Author Topic: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...  (Read 50919 times)

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Offline firewalker

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Those fast alternating colors could easily give you a seizure...  :P :P :P

It was like to anime warriors fighting with light swords.

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Offline marmad

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@Dave - Perhaps some different combination of the persistence time and intensity level gives a better result for the waveform grading?

If it doesn't, that's certainly not well-implemented.
« Last Edit: May 27, 2013, 01:06:31 am by marmad »
 

Offline tinhead

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Dave,

you probably worked much more with Agilent than TEK scopes  :scared:, the color grading is beautiful thing.
In the last minutes of your video, you can see glitches coming with different color, i always liked this on TEK
when color grading enabled. On the other side, when using single color, there should be better intensity
implementation (right, like on Agilent/Rigol/Hameg).


The glitch you saw on moduleated signal, probably coming from DMM module enabled or the digital filter (i think it was still on)
« Last Edit: May 27, 2013, 12:27:31 am by tinhead »
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Offline firewalker

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Ethernet and VGA out are modular? You have to remove the function or the logic analyzer?

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Offline madires

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I got mixed feelings about the GDS-2000A. Some stuff is designed badly, but there are also some nice features. The firmware looks very beta, the function generator is a bad joke, the blue border on the screen stealing real estate, the cumbersome frequency setting and so on. If this would be the very first scope of new no-name company for €1299 I'd say it's ok and two or three firmware updates are going to fix most software and UI issues. But for US$ 2700, no thanks!

And for a more gerenal rant, I dislike that culture of selling the same hardware capable of x MHz for different prices while limiting the bandwidth by software to create some virtual price levels. That means that I pay for the fully fletched hardware anyway but have to pay for a byte in the firmware a lot of money extra. There's no difference in development or production costs, it's just a stupid idea of marketing! For me that's a rip-off, plain and simple.

BTW, a local company is selling the 2304A for € 3500. It's hard to believe that!
 

Offline Hydrawerk

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http://www.eevblog.com/forum/testgear/gds-2000a-new-economic-oscilloscope-by-gw-instek-comes-to-market/315/
Also see this long thread.
Quote
The firmware looks very beta, the function generator is a bad joke
Especially after Rigol releases their DS2000-S with 200Ms/s 25MHz arbitrary function generator.
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Offline free_electron

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about the looks : the buttons on the rigol are too close together. the front panel is too 'busy'. i kinda like the spread-out look of the instek. Everyting nicely lines up on the instek (controls and bnc)

the only thing that looks a bit cartoonsih on the instek are the 'bubbles' . like the round dots around the vertical settings , the round buttons right of the display and the oversized klunky round power button.

not having pushable encoder ( alternate function) is a bit of a turndown. like you said ( autocentre , centre trigger point etc .. ) the cost between a pushable encoder and a non-pushable is negligible ( we're talking a few cents... ) so yeah , that's inexcusable.

no autoprobe is simply because the probes they supply don't have that capability.

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Offline Hydrawerk

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For some reason even Tektronix almost never uses pushable knobs. I wonder why?? I love pushable knobs.
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Offline marmad

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There's no difference in development or production costs, it's just a stupid idea of marketing! For me that's a rip-off, plain and simple.

Not to agree or disagree about the policy - but I think the point is that the company can recoup research and development costs for the whole series more quickly by spreading it out between many models. If they just sell a 300MHz BW DSO for $X, they're less likely (or it will take much longer) to start making profit than if they sell 300MHz for $3/4X, 200MHz for $1/2X, and 100MHz for $1/4X (or something like that).
 

Offline free_electron

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There's no difference in development or production costs,



you really do not understand economy of scale when it comes to integrated circuits.

you are making 4 scopes :
1 - 4 channel 200 mhz 1 million points  4gs/s
2 - 4 channel 200mhz 4 million points 4gs/s
3 - 4 channel 500mhz 1 million points 4gs/s
4 -  4 channel 500mhz 4 million points 4gs/s

50% of the buyers  go fo rmodel 1
25% go for model 2
20% go for model 3
5% go for model 4.

you assume there will be a total of 1 million scopes sold.
half a million model 1, quarter million model 2 etc ..

if you need to write off the development cost  of model 4 over the volume you will sell these will be very expensive machines.

The maskset for a typical scope asic is around 4 million $ ... these days. so you are burning 12 million $ to cover 50% of your targeted volume ! ( models 2,3 and 4 combined are 50% )

and you need to make 4 boards, etc ..

now, if you make the thing programmable. you pay for 1 maskset that covers 100% of the scopes.

The cost of the chip itself ( the cost of producing the silicon , assuming everything else is already paid for ) is purely dictated by square millimeter. having a chip with 1 megapoints go to 4 megapoints adds maybe a square millimeter ... which will cost you 1 $ ...

but, throw in the development and mask cost ( if you are only going to sell 50000 of those machines and that all of a sudden becomes a much more expensive chip !. )

if you make 1 million chips . the chip itslef costs you 5$ in silicon and 8$ in mask cost and add in 20$ development cost (10 million dollar to design it spread over half a million chips) . let's say 30$ total

for the chip for the hi end machine : it will stilll cost 7$ ( slightly larger area ), but now you tack on the 10 million dollar split over 50000 chips... which is is 200$ and the mask cost split over 50000 chips... which is 80$ ..

and the chip will cost roughly 300$ ... . add all that stuff up for your 4 designs and thats a lot of money !

do everything with 1 chip.  7$ in silicon (we're always using largest die ) , 4$ in mask ( 4 million spread over 1 million chips now ) and 10$ devcost ( 10 million spread over 1 million ) and that chip costs you 21$ ..

you can't beat that price. The most profitable solution is to mass produce the high end chip and simply disable functions.  the cost of the silicon is nothing compared to the design and the startup cost !

that is the reality of semiconductor production.
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Offline tinhead

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that is the reality of semiconductor production.

and btw, this is the case for DSOs since 15+ years, e.g. you can take cheap ass TDS540B, change 8 resistors to make the scope to think "i have color dac"
(and then make use of external monitor or course), change another 3 resistors to make the scope thinking "i'm TDS784A", recalibrate it and now
you have 4GS/s max (1GS/s on all 4ch), 500kpoint memory and 1GHz scope instead of 2GS/s (500MS/s on all 4ch), 50kpoint memory, 500MHz bw scope.
No idea what was the list price of TDS540B (TDS744A was however 17k USD), but TDS784A was 34 USD (+3k for 1Mpoint memory). So already between
744A and 784A we have 17k USD diff!, for 3 resistors ( and sharing of development costs of course).

madires,

and yeah, nobody was complained about, you will find as well other manufacturers/models from last +10 years doing the same, and i'm glad it's like that,
i don't want to pay development twice.
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Offline madires

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do everything with 1 chip.  7$ in silicon (we're always using largest die ) , 4$ in mask ( 4 million spread over 1 million chips now ) and 10$ devcost ( 10 million spread over 1 million ) and that chip costs you 21$ ..

you can't beat that price. The most profitable solution is to mass produce the high end chip and simply disable functions.  the cost of the silicon is nothing compared to the design and the startup cost !

that is the reality of semiconductor production.

I wouldn't expect anything else. If there would be different input circuits or whatever for the different models I'd accept also different prices. But if it's just a single byte in the firmware to determine the bandwidth while the hardware and the features are 100% the same for all models it's hard to explain the price difference. Why not just have the top model (2 and 4ch)? I know, you have to provide models in the right price range for the different target groups of buyers. In your example you estimated 5% buyers for the top model. If you do a mixed calculation over all the models and expected sales you'll end up with the price of the low-midrange model. If hardware and software are the same simply sell only the "top" model for the price of the low-midrange one. You will even sell more because the buyers see a fair pricing and top bandwidth becomes more affordable.
 

Offline free_electron

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uhhuh. but, so far we have only calculated the cost of the machine... if you sell your 1 million scopes you end up with 0$ at the end of the run... so where will you get the money for the next design ? ( which will be more expensive because you need to  develop new features , higher speed , ore expensive board and chip .. )
all your employees also need money ...

you need to get profit from each category. so 500.000 scopes at 100$ dollar profit means that for the 50.000 scope you need 1000$ profit.

thats how you balance it out. your low end scope is cheap and the high-end machines cost money. so each category attributes the same amount of profit.

and we haven't looked at the shareholders. the reason for existence of a company i to give shareholders a return on their investment... not to provide you with a scope at cost...
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Offline marmad

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about the looks : the buttons on the rigol are too close together. the front panel is too 'busy'. i kinda like the spread-out look of the instek.

Gotta agree with Dave here - I don't know if you've used the Rigol, but the knobs and buttons don't feel too close together at all - they feel just right. Plus the horizontal scale knob is where it 'should be' - by the edge of the display.

And from what I can tell from the video, the UI is just much better overall on the Rigol - from the multifunction knob you can push any time to adjust the intensity  - to the use of two knobs (multifunction = fine & navigation = coarse) whenever you're adjusting a value with a large range. It might look more crowded, but from an interface standpoint it's much more clever.
 

Offline SeanB

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Good first version, at least the hardware is there, just needs a lot of UI changes and upgrades. Hopefully this gets back to the design team and they look into putting this into a firmware upgrade and a few production changes to improve it. At least the UI is field upgradable reasonably easily.

Looking at the plugins they look like standard PCI card slots ( good to 400MHz and already cheap and a well proven connector) and possibly they are using standard PC bus layout with only a few dozen pins allocated to do the additional functionality needed from the module. As the FG moved with the module I would think they used 16 differential pairs of lines as IO, and one pair for the FG output. the logic pods probably have a little intelligence in them as well, likely the comparators, trigger point voltage source and an ID chip for an internal I2C bus.

As to the differences I would say they make a single board for all four options, just not populating the input channels for the extras, but then just have the firmware with an option byte set to do the various options. Having a common input circuit makes manufacture easier, the difference in price between a 100 and a 400MHz opamp will not be much per unit when you buy in 100k lots, and buying only the one at high volume will probably work out cheaper than having the 2 stock items and then having to make 2 boards with different components and layout on each.
 

Offline tinhead

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Plus the horizontal scale knob is where it 'should be' - by the edge of the display.

why??? The timebase section near trigger section makes more sense, far from display.
Near display other things need to be implemented (like intensity, multiknob, etc., but not horzontal scale).

This is for me so self-evident as the fact that Rigol DS2xxx is having crap buttons left and right side of the display,
and then two menu, and 4 menu top/buttom .. why? Is it really necessary to overload display near area with
useless things?
« Last Edit: May 27, 2013, 03:19:13 am by tinhead »
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Offline madires

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uhhuh. but, so far we have only calculated the cost of the machine... if you sell your 1 million scopes you end up with 0$ at the end of the run... so where will you get the money for the next design ? ( which will be more expensive because you need to  develop new features , higher speed , ore expensive board and chip .. )
all your employees also need money ...

you need to get profit from each category. so 500.000 scopes at 100$ dollar profit means that for the 50.000 scope you need 1000$ profit.

thats how you balance it out. your low end scope is cheap and the high-end machines cost money. so each category attributes the same amount of profit.

and we haven't looked at the shareholders. the reason for existence of a company i to give shareholders a return on their investment... not to provide you with a scope at cost...

