, and can't use any other add-on, and almost 3K is a lot of money for such a basic product.

About the movie lenght, its perfect, just put it playing, reply to some other foruns, watch a bit, do something else, there is not that much content that you really need to see, just hear Dave complain about it
 

Offline jahonen

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I believe I've figured out what the problem is with the intensity grading on the Instek:

Even before Dave's video, I had found it rather strange when looking through the specifications that GW-Instek doesn't specify ANYWHERE how many levels of gradation they do.

Agilent specifies 64 levels - Rigol specifies up to 256 levels - but Instek just says 'multiple'. Well, I analyzed EVERY uncompressed screenshot posted online that I could find from the GDS-2000A - and it appears the reason the grading looks bad (both intensity AND color) is because they're using a maximum of 16 LEVELS of grading (or 16 different colors simultaneously). This would also, of course, help them achieve faster wfrm/s rates.

The attached image shows a Rigol screenshot with 54 levels compared to two screenshots from the Instek with 12 and 15 respectively.

Now if this is incorrect, and it's possible to to adjust the Instek for a finer gradation, I'd like to know about it. But so far, the evidence suggests otherwise.

I think this is only a part of the problem, like I mentioned in the another thread, another part is that it seems to miss "density shading" (electron beam velocity modulation in analog scopes) like in Agilent and Rigol DS2000 (I do not have one to check but I think it works like that). That thing makes it possible to take a single-shot of AM-modulated signal and still see analog scope-like result.

Regards,
Janne
 

Offline tinhead

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Well, I analyzed EVERY uncompressed screenshot posted online that I could find from the GDS-2000A - and it appears the reason the grading looks bad (both intensity AND color) is because they're using a maximum of 16 LEVELS of grading (or 16 different colors simultaneously). This would also, of course, help them achieve faster wfrm/s rates.

i don't think you can speed up data capture by reducing grading depth, DPO-core will simply add data and run next capture, display processor will count
depth value and calculate color/grading. This can only have influence on UI speed, especialy when doing measurements on the accumulated wave "depth" data.

Btw, 16 levels was 12 yrs ago a good value for state of the art DSOs:

http://www.hit.bme.hu/~papay/edu/DSOdisp/gradient.htm
I don't want to be human! I want to see gamma rays, I want to hear X-rays, and I want to smell dark matter ...
I want to reach out with something other than these prehensile paws and feel the solar wind of a supernova flowing over me.
 

Offline marmad

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i don't think you can speed up data capture by reducing grading depth, DPO-core will simply add data and run next capture, display processor will count
depth value and calculate color/grading.

You're probably correct - but I reserve the right to think about it a bit more to see if I can come up with a way that it might use less levels to squeeze out more wfrm/s. ;)

I just have to wonder if changing the persistence time would somehow alter the number of levels used for grading. Normally you would think it shouldn't - but maybe they're doing something slightly strange with it.
« Last Edit: May 27, 2013, 08:19:37 pm by marmad »
 

Offline Hydrawerk

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and the sig-gen is really crap, basic wave-forms, if you want two outputs, then buy to add-ons, and can't use any other add-on, and almost 3K is a lot of money for such a basic product.
You will never get a two channel function generator.
See this: https://www.eevblog.com/forum/testgear/gds-2000a-new-economic-oscilloscope-by-gw-instek-comes-to-market/?action=dlattach;attach=48888;image
And maybe read this manual:
www.eevblog.com/forum/testgear/gds-2000a-new-economic-oscilloscope-by-gw-instek-comes-to-market/?action=dlattach;attach=48887
EDIT: Unless GW Instek makes an firmware or hardware update. Do they do it often?
« Last Edit: May 27, 2013, 09:01:26 pm by Hydrawerk »
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alm

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Never? That is a very strong statement. Both firmware and manuals are subject to change. It would be a major screw up if they designed in two connectors and output stages without ability to use both at the same. My guess is that the limitation is firmware, which may or may not get fixed.
 

Offline senso

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Now that is DUMB..
Two BNC's in the front for what?
If they both perform the same what is the advantage, being able to swap to BNC 1 or BNC 2, now that is really dumb..
 

Offline tom66

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I don't expect that GW Instek have got custom silicon. It will be done on an FPGA or three. We will see when it comes to the teardown.
 

Offline madires

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Now that is DUMB..
Two BNC's in the front for what?
If they both perform the same what is the advantage, being able to swap to BNC 1 or BNC 2, now that is really dumb..

The hard-wiring was cheaper than a relay to switch between modules :-)
 

Online EEVblog

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Until someone does a more comprehensive (and perhaps objective) measurement of it's waveform update rates, this is the only thing we have at the moment (from the Trigger out signal). I'd like to see my 'either' Edge trigger method used to test it.

Why?
The trigger out is the ultimate method, unless you think the Instek's trigger out is faulty? The max value matches their quoted figure.
 

Offline Hydrawerk

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OK, but who created that table?
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Offline grego

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OK, but who created that table?

Might be off my video - not sure - but the numbers in the high range correspond with what I've seen - until I get a proper function generator set up (soon!) I can't vouch for the outlier values though.
 

Offline marmad

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Why?
The trigger out is the ultimate method, unless you think the Instek's trigger out is faulty? The max value matches their quoted figure.

Apparently the trigger out voltage is quite low, so there have been conflicting measurements at some settings. Also, I posted that before I'd figured out that the problems with the intensity gradation had to do with Instek only using 16 intensity levels - so I thought they might be update related.
 

Offline Hydrawerk

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the trigger out voltage is quite low
That's bad, because there is no problem with measuring Trig Out of DSOX2002A or your DS2072 with a common multimeter (with counter). A normal scope has a proper output level.
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Offline marmad

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That's bad, because there is no problem with measuring Trig Out of DSOX2002A or your DS2072 with a common multimeter (with counter). A normal scope has a proper output level.

You can easily measure it with another DSO. In fact, on the Rigol, you can just run the Trigger Out back into channel two and use the frequency counter to see the waveform rate. It's slightly slower because you have both channels on - but not by much - it's close to the same frequencies you get when measuring a single channel with an external counter.
 


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