What's wrong with simply adding up all costs, future R&D, profits and so on and dividing that by 1M scopes (considering 2 and 4ch versions of course)? The method you described creates artificially low price scopes and high price scopes which are the exact same product but one byte in the firmware. The high price scopes subsidize the low price ones. In average the company will make the same profit by numbers. But if the company is able to sell the scope for less than the competitors (with the artificially pricing) while making the desired profit it will even sell more scopes because of that. The scope will be more expensive than the low price version of the competitor, but it offers 300MHz vs. 70MHz at the price of the 150MHz, maybe it's just 200-300 bucks more than the 70MHz. That wont work for the $250-350 market but for the market above $1000.

Let's assume for example:

Vendor #1
300MHz 2ch $1400

Vendor #2
70MHz 2ch $1000
100MHz 2ch $1200
200MHz 2ch $1700
300MHz 2ch $2300

Both vendors got nearly the same models with the same features and done a proper calculation. Vendor #2 offers bandwidth just by software option (all models same hardware and features). Which scope would you buy if you're looking for a 2ch with a bandwidth of >= 100MHz (assuming the scope offers all the features you need)?


 

Offline marmad

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why??? The timebase section near trigger section makes more sense, far from display.

More sense? One could mount a logical UI argument for positioning it anywhere - but it comes down to what you prefer. I prefer it near the display - and so does Dave, it seems. But you don't.
 
Quote
Near display other things need to be implemented (like intensity, multiknob, etc., but not horzontal scale).

Yes - those things ARE implemented near the display on the Rigol - as is the horizontal scale - which makes sense to me.

Quote
This is for me so self-evident as the fact that Rigol DS2xxx is having crap buttons left and right side of the display, and then two menu, and 4 menu top/buttom .. why? Is it really necessary to overload display near area with useless things?

There is nothing useless near the display on the Rigol - everything has a function - and in any case, none of the buttons are 'in the way' of the display. To me, the interface is fluid and intuitive. But really, I learned a long time ago that trying to argue about interface preferences is a waste of breath - either's Dave's complaints rang true for you - or they didn't - but there is no correct answer.
« Last Edit: May 27, 2013, 08:32:41 am by marmad »
 

Offline tinhead

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... but there is no correct answer.

i worked in last 15yrs (mostly) only with TEK and Yokogawa scopes (ok, in last 3 yrs also ~2.5 with Tekway), this is why i can easy recognize/identify
things what looks&feel TEK (Yokogawa is here anyway special). Dave did it with Agilent gears, so he can identify himself better
with their UI/look&feel.

So the correct answer is - use what you like to use (but be open for new things as well)
« Last Edit: May 27, 2013, 08:47:01 am by tinhead »
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Offline Hydrawerk

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Well, if you get used to Tek and Yokogawa, then you find Rigol completely different. But I like the dedicated measurement menu on left side of display...
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Offline nitro2k01

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I believe the problem at 52 minutes into the video is an aliasing problem. The sample rate (the rate of samples actually used for the display) and frequency of the signal happen to line up in such a way that you get a line like that. Annoying.
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Offline marmad

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So the correct answer is - use what you like to use (but be open for new things as well)

BTW, I hope you noticed in my original comment about the placement of the horizontal scale knob I wrote the phrase 'should be' in quotes - to indicate that I was joking - and I knew it was just personal preference. ;)
 

Offline EEVblog

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@Dave - Perhaps some different combination of the persistence time and intensity level gives a better result for the waveform grading?

Yeah, perhaps. This was a direct side by side comparison though, and in this particular case it's came out 2nd best.
It may indeed work better under other conditions.
 

Online IanB

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Not sure I will watch to the end of the video (1 h 12 m long? Are you kidding me?), but at the beginning I do not find anything bad about the control layout. Everything is nicely organized and separated. There is no obvious case of multi-function knobs, which is a good thing for usability.

(There is a maximum watchable length for videos of 20-25 min. Seriously. Please get that machete and edit out the filler. Slash and burn baby, slash and burn!)
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Offline marmad

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There is a maximum watchable length for videos of 20-25 min. Seriously.

Says who?

Quote
Please get that machete and edit out the filler. Slash and burn baby, slash and burn!

Just skip the parts you don't want to watch. I enjoyed watching the entire thing - it made my train trip to Paris more enjoyable. In fact, there are so many textbook examples of bad choices in the firmware (the method of setting the frequency of the FG was a classic) that I'm thinking of using parts of it in the next class that I talk about interface design in.
« Last Edit: May 27, 2013, 11:32:25 am by marmad »
 

Offline c4757p

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There is a maximum watchable length for videos of 20-25 min. Seriously.

I disagree as well.
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Online IanB

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Says who?

Says me and video journalists the world over. Rules #1, #2 and #3 of content production are "cut out the fluff". Make every word (or minute) count.

Quote
Just skip the parts you don't want to watch.

There's no fast forward button in YouTube. I wish there was. Considering that YouTube comes after VHS and DVD players, it is remarkably lacking in the user experience.
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Offline Hydrawerk

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I like Dave's video. Yes, it's longer than usual, but why not? It was full of useful information, that you don't get anywhere else. Dave, for you  :-+ :-+ :-+.
There are shorter videos, too. But it's not very informative.

The intensity grading looks a bit better, maybe caused by the camera?
And you can hear some noise. Does it come from the fan?? :scared: :scared:
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Offline Hydrawerk

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Rules #1, #2 and #3 of content production are "cut out the fluff". Make every word (or minute) count.
Oh, slow down. Dave's videos aren't fast CNN TV News but rather a movie or documentary.

Quote
There's no fast forward button in YouTube. I wish there was. Considering that YouTube comes after VHS and DVD players, it is remarkably lacking in the user experience.
Yes, I miss that. Once I found a strange casette at a trashcan. I put it in grandma's VHS player and there was some oldschool dirty German porn. I watched it in 3× speed or so. It was an unmatched experience.  :-DD :-DD O0 :palm:
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Online Lightages

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There is a maximum watchable length for videos of 20-25 min. Seriously.

I disagree as well.

If this was the US and TV time, then yes it is true. Don't say anything on TV that can't be believed or understood or agreed upon by the unwashed viewer. If you must say something that is the least bit obtuse or controversial, then be able to back it up in 10 seconds or get walked over by the next sound blip that needs to be blasted out to keep the TV zombies from flipping the channel.

But this isn't US TV, this is an captive audience that has a special need, the need for real information. One cannot cover a subject like this scope in 20 minutes without making it sound like an infomercial. Could Dave have made it a bit shorter? Yes, but not that much.

Back on subject:
Based on the video, I will not be buying one of these. Way too many quirks and glitches for my liking.
 

Offline marmad

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Says me and video journalists the world over.

Ahhh... good to know it's video journalists the world over. I was slightly concerned that it was video journalists from just 4 out of 5 of the world's continents.

Quote
There's no fast forward button in YouTube. I wish there was. Considering that YouTube comes after VHS and DVD players, it is remarkably lacking in the user experience.

Well, if you feel compelled to actually watch the entire video streaming from YouTube (not sure why you would, but TETO), there is a drag-forward handle - a 21st century equivalent.
« Last Edit: May 27, 2013, 11:57:39 am by marmad »
 

Offline David_AVD

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I must admit I went to watch it, but bailed out when I saw the run time.  That's just my reaction of course.
 

Offline KaloyanP

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No clickable knobs? Are you shitting me? They lost me right then and there. Why would I ever use any piece of gear with less buttons? That's why I pay MORE- to get the buttons and not have to struggle with a godawful interface.
 

Offline Stonent

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There is a maximum watchable length for videos of 20-25 min. Seriously.

I disagree as well.

I'm not even an engineer by trade and I sat through the whole thing like it was nothing and was like "darn, that was an hour?!"
Dave videos are usually pretty good time killers. He usually peters out before I do "Well folks, that's all the time I have. I've got to get home and take care of Sagan etc"
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Offline EEVblog

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Says me and video journalists the world over. Rules #1, #2 and #3 of content production are "cut out the fluff". Make every word (or minute) count.

This is precisely the kind of comment I expected from this video (because it always happens and is so predictable)
The nature of how this video was shot does not dictate itself well to hack'n'slash editing. If you were a content producer then you would understand this.
I made it very clear in comments what this video was, it is a long informal video of random playing around and associated comments.
If you don't like this style of video then don't watch it. But do not make the mistake of thinking that is can be magically edited into my usual formal review style of video.
 

Offline EEVblog

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I must admit I went to watch it, but bailed out when I saw the run time.  That's just my reaction of course.

Sure, and that's human nature.
Others will balk at 45min, others 30min, others 15min, others 5 min.
I'd probably have 10 times the audience I do if I kept all my videos to 5min, but that's not my style.
 

Offline EEVblog

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But this isn't US TV, this is an captive audience that has a special need, the need for real information. One cannot cover a subject like this scope in 20 minutes without making it sound like an infomercial. Could Dave have made it a bit shorter? Yes, but not that much.

Everyone has to understand what this style of video is.
I went into knowing that:
a) I knew absolutely nothing about the scope
b) I only wanted to spend an hour or two tops unboxing and playing and recording (a proper 1hr review video would normally take all day to shoot)
c) I was not going muck and around and learn stuff and set up shots etc and then press record. It is basically leave camera rolling and record, and work with whatever material I captured.
d) The deliberate intention was to do a long rambling video of me unboxing it and my first impressions. This is a deliberately different style to a review.

Now when you go into a video like that, the end result is always going to be a non-concise rambling and long video.

Could it have been shorter with the material I had? Yes, but not by much as Lightages said, and it would be a choppy mess.

The only way to make the video more "bang per minute" is to go into it knowing it's going to be a full review and expend 5 times the effort and time doing so. In which case I'd be able to cover twice or three times the material I did in this video for the same length or less.

Now, people can argue all they want over the merits of one style vs the other, but it will, as it always does, come down to the fact that you can't please everyone. I deliberately made this  video for those who like my unboxing/first impression videos. If you don't, then that's fine, I fully expect that. But please, no complaints about it.
« Last Edit: May 27, 2013, 01:24:23 pm by EEVblog »
 

Offline c4757p

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I'd probably have 10 times the audience I do if I kept all my videos to 5min

And still the same total of IQ points among them.
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Offline warp_foo

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Says who?

Says me and video journalists the world over. Rules #1, #2 and #3 of content production are "cut out the fluff". Make every word (or minute) count.

Quote
Just skip the parts you don't want to watch.

There's no fast forward button in YouTube. I wish there was. Considering that YouTube comes after VHS and DVD players, it is remarkably lacking in the user experience.

Actually, youtube videos have an even better option than ff/rw: You can click on the red progress bar at any time in the video and immediately jump forward or back. Not only that, but you get a mini-screenshot of the point you want to jump through so you can skip segments manually by previewing until the screenshot changes, and clicking to select that point to play.

m
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Offline Salas

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Now, people can argue all they want over the merits of one style vs the other, but it will, as it always does, come down to the fact that you can't please everyone. I deliberately made this  video for those who like my unboxing/first impression videos. If you don't, then that's fine, I fully expect that. But please, no complaints about it.

Hints better on how intuitive a machine will be in the long run the way you did it.  :-+

P.S. Don't forget to show us if other settings made the grading appreciably better.
 

Online IanB

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Actually, youtube videos have an even better option than ff/rw: You can click on the red progress bar at any time in the video and immediately jump forward or back. Not only that, but you get a mini-screenshot of the point you want to jump through so you can skip segments manually by previewing until the screenshot changes, and clicking to select that point to play.

That option would be good if it worked reliably, but I haven't had much luck with it. Quite often it messes up the cache and resets the video to the start or stops playing completely until I reload the page.
I'm not an EE--what am I doing here?
 

Offline c4757p

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Which platform are you on? It's quite reliable for me (Linux 3.7 x86-64, Google Chrome 27.0.1453.93, external Flash plugin 11.2.r202).
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Offline EEVblog

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That option would be good if it worked reliably, but I haven't had much luck with it. Quite often it messes up the cache and resets the video to the start or stops playing completely until I reload the page.

I get the the occasional issue with it, but for the most part it works well. I love the thumbnails, that feature is brilliant.
 

Online IanB

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It's not the platform that makes the difference, it depends on your geographical location and whichever server you get directed to on the CDN, the time of day, and the server load. Google changed YouTube delivery so that it no longer caches ahead on your local machine, it streams in real time and tries to stay just in front of the time point where you are watching and no further. Every time you click on the progress bar now it cancels the current stream and starts a new transaction with the server at the new time point. If the server is busy this may time out or reset the session.
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Offline skipjackrc4

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It's not the platform that makes the difference, it depends on your geographical location and whichever server you get directed to on the CDN, the time of day, and the server load. Google changed YouTube delivery so that it no longer caches ahead on your local machine, it streams in real time and tries to stay just in front of the time point where you are watching and no further. Every time you click on the progress bar now it cancels the current stream and starts a new transaction with the server at the new time point. If the server is busy this may time out or reset the session.

I have a big problem with this recently.  I've started just downloading the videos using a download manager and watching later locally. 
 

Offline EEgalitarian512

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I generally watch way more EEVblog videos than I actually post to. And I certainly don't have the depth or breath of experience that many members of this forum possess when it comes to driving an oscilloscope. However, my overall impression of the GW Instek machine is that it lacks refinement, both in appearance and functionality. I, personally, would rather pay for a machine that has fewer features with higher stability and quality - so that 99% of the artifacts on the display come from the circuit under test or the overall environment - and not from my test equipment. @Dave - I am totally good with the length of your videos - long or short - it doesn't matter. I watch them because it's YOU doing them. John
 

Offline Stonent

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When I press play on a video I always say "Hoy" along with Dave. Come on, I know some of you do as well.
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Offline mark5009

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Thanks for the video, Dave. 

I have a GW GDS-1072A-U, the baby-brother version of the unit you tested.  It is pretty similar, except less of everything (except sample memory depth, funnily enough).  Bootup time is around 18s.  The UI is pretty much the same, though only one set of menu buttons.  For me, it is a good basic scope that does what I need it to do without too much fuss.  Then, my demands are great either ;-)
 

Oracle

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I don't feel comfortable whit gw-instek oscilloscopes: I much prefer Rigols.... The app menu i found it pretty ridiculous: it's not a computer nor a cell phone... Anyway it's cheaper than agilent o tektronix ones and better than atten and lecroy...
 

Offline TheWelly888

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At first I thought - a 1 hour video?!  :o But I watched it all the way through and I was quite shocked at how poor some $3000 dollar scopes can be! Thanks for the review.

I think the strange artifacts on the AM waveform may have been due to some signal processing setting being left on from earlier?

I do have a GW Instek GDS 1152-A scope, when I purchased it, felt like better value for money than the equivalent Rigol scope (and easier to obtain in the UK!) The UI of my model is actually much better than the 2000 series one that Dave reviewed - for example there are no horizontal soft keys and only 5 vertical soft keys. My gripes with mine are: noisy fan, slow setting of trigger holdoff time, no menu escape key, no obvious way to select 1x, 10x, etc probe but I think mine is a reasonable workhorse DSO.
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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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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, 08:34:38 pm 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 28, 2013, 03:17:44 am 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 28, 2013, 06:22:54 am 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 28, 2013, 06:19:37 am 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: http://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 28, 2013, 07:01:26 am 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 :-)
 

Offline 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.
 

Offline Hydrawerk

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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. (...)
Possible on DSOX2002A, too.
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Online vk6zgo

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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 output probably depends on which hole the module is in.

If you have two FG modules,you presumably have two separately adjustable generators which may be useful in some circumstances.
That said,the implementation is pretty poor for an instrument aspiring to this price range.

In general,the clunky UI,& lack of a real equivalent of an analog display is pretty off-putting.
If I ever was going to shell out $2000 plus for a DSO,it wouldn't be this one!
 

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. 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
Very interesting link, tinhead - thanks for that! I hadn't seen a clear explanation of different methods for implementing intensity (combined with decimation) before. But given that there are so many methods outlined, I still think it's possible that levels of gradation might affect waveform update speeds - depending on how the calculations are performed. For example, with Tek's DPO architecture, they have the Acquisition Raterizer ASIC which processes captured waveforms to a 21-bit deep buffer. I would imagine that the rasterization process might be faster (thus allowing more input - i.e. captured waveforms) if the buffer were only 4-bit deep.

One thing that would interesting to know for all of the current DPO-like competitors in this price range (Agilent, Rigol, Instek), is how they implement persistence - when combined with intensity grading. I analyzed captured waveforms on the Rigol and found the following results:

The small scale at the bottom of the screen contains 64 levels of grey.



The following are the brightness levels (HSB) of a single waveform (STOPped) depending on the persistence and intensity settings - shown as minimum to (50%) to maximum intensity scale:

a) Min persistence (closest setting to NO persistence on the Rigol):  44% - (64%) - 84%
b) Any persistence setting between 50ms - 20s:  4% - (14%) - 24%
c) Infinite persistence:  7% - (27%) - 47%
« Last Edit: May 28, 2013, 08:22:11 pm by marmad »
 

Offline EEVblog

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FYI there is a review of the GDS-2000A scope in this months Silicon Chip mag.
I noticed a few errors, and no mention of the function gen module limitation, or lack of fine control. Wasn't really an in-depth review.
 

Offline thefatmoop

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not sure why this comment was marked as spam on youtube...

I read a pdf teardown on the 100mhz 1000 series instek scope and the ADCs were overclocked.Wouldn't be surprised if you find that in this model. The volts/div big knobs are just plain awful and have a tendency? to register in the wrong direction when turned slowly. The instek 1000 series menus and theme is darn close to a copy of the archaic tektronix DSOs!

teardown here btw
http://welecw2000a.sourceforge.net/docs/Hardware/GW_Instek_GDS-1152A.pdf


Stay away from instek. if you need a cheap scope get a rigol.
« Last Edit: May 28, 2013, 09:36:54 pm by thefatmoop »
 

Offline Teneyes

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I analyzed captured waveforms on the Rigol and found the following results:
The following are the brightness levels (HSB) of a single waveform (STOPped) depending on the persistence and intensity settings - shown as minimum to (50%) to maximum intensity scale:

a) Min persistence (closest setting to NO persistence on the Rigol):  44% - (64%) - 84%
b) Any persistence setting between 50ms - 20s:  4% - (14%) - 24%
c) Infinite persistence:  7% - (27%) - 47%
   aaaH , Thanks Marmad
   Now a bit  off topic.  It is hard for me to think that some persistence ( 50ms) is less light than No presistence, I guess I will have to accept (scaling, to show variations)
Also what is the meaning of Persistence in a single shot. After ghosts??  ;D
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Offline marmad

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   Now a bit  off topic.  It is hard for me to think that some persistence ( 50ms) is less light than No presistence, I guess I will have to accept (scaling, to show variations)
Also what is the meaning of Persistence in a single shot. After ghosts??  ;D

Well, it would be nice to know the exact formula being used. But it seems with the 'Min' setting on the Rigol, it means the intensity gradation is based purely on the waveforms per second. But when you start adding a persistence value to the mix (which is a frequency between 0.05 - 20Hz - or infinite), the base level needs to be different - perhaps in order to be additive.

Attached is an image of noise @ Min / 50ms / Infinite persistence (all with 100% intensity).
 

alm

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Some people include links in the description to the correct spots in the video, kind of like a table of contents.
 

Offline Pinkus

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I know you might not like this, but sticking to some kind of script might also make future reviews more concise ...
While this is true of course, it would make the videos from Dave more boring. I am watching them with great fun because one cannot predict what will happen, what Dave likes and what he will rant about.... and of course I am watching his videos because I may learn something. Thats edutainment.
And by the way: this was not a review: it was unboxing and playing around.
Peter
 

Offline Stonent

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I did think the menu system on this scope looked very 16 color-ish.
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Offline marmad

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I did think the menu system on this scope looked very 16 color-ish.

Because, unfortunately, it is only 16 colors. One thing Dave didn't like - and described as looking like the DS1052E (or something to that effect) - is the fact that GW-Instek is only using an 8-bit (256) color display (like last-generation inexpensive DSOs) instead of the more modern 16-bit (65,000) ones. 

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.

Except, of course, we now know there is no dedicated display processor - only the acquisition/display FPGA (tied to both sample and display memory) and the Blackfin. So I would say, yes, using 4-bit grading and only 256 colors for the LCD would make it possible to speed up data capture, given their design.
« Last Edit: May 30, 2013, 10:03:21 pm by marmad »
 

Offline tinhead

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... the fact that GW-Instek is only using an 8-bit (256) color display (like last-generation inexpensive DSOs) instead of the more modern 16-bit (65,000) ones. 

that display connector didn't looks like 8bit.



Honestly i don't know if there are any manufacturers using less than 16bit displays in their DSOs, Siglent even claims to have 32bit.
Of course what the firmware (actally the developer) is then dong with these available colors is different story, from the hardware point of
view there should be no DSOs with 8bit display since 3+yrs.

Btw, less funny are the option slots ... look at the picture:



so no room for LAN/GPIB when VGA or SG or LA inside ... hmm
EDIT: so no room for LAN/VGA when GPIB or SG or LA inside ... hmm
« Last Edit: May 31, 2013, 12:57:47 am by tinhead »
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Offline marmad

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that display connector didn't looks like 8bit.

Honestly i don't know if there are any manufacturers using less than 16bit displays in their DSOs, Siglent even claims to have 32bit.

Man, you are really clinging to your defense of this scope. ;)   Anyway, IMO, however you want to quantify it - their color handling (and grading) is sub-par compared to similar price range DSOs; at least in terms of 2 channel models - for 4 channels the trade-offs might be worth it.

Does it work? Yes. Does it look good? IMO, no. Even for color grading, using 64-bits reveals much more detail - and a better looking waveform display.
« Last Edit: May 31, 2013, 12:01:28 am by marmad »
 

Offline marmad

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so no room for LAN/GPIB when VGA or SG or LA inside ... hmm

That's a combined LAN/VGA module - and the GPIB module is separate - although, yes, you're right, you can't have LAN/VGA, LA, and FG all at the same time.
 

Offline grego

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Honestly, you don't want the FG as it is right now.  That's not to say they won't release a new FG module later but the current one - meh - for the same price get a dedicated device with a heck of a lot more functionality.

The slots are pretty easy from my perspective - LA and VGA/LAN.  That's just me though!
 

Offline marmad

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The slots are pretty easy from my perspective - LA and VGA/LAN.  That's just me though!

Agreed.
 

Offline tinhead

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Man, you are really clinging to your defense of this scope. ;)   


oh my gosh, no! It was only hardware fact, nothing else. That what we see on screen, by given hardware, is
actually confirmation for bad/not that good/not the best implementation, which seems to be general low-costs DSOs issue.


The slots are pretty easy from my perspective - LA and VGA/LAN.  That's just me though!

Agreed.

the slots (idea) itself is ok in my opinion, it is more the fast that you can have only 2 at same time,
so no chance to have LA/SG inside and remote control over LAN/GPIB or watch on VGA simultaneously.
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Online vk6zgo

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that display connector didn't looks like 8bit.

Honestly i don't know if there are any manufacturers using less than 16bit displays in their DSOs, Siglent even claims to have 32bit.

Man, you are really clinging to your defense of this scope. ;)   Anyway, IMO, however you want to quantify it - their color handling (and grading) is sub-par compared to similar price range DSOs; at least in terms of 2 channel models - for 4 channels the trade-offs might be worth it.

Does it work? Yes. Does it look good? IMO, no. Even for color grading, using 64-bits reveals much more detail - and a better looking waveform display.

No doubt the colour grading display is useful in some circumstances,but in my opinion,a line rate video signal is not a good test of this facility,as for this waveform,colour doesn't provide any significant improvement compared to that from a conventional DSO display

An analog display or a normal DPO display is more useful for such a waveform.
 

Offline marmad

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No doubt the colour grading display is useful in some circumstances,but in my opinion,a line rate video signal is not a good test of this facility,as for this waveform,colour doesn't provide any significant improvement compared to that from a conventional DSO display

I guess you haven't been following the discussion. This wasn't, in any way, a demonstration of when or where color grading is useful. The image was merely intended as an illustration of the extra detail visible with more levels of grading - and it was just an image I had handy to convert to 64 / 16 levels of color grading. Whether you, personally, think the extra detail visible with 2 more bits of grading is 'significant' - is another matter.
 

Offline mike1305

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FYI there is a review of the GDS-2000A scope in this months Silicon Chip mag.
I noticed a few errors, and no mention of the function gen module limitation, or lack of fine control. Wasn't really an in-depth review.

It still absolutely cracks me up how their function generator modules operate... what are they doing?
 

Offline EEVblog

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It still absolutely cracks me up how their function generator modules operate... what are they doing?

I guess it seemed like a good idea at the time!  :palm:
 

Online vk6zgo

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No doubt the colour grading display is useful in some circumstances,but in my opinion,a line rate video signal is not a good test of this facility,as for this waveform,colour doesn't provide any significant improvement compared to that from a conventional DSO display

I guess you haven't been following the discussion. This wasn't, in any way, a demonstration of when or where color grading is useful. The image was merely intended as an illustration of the extra detail visible with more levels of grading - and it was just an image I had handy to convert to 64 / 16 levels of color grading. Whether you, personally, think the extra detail visible with 2 more bits of grading is 'significant' - is another matter.

And,I guess you didn't really read my comment.

My point was that a line rate video signal was an unfortunate choice of image to use as an example.

To someone who has spent a long time (too long! ;D) looking at these waveforms in real life,neither display is useful,with the colour grading simply adding another level of obscurity to the presented display.

What you are normally interested in,are:
Burst shape & amplitude.
Blanking duration
Sync pulse duration,amplitude & rise time.
Chroma amplitude---excessive chroma information below the blanking level may be affected by sync pulse
amplitude adjustments,causing colour errors.

All of this information is presented,if poorly,in both the 16 bit & 64 bit examples.
The only obvious difference is in the actual video information,where the 64 bit example looks closer (not close,but closer) to an analog display.

I reiterate,my comment was upon the choice of example.
 

Offline marmad

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And,I guess you didn't really read my comment.

Yes, I did.

Quote
I reiterate,my comment was upon the choice of example.

Please feel free to spend your time creating and posting a better example - perhaps a more fruitful use of time.
 

Online vk6zgo

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And,I guess you didn't really read my comment.

Yes, I did.

Quote
I reiterate,my comment was upon the choice of example.

Please feel free to spend your time creating and posting a better example - perhaps a more fruitful use of time.

Gee,I'm sorry if your self esteem is so tied up in this.
I thought that I was helping the discussion along.
 

Offline EEVblog

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Instek have replied on a few points, here is their response:

Quote
At 25:46, you mentioned the waveform is jerky when the statistics function is ON…
Since you did not input signals, the GDS-2000A in under Auto Trigger mode. On the lower right hand corner Trigger counter showed more than several dozens of counts, which meant that GDS-2000A was triggered by DC noise signals.(Dave used 300MHz version which has a very sensetive trigger.) Hence, the updat rate and response was a little slow. Turn up Trigger Level or set Hi Frequency Rejection will solve the problem.
 
At 43:00, you compare the AM measurement with Rigol. GDS is far behind Rigol regard to the Intensity performance.
You set the acquisition memory into “short” mode, so the envelope of the AM signal is not solid, if you change to “Auto” mode, there will be no problem.
 

Offline marmad

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You set the acquisition memory into “short” mode, so the envelope of the AM signal is not solid, if you change to “Auto” mode, there will be no problem.

Are they saying that this is what caused the strange spikes you saw in the AM signal? Because of the sample rate derived from the memory length?
« Last Edit: May 31, 2013, 08:08:43 pm by marmad »
 

Offline EEVblog

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Are they saying that this is what caused the strange spikes you saw in the AM signal? Because of the sample rate derived from the memory length?

Not entirely sure  :-//
 

Offline marmad

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At 43:00, you compare the AM measurement with Rigol. GDS is far behind Rigol regard to the Intensity performance.

Anyway, kudos to them for at least saying this straight up.
 

Online vk6zgo

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Are they saying that this is what caused the strange spikes you saw in the AM signal? Because of the sample rate derived from the memory length?

Not entirely sure  :-//

Dave,I was going to point out that an overmodulated AM signal like you used will produce harmonics of the carrier & sidebands,as well as intermodulation products between these harmonics & the original signals.

I thought maybe the GWInstek was having problems with aliasing with these signals.
If so,it's a sampling rate problem,but wouldn't happen with a lower % of modulation.
 

Offline madires

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Honestly, you don't want the FG as it is right now.  That's not to say they won't release a new FG module later but the current one - meh - for the same price get a dedicated device with a heck of a lot more functionality.

Yep, for the same money (€249) I could buy a Siglent SDG1010. And if you consider that the scope already got the PSU, screen and knobs it's hard to believe how much GW Instek charges for 5MHz and 3 waveforms.
 

Offline grego

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Are they saying that this is what caused the strange spikes you saw in the AM signal? Because of the sample rate derived from the memory length?

Not entirely sure  :-//

If you reply back to them directly they will probably work to clear it up.  They've been fantastic at getting back to me.  Copy the guy who sent you the scope too since he's probably in marketing and wants to see positive reviews. :)
 

Offline Bored@Work

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #106 on: June 01, 2013, 01:13:24 am »
They've been fantastic at getting back to me.  Copy the guy who sent you the scope too since he's probably in marketing and wants to see positive reviews. :)

Thats how it started when we had a problem, too.  But the Taiwanese started to duck and cover and felt silent when it became difficult because their distributors messed up.

I delete PMs unread. If you have something to say, say it in public.
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Offline grego

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #107 on: June 01, 2013, 01:47:07 am »
They've been fantastic at getting back to me.  Copy the guy who sent you the scope too since he's probably in marketing and wants to see positive reviews. :)

Thats how it started when we had a problem, too.  But the Taiwanese started to duck and cover and felt silent when it became difficult because their distributors messed up.

Again I deal with InstekUSA so a different beast.
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #108 on: June 01, 2013, 03:26:22 am »
You set the acquisition memory into “short” mode, so the envelope of the AM signal is not solid, if you change to “Auto” mode, there will be no problem.

Well, assuming the Instek follows the normal math, 'Short' mode means 1M record length - and you were on 200us, so it was likely sampling at 500MSa/a - but you had the RIgol set to AUTO so it was sampling at 2GSa/s - so I guess it wasn't a fair comparison. Perhaps check it again with the same signal on AUTO and sampling @ 2GSa/s?
 

Offline mike1305

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #109 on: June 01, 2013, 03:37:36 am »
You set the acquisition memory into “short” mode, so the envelope of the AM signal is not solid, if you change to “Auto” mode, there will be no problem.

Well, assuming the Instek follows the normal math, 'Short' mode means 1M record length - and you were on 200us, so it was likely sampling at 500MSa/a - but you had the RIgol set to AUTO so it was sampling at 2GSa/s - so I guess it wasn't a fair comparison. Perhaps check it again with the same signal on AUTO and sampling @ 2GSa/s?

Short mode switches to 1,000 points of memory.
 

Offline Hydrawerk

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #110 on: June 01, 2013, 03:48:23 am »
Really 1kpoints? Is this in the manual?
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Offline grego

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #111 on: June 01, 2013, 05:03:07 am »
You set the acquisition memory into “short” mode, so the envelope of the AM signal is not solid, if you change to “Auto” mode, there will be no problem.

Well, assuming the Instek follows the normal math, 'Short' mode means 1M record length - and you were on 200us, so it was likely sampling at 500MSa/a - but you had the RIgol set to AUTO so it was sampling at 2GSa/s - so I guess it wasn't a fair comparison. Perhaps check it again with the same signal on AUTO and sampling @ 2GSa/s?

Short mode switches to 1,000 points of memory.

Incorrect sir.  From the manual:

Quote
There are two record length settings, Auto and Short. The Auto setting will set the record length to maximum record length available, dependent on the scope settings. The Short setting will set the record length to 1M.
 

Offline mike1305

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #112 on: June 01, 2013, 06:59:23 am »
Quote
There are two record length settings, Auto and Short. The Auto setting will set the record length to maximum record length available, dependent on the scope settings. The Short setting will set the record length to 1M.

Looks like a typo, did a quick test with short memory mode:

Set to 500 ns/div-> samples at 200 MSa/s

(500 ns/div) x (10 div) x (200 MSa/s) = (5 us)(200 MSa/s) = 1000 Sa
« Last Edit: June 01, 2013, 07:16:03 am by mike1305 »
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #113 on: June 01, 2013, 07:13:02 am »
Wouldn't be surprised if the manual had a typo. It's 1,000 points, I can guarantee it. Did some testing on sample rate at various timebases. There is no way they are using 1M points of memory at 200ns/div and getting 80k wfm/s performance.

It would be more than a typo - it would be multiple typos - no where in the manual does it mention 1k. I think it's 1M (500k with 2 channels), which would be rather standard these days.

« Last Edit: June 03, 2013, 09:25:30 am by marmad »
 

Offline mike1305

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #114 on: June 01, 2013, 07:17:20 am »
Wow, I wonder where they get that from. What's the point of "short" memory that's only half the depth? Why not just turn on channel 2 to half the memory depth?  :-//

Also, check my edit above. Perhaps Dave can verify when he does a full review/comparo, I may just be going bonkers!  :-BROKE
« Last Edit: June 01, 2013, 07:21:03 am by mike1305 »
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #115 on: June 01, 2013, 07:32:43 am »
Wow, I wonder where they get that from. What's the point of "short" memory that's only half the depth? Why not just turn on channel 2 to half the memory depth?  :-//

Also, check my edit above. Perhaps Dave can verify when he does a full review/comparo, I may just be going bonkers!  :-BROKE

500ns/div with just a single channel on has a sampling rate of 200MSa/a? Yes, you must be right - SHORT must be 1k - and AUTO must give you the 1M - and it must be a typo on the page before the table I posted. I guess it makes more sense since 'SHORT' seemed like an odd thing to call 1M.

Edit: That means in Dave's vid - if he actually had the 'SHORT' selected - he was sampling at 500kSa/s! No wonder he got the glitches! ;D
« Last Edit: June 04, 2013, 09:34:13 pm by marmad »
 

Offline Hydrawerk

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #116 on: June 01, 2013, 09:03:09 am »
And the GDS-806C from 2004 or so has this funny memory... It was sometimes 125kpoints and sometimes 0,5kpoints.  :-DD :-DD
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Offline Yaksaredabomb

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #117 on: June 04, 2013, 01:33:39 pm »
...Perhaps Dave can verify when he does a full review/comparo....

That would be neat to see, an update and compare after some time with the manual and with Instek's comments.  Hope it works out - even if it has to be less than an hour to allow Dave to create it in a reasonable time.  (though I side with the "longer, less-edited, unscripted" crowd)
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Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #118 on: June 04, 2013, 09:26:29 pm »
...Perhaps Dave can verify when he does a full review/comparo....

That would be neat to see, an update and compare after some time with the manual and with Instek's comments.  Hope it works out - even if it has to be less than an hour to allow Dave to create it in a reasonable time.  (though I side with the "longer, less-edited, unscripted" crowd)
As mentioned in the other thread, the 1k Short record length is already confirmed in the video this thread is attached to (check rate divided-by timebase between 53:20 - 53:40) - and also in the Instek's FW HELP files. I'm not sure if any further comments from Instek will be forthcoming - or from Dave is really necessary.

I wouldn't mind seeing someone measure the waveform update rates of the Instek at the AUTO (1M) settings which produce the 2GSa/s rate (not the ETS rates) - for a more realistic speed comparison against the Rigol DS2000 (for which I've posted the numbers below) - but I doubt Dave has time for that - and Greg doesn't seem to be posting much info any more.
« Last Edit: June 04, 2013, 09:37:26 pm by marmad »
 

Offline grego

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #119 on: June 04, 2013, 10:18:03 pm »
Greg is busy with work and travel lately.  Sorry. :(  Calms back down in a couple of weeks.
 

Offline Yaksaredabomb

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #120 on: June 05, 2013, 03:22:37 am »
Greg is busy with work and travel lately.  Sorry. :(  Calms back down in a couple of weeks.

That's alright.  We'll be excited to have you back though!
 
More time with the LA decode functions would be another nice thing.  Seems like they could be better than nothing but not much more.  I seem to remember reading they're not nearly as nice/useful/refined as the Rigol and Agilent decode options, but don't quote me on that.
 
Edit June 6th: My display name has recently changed from "jneumann" to "Yaksaredabomb"
« Last Edit: June 06, 2013, 11:35:20 pm by Yaksaredabomb »
My display name changed June 6th from "jneumann" to "Yaksaredabomb"
 

Offline grego

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #121 on: June 05, 2013, 08:32:46 am »
As a side note, got a note back from Instek:

Quote
I have spoken to our factory engineers, and you are correct. There was an error on the user manual. The memory is 1K points. I had them update the user manual, and it has been uploaded on the website. I sincerely apologize for the error, it was not our intention to mislead the consumer. If you have any further questions, please call or email me.

Moderately annoying since it was one of the things I was looking at when I was evaluating.
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #122 on: June 05, 2013, 08:47:37 am »
As a side note, got a note back from Instek:

Quote
I have spoken to our factory engineers, and you are correct. There was an error on the user manual. The memory is 1K points. I had them update the user manual, and it has been uploaded on the website. I sincerely apologize for the error, it was not our intention to mislead the consumer. If you have any further questions, please call or email me.

Moderately annoying since it was one of the things I was looking at when I was evaluating.

Strange that the Help screen from the DSO is also incorrect - but with a different number (meaning for 2 channels?)
 

Offline Hydrawerk

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #123 on: June 05, 2013, 09:13:45 am »
OK, this table is for 1kpoints per channel.

Now what is it like for Auto record length?
Definitely this scope is worse than Rigol DS2000 and Agilent DSOX2000 at waveform update rate. Now how does the table change when you turn on all channels, FFT or logic analyzer? ???
DS2000 must be better when it has two FPGAs.
Here is the Rigol chart. http://www.eevblog.com/forum/testgear/first-impressions-and-review-of-the-rigol-ds2072-ds2000-series-dso/?action=dlattach;attach=32606
It has up to 50 000 waveforms per second at 14kpoints per channel...
« Last Edit: June 05, 2013, 09:21:04 am by Hydrawerk »
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Offline Hydrawerk

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #124 on: June 05, 2013, 09:23:38 am »
Here's another Marmad's table for DS2000.
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Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #125 on: June 05, 2013, 10:20:46 am »
The thing that's a bit of a pity is that there are many nice features of this DSO - but either through some intentional or unintentional blunders, Instek has made it much more difficult to focus on those things.

Setting aside the mess-up with the published information of the Short record length, I don't think they should have pushed the 80k wfrm/s rate (with the reduced sample rate) as their banner rate - they should have just stated clearly that it can do ~50k wfrm/s  w/1k @ 2GSa/s - and it can get as high as 80k at lower sample rates - which is totally fine in the price class. The same with the intensity grading - why not just publish the actual specifications? It's not as good as the Rigol or Agilent, but it's better than the lower cost DSOs - and you get other features in exchange.

But the perception, intended or not, of being either a little misleading or reticent with some of the information - is, IMO, worse than just honestly stating from the start, "Here are all the specs: both the strong and weak points."
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #126 on: June 05, 2013, 10:28:52 am »
Moderately annoying since it was one of the things I was looking at when I was evaluating.

BTW, Greg, I suspect you might be able to turn that 'annoyance' into some kind of tangible 'settlement' from Instek (while pointing out that even their FW Help information was misleading).
 

Offline Hydrawerk

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #127 on: June 05, 2013, 11:05:02 am »
I am not a Rigol fan, but I think that there was no critical error in their manual or specifications of DS2000. There was clearly stated when the waveform update rate reaches 50000.
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Offline Yaksaredabomb

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #128 on: June 05, 2013, 04:30:20 pm »
OK, this table is for 1kpoints per channel.
...
Now what is it like for Auto record length?
I'd be curious to see the auto record length chart, too.  Please post a link or the info itself if anyone has it.
 
Edit June 6th: My display name has recently changed from "jneumann" to "Yaksaredabomb"
« Last Edit: June 06, 2013, 10:37:51 pm by Yaksaredabomb »
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Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #129 on: June 05, 2013, 08:32:11 pm »
OK, this table is for 1kpoints per channel.
...
Now what is it like for Auto record length?
I'd be curious to see the auto record length chart, too.  Please post a link or the info itself if anyone has it.

No one does.
 

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #130 on: June 05, 2013, 08:56:06 pm »
DS2000 must be better when it has two FPGAs.

the amount of FPGA is from pure technical point of view not really important, you can have one bigger FPGA doing
the job better that 3 other small FPGAs.

In case on Instek (who is using Altera FPGAs since 5+ yrs), they picked up high pin count Cyclone IV instead of
two smaller Spartan 6 like Rigol did. A high pin count Spartan 6 costs more money, Xilinx license costs as well
money (and not to forget IPs).

We would need to see design sources to judge about which DSO is better (from FPGA vs. design point of view).

For the use of DSO there are other things that important, but not pin count or size or amount of FPGA, etc.
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Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #131 on: June 05, 2013, 09:34:17 pm »
We would need to see design sources to judge about which DSO is better (from FPGA vs. design point of view).

Well, I think we can draw some conclusions about the power/speed of each approach from the fact that the Instek uses a 1k sample length for it's high wfrm/s, the low number of levels of it's intensity grading, and from the evidence provided in Dave's video of the display updating freezing and stuttering. These are all tangible byproducts of their design.
 

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #132 on: June 05, 2013, 10:39:55 pm »
To clarify:

 

Offline grego

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #133 on: June 06, 2013, 04:08:51 am »
Moderately annoying since it was one of the things I was looking at when I was evaluating.

BTW, Greg, I suspect you might be able to turn that 'annoyance' into some kind of tangible 'settlement' from Instek (while pointing out that even their FW Help information was misleading).

I'm working on that now.
 

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #134 on: June 06, 2013, 06:10:16 am »
To clarify:

ehm, these 656600000 wfms/s at 20ns/DIV on Rigol, where they coming from  :-//

yeah, i see it now, somehow i saw on right side (Instek) max 81 330 (where you wrote 81 330 000)
which was like "wfms/s" result and on left side trilions of milions :)
« Last Edit: June 06, 2013, 07:05:33 am by tinhead »
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Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #135 on: June 06, 2013, 06:28:58 am »
ehm, these 656600000 wfms/s at 20ns/DIV on Rigol, where they coming from

Wfrm/s? As it states, it's total samples captured per second (with the DSO's fastest sample length): @20ns/div, it's ~46,900 acquisitions * 14k = 656.6M samples per second.**

For the Rigol, it's the wfrm/s * 14k; for the Instek, it's wfrm/s * 1k.

** = Hypothetical (see post below)
« Last Edit: June 06, 2013, 08:23:02 am by marmad »
 

Offline Hydrawerk

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #136 on: June 06, 2013, 06:54:22 am »
EDIT: I am not sure about this.

At DSOX2002A you get up to 50 000 wfrms/s ×50kpoints = 2.5×10^9 =
2 500 000 000 total samples captured per second.  :-+
(Yes, the memory length is not great.)
« Last Edit: June 07, 2013, 12:29:51 am by Hydrawerk »
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Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #137 on: June 06, 2013, 07:32:27 am »
At DSOX2002A you get up to 50 000 wfrms/s ×50kpoints = 2.5×10^9 =
2 500 000 000 total samples captured per second.

Well, we were discussing what 2 FPGAs vs. 1 FPGA might mean in terms of acquisition throughput - not really ASICs. But yes, the Agilent is the fastest, although I've never seen any published numbers yet for the wfrm/s when using the 1M (or is it 500k?) added memory.
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #138 on: June 06, 2013, 08:20:17 am »
At DSOX2002A you get up to 50 000 wfrms/s ×50kpoints = 2.5×10^9 =
2 500 000 000 total samples captured per second.

Actually, after thinking about it more, it's impossible that the Agilent ever captures that much data (see below). Below 500ns on the Rigol or Agilent (or 50ns on the Instek), there is no way of really knowing exactly what the DSO is doing about the excess (offscreen) samples. I mean, if you STOP the DSO and zoom out, the full sample size is there - but what it does precisely while in RUN mode is unknown. My total samples chart is just hypothetical (and likely wrong) at those smaller time base settings because the DSOs quite possibly (in some cases, they absolutely must) limit the acquisition size until stopped.

For a good example, what would the Agilent 3000 X-Series do? At 10ns/div, it's supposed to do 1,030,000 wfrm/s. But it can't possibly be acquiring the fixed memory size (1M) - it's impossible because (1 / 4G[Sa/s]) * 1M[Pts] * 1.03M[wfrms] = 257.5 seconds. In fact, it must only be acquiring a tiny subset of the full memory (possibly just the amount of samples for the display) - and only capturing the full length when STOP is pushed.
« Last Edit: June 06, 2013, 10:01:03 am by marmad »
 

Offline Hydrawerk

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #139 on: June 06, 2013, 09:18:49 am »
Well, we were discussing what 2 FPGAs vs. 1 FPGA might mean in terms of acquisition throughput - not really ASICs. But yes, the Agilent is the fastest, although I've never seen any published numbers yet for the wfrm/s when using the 1M (or is it 500k?) added memory.
I tried it. At Run/Stop mode DSOX2002A uses 500kpoints memory per channel (when one or all channels used.) The Trig Out frequency is as specified by Agilent in their PDF (up to 50 000 kHz). http://cp.literature.agilent.com/litweb/pdf/5989-7885EN.pdf
I measured it.
Well, DSOX2000 is as fast as possible... so you cannot set the memory length, interpolation or even dots/vectors.  :palm: No scope is perfect.
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Offline Hydrawerk

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #140 on: June 06, 2013, 09:34:08 am »
At DSOX2002A you get up to 50 000 wfrms/s ×50kpoints = 2.5×10^9 =
2 500 000 000 total samples captured per second.

For a good example, what would the Agilent 3000 X-Series do? At 10ns/div, it's supposed to do 1,030,000 wfrm/s. But it can't possibly be acquiring the fixed memory size (1M) - it's impossible because (1 / 4G[Sa/s]) * 1M[Pts] * 1.03M[wfrms] = 257.5 seconds. In fact, it must only be acquiring a tiny subset of the full memory (possibly just the amount of samples for the display) - and only capturing the full length when STOP is pushed.
Yes, at 10ns/div timebase you will never see the whole record on the screen. (The picture is as Sagan would draw it.  :) :)  )

DSOX2002A triggers 50 000 times in a second, but the whole record update rate might be much lower.
« Last Edit: June 06, 2013, 09:37:57 am by Hydrawerk »
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Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #141 on: June 06, 2013, 09:43:44 am »
I tried it. At Run/Stop mode DSOX2002A uses 500kpoints memory per channel (when one or all channels used.) The Trig Out frequency is as specified by Agilent in their PDF (up to 50 000 kHz). I measured it.

Yes, at 10ns/div timebase you will never see the whole record on the screen.

You miss my point. It has nothing to do with what you see on the screen - the DSO can't capture that much data in the given time. Your DSOX2002A can't capture 500k samples 50,000 times a second - it's impossible: at 2GSa/s, it takes the DSO 250us to fill 500k; if you multiply 250us * 54k you get 13.5 seconds.

Your DSO (and the Agilent 3000 X models) must be capturing MUCH less than 500k - and only filling the full memory on the FINAL capture - when stopped.

In fact, it's an impossibility that the 2000 X-Series is EVER capturing 50k at any time base setting below 200ns/div, because if the wfrm/s rate is > 50k the total acquire time > 1s. Again - impossible.
« Last Edit: June 06, 2013, 09:59:51 am by marmad »
 

Offline Hydrawerk

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #142 on: June 06, 2013, 09:53:10 am »
Well, only Agilent guys know how their scope really works. Thats it... On the other hand, one sales manager from czech distributor of Agilent knew a shit. He told me, that DSOX2000 has a real 230V switch.  He told me that he even replaced one of them. :-DD :-DD :-DD But we know that.
Even my scope consumes 5 Watts when turned off. I have a 230V wattmeter.
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Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #143 on: June 06, 2013, 09:56:06 am »
Well, only Agilent guys know how their scope really works. Thats it...

What I'm describing is math - the Agilent DSOs MUST shorten their acquire length in order to achieve the wfrm/s rates - it's a simple fact, easily proved with the numbers.
 

Offline Hydrawerk

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #144 on: June 06, 2013, 10:54:29 am »
OK
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Offline tinhead

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #145 on: June 06, 2013, 08:07:14 pm »
For a good example, what would the Agilent 3000 X-Series do? At 10ns/div, it's supposed to do 1,030,000 wfrm/s. But it can't possibly be acquiring the fixed memory size (1M) - it's impossible because (1 / 4G[Sa/s]) * 1M[Pts] * 1.03M[wfrms] = 257.5 seconds. In fact, it must only be acquiring a tiny subset of the full memory (possibly just the amount of samples for the display) -

1 * samples * wfms/s / samples/s = second ? i need koffee ^^

At 4GS/s sample rate and 1Mpoint buffer depth the DSO need 250us to capture data into memory, then it need
to do the postprocessing. The total acquisition time is sum of both (i'm writing down all steps for those who get lost).
But total time is 1us (at 1M wfms/s), so the postprocessing need to be smaller than that, at least twice that small
(assuming Megazoom IV ASIC can do same data throughput during postprocessing). This give us 2000 data point per wfms.
Now let's calculate back, these 2000 points sampled with 4GS/s at 1M wfms/s give us then 0.5 which is less than
a second, which is what it should be because it need to be "per second".

The real data point value is probably equal to display resolution (visible area size, is it 600 dots?).

and only capturing the full length when STOP is pushed.

right, when writing once the full 1M buffer there is no blind time, so this part can work like that.

It can be as well as on TEK DPOs (not sure if on latest model as well), where the buffer is one time fully written
at begin of sampling (so when you do single shot it is once, and when you do RUN it is once ++++) and then
refreshed with what the hardware allows at max. (e.g. DPO3000 with 10k point, TDS700 with 500point)
 
When that's the case for Agilent, you would not even see (even with 4M memory) any gap between
"button pushed vs. data displayed", that' only 1ms to get full buffer once sampled, the refresh
data with 600-2000 dots per wfms is sufficient (as you can anyway see only that data and nothing else on screen).

So Rigol DS2000, with 21us total acquisition time from which 7us is used to capture the 14k points is not that bad,
that's (worst case) 7 time the buffer size of Agilent DSOX3000 (based on the findings/calculations above),
that's worst case third of DSOX 3000 wfms/s rate ^^ yeah, maybe.
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Offline EEVblog

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #146 on: June 06, 2013, 08:28:13 pm »
Well, DSOX2000 is as fast as possible... so you cannot set the memory length, interpolation or even dots/vectors.  :palm: No scope is perfect.

The dots/vectors thing aside, isn't the Agilent essentially "perfect" in this case?
i.e. it automatically selects whatever memory it needs to get blindingly fast update rate in run mode, and then gives full memory in stop mode when you want to analyse it, right?
After all, you really only care about memory after you've stopped it and want to analyse it. Because features like Hires mode, and peak detect mode are things that work independent of memory depth, so essentially there is no benefit to having a deep memory while in run mode.
It obviously might operate different (and slow down?) in dual timebase zoom mode?
But if I'm not in dual timebase mode, and only have limited data on screen, then any extra deep memory being captured in run mode is essentially being wasted and is just slowing down the update rate, so it's pointless tradeoff. Update rate would win every time in normal run mode, there is no usage case were deep memory would be an advantage in run mode.
« Last Edit: June 06, 2013, 08:31:54 pm by EEVblog »
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #147 on: June 06, 2013, 08:30:01 pm »
1 * samples * wfms/s / samples/s = second ? i need koffee ^^

 ;D  Perhaps my formula is written a little strange, but it means (1 / 4,000,000,000) * 1,000,000 * 1,030,000  - which basically means it takes 257.5 seconds to fill a 1M buffer 1.03M times (without adding in postprocessing time).

Quote
The real data point value is probably equal to display resolution (visible area size, is it 600 dots?).

Yes, that would be my guess.

Quote
It can be as well as on TEK DPOs (not sure if on latest model as well), where the buffer is one time fully written
at begin of sampling (so when you do single shot it is once, and when you do RUN it is once ++++) and then
refreshed with what the hardware allows at max. (e.g. DPO3000 with 10k point, TDS700 with 500point)

This makes sense - with an added one when STOP is pushed for the last data:  once++.....+++once
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #148 on: June 06, 2013, 09:03:45 pm »
The dots/vectors thing aside, isn't the Agilent essentially "perfect" in this case?
i.e. it automatically selects whatever memory it needs to get blindingly fast update rate in run mode, and then gives full memory in stop mode when you want to analyse it, right?

In some ways, I would say yes. But aside from the fact that (if an Agilent owner) I would just prefer to be able to turn this feature on and off (as with interpolation), some of the results of their method seem a bit questionable to me (although granted only under certain circumstances). The problem with 'automatic' features in complex technology is that if they're not extremely well-documented (in terms of the ramifications on all related sub-systems), the trade-offs are often not clear.

For example, what does the ASIC do exactly when I want my trigger position 5 divisions to the left of the screen edge? Or what does it do exactly with segments: does it capture them at the fastest speed possible while cutting down the sample length - or does it maintain the sample length while reducing it's update rate?
 

Offline jpb

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #149 on: June 06, 2013, 10:52:04 pm »
The dots/vectors thing aside, isn't the Agilent essentially "perfect" in this case?
i.e. it automatically selects whatever memory it needs to get blindingly fast update rate in run mode, and then gives full memory in stop mode when you want to analyse it, right?

In some ways, I would say yes. But aside from the fact that (if an Agilent owner) I would just prefer to be able to turn this feature on and off (as with interpolation), some of the results of their method seem a bit questionable to me (although granted only under certain circumstances). The problem with 'automatic' features in complex technology is that if they're not extremely well-documented (in terms of the ramifications on all related sub-systems), the trade-offs are often not clear.

For example, what does the ASIC do exactly when I want my trigger position 5 divisions to the left of the screen edge? Or what does it do exactly with segments: does it capture them at the fastest speed possible while cutting down the sample length - or does it maintain the sample length while reducing it's update rate?

I think that they define this quite well in their manuals, particularly for the 5000/6000/7000 series :

Memory Depth/Record Length
[Run/Stop] versus [Single]
When the oscilloscope is running, the trigger processing and update rate are optimized over the memory depth.
Single
Single acquisitions always use the maximum memory available—at least twice as much memory as acquisitions captured in Run mode—and the oscilloscope stores at least twice as many samples. At slow sweep speeds, the oscilloscope operates at a higher sample rate when Single is used to capture an acquisition due to the increased memory available. To acquire data with the longest possible record length, press the [Single] key.
Running
When running, versus taking a single acquisition, the memory is divided in half. This allows the acquisition system to acquire one record while processing the previous acquisition, dramatically improving the number of waveforms per second processed by the oscilloscope. While running, maximizing the rate at which waveforms are drawn on the display provides the best representation of your input signal.

So the optimisation is really just between splitting the memory into two buffers for rapid waveform running mode or using it all as one buffer for single shot mode.

Elsewhere in the manual it explains that they have a pre-trigger buffer which is FIFO and which they fill before looking for the trigger event. Then they have the post trigger buffer. They always fill at the maximum sample rate and reduce it by decimation for slower sampling rates. For segmented memory they treat each segment in the same way (pre-trigger and post-trigger buffer). It lists the reset time after each segment as 1microsecond for the 3000X series so the update time will be 2MB at 2GS/s or 1microsec plus an extra microsec which presumably reduces it the wfm/s rate from around 1M to 500K.
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #150 on: June 06, 2013, 11:11:55 pm »
Elsewhere in the manual it explains that they have a pre-trigger buffer which is FIFO and which they fill before looking for the trigger event. Then they have the post trigger buffer. They always fill at the maximum sample rate and reduce it by decimation for slower sampling rates.

So for example, on an Agilent 3000X, given 1M wfrm/s @ 10ns/div, if I move my trigger position to -10 divs, does my wfrm/s drop to 750k - or 500k - or stay the same?

Quote
For segmented memory they treat each segment in the same way (pre-trigger and post-trigger buffer). It lists the reset time after each segment as 1microsecond for the 3000X series so the update time will be 2MB at 2GS/s or 1microsec plus an extra microsec which presumably reduces it the wfm/s rate from around 1M to 500K.

As soon as I spotted the word 'presumably', it made me wonder exactly how you define 'quite well'.  ;)
 

Offline EEVblog

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #151 on: June 06, 2013, 11:35:12 pm »
In some ways, I would say yes. But aside from the fact that (if an Agilent owner) I would just prefer to be able to turn this feature on and off

Why?
Please cite a case were you would need to sacrifice update rate for deep memory in run mode.

Quote
The problem with 'automatic' features in complex technology is that if they're not extremely well-documented (in terms of the ramifications on all related sub-systems), the trade-offs are often not clear.

Agreed. But in this case I am claiming that there is no downside to what Agilent have done here.

Quote
For example, what does the ASIC do exactly when I want my trigger position 5 divisions to the left of the screen edge?

Depends on the type of trigger. In some cases the trigger can be entirely independent of same rate etc.

Quote
Or what does it do exactly with segments: does it capture them at the fastest speed possible while cutting down the sample length - or does it maintain the sample length while reducing it's update rate?

It must capture them at the maximum memory depth, because these are effectively multiple "stop" captures, not simply run mode screen updating.
Agilent know you want to capture and investigate these captured segmented data, so they use all the memory they can. Update rate might be dependent upon trigger type.
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #152 on: June 07, 2013, 12:00:01 am »
Why?
Please cite a case were you would need to sacrifice update rate for deep memory in run mode.
Never - assuming the technology worked 100% perfectly 100% of the time. And I know you don't think this kind of result is important, but it is to me. Again, it's fine if you know that this is possible given the Agilent technology and certain settings - and can shut it off. Otherwise it's problematic.

Quote
Agreed. But in this case I am claiming that there is no downside to what Agilent have done here.
I think the automatic adjustment of sample size to maximize wfrm/s is a great idea - but considering that it can occasionally produce, IMO, unwanted artifacts - coupled with the fact that it imposes some conditions on you (such as constant interpolation) - means I'd just like to be able to turn it on and off if desired.

Quote
It must capture them at the maximum memory depth, because these are effectively multiple "stop" captures, not simply run mode screen updating.
Agilent know you want to capture and investigate these captured segmented data, so they use all the memory they can. Update rate might be dependent upon trigger type.
Got it - thanks for the clarifications.
 

Offline EEVblog

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #153 on: June 07, 2013, 12:09:10 am »
Never - assuming the technology worked 100% perfectly 100% of the time. And I know you don't think this kind of result is important, but it is to me. Again, it's fine if you know that this is possible given the Agilent technology and certain settings - and can shut it off. Otherwise it's problematic.

I was talking about apart from the dot/vector & interpolation thing. I do not disagree with you here.

Quote
coupled with the fact that it imposes some conditions on you (such as constant interpolation)

The interpolation is not really related to the automatic memory depth/update rate thing we are talking about, it's simply a separate decision agilent made.
Just because they both can't be changed by the user does not mean they are related.
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #154 on: June 07, 2013, 12:18:55 am »
The interpolation is not really related to the automatic memory depth/update rate thing we are talking about, it's simply a separate decision agilent made.
Just because they both can't be changed by the user does not mean they are related.

Technically true, but the scopes perform the sin(x)/x interpolation in DSP hardware, which is part of the scope’s MegaZoom ASIC - helping to achieve the speeds they get. So I don't know how much it would affect the functioning - or alter the wfrm/s rates - if the processes were separated (although I wish they were).

BTW, I threw together a spreadsheet based on Agilent's published wfrm/s rates for the X2000 and X3000 - which estimates likely sample sizes and blind times for the different time bases. It should be interesting for X-Series owners. Note: the X2000 is faster than the X3000 at 7 time base settings.

« Last Edit: June 07, 2013, 02:17:49 am by marmad »
 

Offline jpb

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #155 on: June 07, 2013, 12:48:40 am »
So for example, on an Agilent 3000X, given 1M wfrm/s @ 10ns/div, if I move my trigger position to -10 divs, does my wfrm/s drop to 750k - or 500k - or stay the same?
It always captures the same amount of memory so the trigger position shouldn't make any difference. It might cause it to vary the relative sizes of the pre-trigger and post-trigger buffers.

The pan and zoom options are only available on the last captured trace and presumably this is captured after you press stop and uses the full memory depth (i.e. not split into two buffers).

I think the idea that it optimizes its memory use for rapid capture is misleading - it just splits the memory in two when in run mode - there is no optimization for different triggers or time bases or anything like that.

The only issue with it might be aliasing at slower timebases because you've only got half the memory but if the capture that is displayed when you press stop uses the full memory (the last trace) you will see the correct waveform at that point anyway.

I think this is a rather different issue to whether or not different interpolations can be turned off.
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #156 on: June 07, 2013, 01:08:49 am »
It always captures the same amount of memory so the trigger position shouldn't make any difference. It might cause it to vary the relative sizes of the pre-trigger and post-trigger buffers.

The pan and zoom options are only available on the last captured trace and presumably this is captured after you press stop and uses the full memory depth (i.e. not split into two buffers).

I think the idea that it optimizes its memory use for rapid capture is misleading - it just splits the memory in two when in run mode - there is no optimization for different triggers or time bases or anything like that.

Sorry, jpb, but I get the impression you haven't read the other posts in the thread - and perhaps that's why you think that Agilent 'define this quite well in their manuals.'  ;)  Of course it optimizes the memory - it's not using the full size of the sample length split in half - this is obvious by simple math. Please read the previous post(s) describing the impossibility of capturing the full half-length given the wfrm/s - and look at the spreadsheet above. Then we can continue the discussion if you like.
« Last Edit: June 07, 2013, 01:16:26 am by marmad »
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #157 on: June 07, 2013, 01:42:14 am »
Never - assuming the technology worked 100% perfectly 100% of the time. And I know you don't think this kind of result is important, but it is to me. Again, it's fine if you know that this is possible given the Agilent technology and certain settings - and can shut it off. Otherwise it's problematic.
I was talking about apart from the dot/vector & interpolation thing. I do not disagree with you here.

I think this is a rather different issue to whether or not different interpolations can be turned off.
What I'm referring to above is not the interpolation issue (even though, yes, I think it would be good to be able to switch it off), it's about the locations of the actual sampled points. In the attached image, the Agilent is clearly doing linear interpolation, and I've marked where the sample points must be - but many of them are nowhere near the correct positions for a perfectly stable, real-time sampled sine wave - regardless of under-sampling. Compare it against another 5MHz sine wave captured with the exact same sampling rate on the Rigol. Perhaps the Agilent is also limiting based on sample rate?

Anyway, this has drifted way off-topic -- so sorry about that.
« Last Edit: June 07, 2013, 02:30:37 am by marmad »
 

Offline jpb

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #158 on: June 07, 2013, 03:34:59 am »
It always captures the same amount of memory so the trigger position shouldn't make any difference. It might cause it to vary the relative sizes of the pre-trigger and post-trigger buffers.

The pan and zoom options are only available on the last captured trace and presumably this is captured after you press stop and uses the full memory depth (i.e. not split into two buffers).

I think the idea that it optimizes its memory use for rapid capture is misleading - it just splits the memory in two when in run mode - there is no optimization for different triggers or time bases or anything like that.

Sorry, jpb, but I get the impression you haven't read the other posts in the thread - and perhaps that's why you think that Agilent 'define this quite well in their manuals.'  ;)  Of course it optimizes the memory - it's not using the full size of the sample length split in half - this is obvious by simple math. Please read the previous post(s) describing the impossibility of capturing the full half-length given the wfrm/s - and look at the spreadsheet above. Then we can continue the discussion if you like.

Presumably it doesn't capture memory that is not visible. It is not really optimization any more than standard oscilloscopes. It splits the memory into two buffers to allow one to be filled whilst the other is processed. Each buffer is split into pre-trigger and post-trigger buffers and it fills the pre-trigger buffer until it gets to the point where it is looking for a trigger (normally half a screen worth), while looking for the trigger the pre-trigger buffer is continuously filled with oldest points removed if there is no space. Once the trigger happens the post-trigger buffer is filled to the point of end of the display.

This all seems reasonably straight forward and is stated in the manual. It is only the last capture, the one you look at, that fills the whole memory as one buffer to allow panning and zooming.

So in your example of 10nsec/div the pre-trigger buffer only fills up to 200 points (for 5 divisions at 4GS/s). So yes, I agree it is much less than 1M or even 250k, but I don't think this is optimization anymore than my WaveJet optimises its memory when it does a similar thing (but rather more slowly ;)).

The unusual feature is the last capture which does fill the memory but this doesn't affect the wfm/s.
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #159 on: June 07, 2013, 04:06:25 am »
Presumably it doesn't capture memory that is not visible.

Presumed by who? If you presume ALL DSOs only capture sample memory that is visible on the display at all times you're terribly wrong. They don't all operate like your WaveJet.  ;)
 
And I know what's written in the manual and extra Agilent literature quite well - but I don't feel like arguing about semantics; I'm more interested in the reasons behind my previous post.
« Last Edit: June 07, 2013, 04:19:32 am by marmad »
 

Offline jahonen

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #160 on: June 07, 2013, 04:26:24 am »
Those sample points are probably altered by the anti-alias algorithm. I did a test with my Agilent MSO6034A, which has an option to turn anti-aliasing on and off. It seems that the sine becomes "noisy" when anti-alias is turned on. Too bad that they have removed that option to turn aa off in newer MegaZoom generation.

But I must say that I have never noticed that, or any measurement hasn't gone wrong in past 8 years or so that I have used that Agilent. Working anti-alias has been quite good trade-off.

Regards,
Janne
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #161 on: June 07, 2013, 04:29:03 am »
Those sample points are probably altered by the anti-alias algorithm. I did a test with my Agilent MSO6034A, which has an option to turn anti-aliasing on and off. It seems that the sine becomes "noisy" when anti-alias is turned on. Too bad that they have removed that option to turn aa off in newer MegaZoom generation.

But I must say that I have never noticed that, or any measurement hasn't gone wrong in past 8 years or so that I have used that Agilent. Working anti-alias has been quite good trade-off.

Regards,
Janne

Thanks for the clarification, Janne - very informative! So it seems a pity they didn't leave anti-aliasing, as well as interpolation, as switchable options. I wonder precisely why that's happening? I couldn't replicate the error on my Rigol using anti-aliasing at those sample rates.
« Last Edit: June 07, 2013, 04:34:23 am by marmad »
 

Offline jpb

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #162 on: June 07, 2013, 04:46:25 am »
Presumably it doesn't capture memory that is not visible.

Presumed by who? If you presume ALL DSOs only capture sample memory that is visible on the display at all times you're terribly wrong. They don't all operate like your WaveJet.  ;)
 
And I know what's written in the manual and extra Agilent literature quite well - but I don't feel like arguing about semantics; I'm more interested in the reasons behind my previous post.
Fair enough, I too don't particularly want to get into an argument about a scope I don't even have. My presumption was only that since there is no option to look at points outside the visible window (you can only pan and zoom on the last capture, at least that is what the manual states) it would make no sense to capture such data. This is a different situation to say segmentation where you can look at the saved history.

Almost all the points of discussion so far seem to involve data that is stored (such as the interpolation used on points that are zoomed in on), whilst the high waveforms per second data is differently captured on the Agilent - only one set is captured in detail presumably when you press the stop button. So whilst it is running it is capturing the minimum of data at a fast rate, when you stop it to look at the results it does a completely different sort of capture which will be much slower and more detailed but as there is only one of it this it doesn't matter. (Assuming the time base is fast enough for such a capture to be well under a second.)
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #163 on: June 07, 2013, 05:08:44 am »
Almost all the points of discussion so far seem to involve data that is stored (such as the interpolation used on points that are zoomed in on), whilst the high waveforms per second data is differently captured on the Agilent - only one set is captured in detail presumably when you press the stop button. So whilst it is running it is capturing the minimum of data at a fast rate, when you stop it to look at the results it does a completely different sort of capture which will be much slower and more detailed but as there is only one of it this it doesn't matter. (Assuming the time base is fast enough for such a capture to be well under a second.)

Right - that's what we've been getting at - although tinhead added that the first capture might fill the buffer as well. So it might look something like:
(RUN)FULL/DISPLAY/DISPLAY/DISPLAY...DISPLAY/DISPLAY/DISPLAY(STOP)/FULL

I think it's a clever scheme, but I'm not sure this is explicitly spelled-out in the literature - especially since some DSOs capture the full record length over and over again - even when it's larger than the display window.
 

Offline grego

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #164 on: June 07, 2013, 05:12:57 am »
BTW folks I recently spoke to tequipment.net and Instek and I am RMA'ing my GDS2204A and the LA module.  Unfortunately the errors in the printed specs affected my purchase decision so I made the decision to try to do a return.

Please note this does not mean I don't like the scope - I do - I just personally made a purchase decision based on erroneous data and didn't want to be held to that as it would cause me issues down the road.
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #165 on: June 07, 2013, 05:15:20 am »
Greg, any final thoughts on the LA module and decode options? I think a number of people were curious to hear information/opinions about that.
« Last Edit: June 07, 2013, 05:21:56 am by marmad »
 

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #166 on: June 07, 2013, 05:47:37 am »
Speaking of tequipment.net, I just noticed that they've cut the prices on the entire GDS-2000A series (and all of the accessories and options) by 15%. With the 5OFF coupon code, that means 20% off total.
 

Offline grego

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #167 on: June 07, 2013, 05:56:17 am »
Greg, any final thoughts on the LA module and decode options? I think a number of people were curious to hear information/opinions about that.

Not really - it worked like any other MSO LA to be honest.  I didn't use it a ton as I was waiting for the firmware update to enable CAN decodes but it was fine - basically what I wanted spec wise and seemed to function as such.  It's a plus that it's there, it works well, and it includes all the decodes with the module purchase.  I'd recommend it for that.  I am just frustrated the published specs don't conform with the expected output based on the published documentation at the time of my purchase decision.
 

Offline Hydrawerk

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #168 on: June 07, 2013, 06:03:04 am »
Well, I didn't expect that you will return your scope... Which scope are you going to buy now? Well, I would wait for the DS2000-S with function generator...
Amazing machines. http://www.youtube.com/user/denha (It is not me...)
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #169 on: June 07, 2013, 06:05:04 am »
Not really - it worked like any other MSO LA to be honest.  I didn't use it a ton as I was waiting for the firmware update to enable CAN decodes but it was fine - basically what I wanted spec wise and seemed to function as such.  It's a plus that it's there, it works well, and it includes all the decodes with the module purchase.  I'd recommend it for that.  I am just frustrated the published specs don't conform with the expected output based on the published documentation at the time of my purchase decision.

Thanks for the update, Greg.

BTW, if any EU members are interested in the DSO, you should seriously consider having it shipped from Tequipment (although I can't attest to dealing internationally with them). Without VAT or shipping, the difference in price, for example, of the GDS-2074A 70MHz 4-channel is:
Tequipment.net = ~€ 913,00
EU Prices           = ~€ 1.165,00

€ 200 buys a lot of shipping - and there's no duty on DSOs. And, of course, you'd save even more if you add any 20%-off options on top of that.
« Last Edit: June 07, 2013, 06:07:07 am by marmad »
 

Offline Hydrawerk

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #170 on: June 07, 2013, 06:06:22 am »
Now it's time for Dave to make more experiments with GDS-2000A. At least the search and place mark function looks good. DS2000 or DSOX2000 have nothing like that!
Amazing machines. http://www.youtube.com/user/denha (It is not me...)
 

Offline grego

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #171 on: June 07, 2013, 06:07:00 am »
Well, I didn't expect that you will return your scope... Which scope are you going to buy now? Well, I would wait for the DS2000-S with function generator...

Probably the new 4000 with MSO option.  But that'll have to wait until I get this RMA processed.
 

Offline Hydrawerk

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #172 on: June 07, 2013, 06:10:37 am »
Well, the DS4000 is a heavy duty scope with extra long memory  :-+ :-+ and large fan, but too expensive for me. Most hobbyists cannot afford one.  :(
« Last Edit: June 07, 2013, 06:13:14 am by Hydrawerk »
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Offline grego

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #173 on: June 07, 2013, 06:26:04 am »
Main thing is I want 4 channels, intensity grading with an MSO option - so we'll see.

And no, I don't want to spend umpty-kajillion-dollars on an Agilent.  I may have more of a budget than the average hobbyist but I'm not THAT rich! :)
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #174 on: June 07, 2013, 08:43:51 am »
Main thing is I want 4 channels, intensity grading with an MSO option - so we'll see.
Some interesting stuff in the data sheet for the upcoming MSO4000 series (if you want to Google Translate Chinese):

Here are some specs for the Digital channels (lots o'memory - up to 28M per channel):

Digital channel sampling rate 1GSa/s, memory depth per channel up to 28Mpts standard
Digital channel waveform capture rate of 85,000 wfms/s
Support hardware real-time digital channel waveform recording, playback, recording a maximum of up to 64,000 frames
Supports analog and digital channels mixed triggering and decode
Convenient digital channel grouping and group operations
Support for multiple logic levels
Time-correlated analog and digital channels are displayed waveform

Real-time sampling rate: Digital channels:  1.0 GSa/s
Peak detection:               Digital channels:  1 ns
Minimum detectable
pulse width:                    Digital Channel: 5 ns
Memory Depth                 Digital channels: Max 28M Point per channel

Threshold:                      8-channel group 1 adjustable threshold
Threshold Selection:       TTL (1.4 V)
                                       5.0 V CMOS (+2.5 V), 3.3 V CMOS (+1.65 V)
                                       2.5 V CMOS (+1.25 V), 1.8 V CMOS (+0.9 V)
                                       ECL (-1.3 V)
                                       PECL (+3.7 V)
                                       LVDS (+1.2 V)
                                       0 V
                                       User-defined
Threshold range:            ± 20.0V, 10 mV steps
Threshold Accuracy:        ± (100 mV + 3% of threshold setting)
Dynamic Range:              ± 10 V + threshold
Minimum voltage swing:  500 mVpp
Vertical resolution:          1 bit
« Last Edit: June 07, 2013, 08:54:02 am by marmad »
 

Offline Hydrawerk

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #175 on: June 07, 2013, 08:45:51 am »
When will it come to market? In December 2013? And does DS4000 have 2GSa/s per each channel?
« Last Edit: June 07, 2013, 08:50:18 am by Hydrawerk »
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Offline grego

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #176 on: June 07, 2013, 11:31:11 pm »
When will it come to market? In December 2013? And does DS4000 have 2GSa/s per each channel?

Per the specs it's 4GSa/s single channel, 2GSa/s dual channel, yes.  Digital channels are 1GSa/s.

In other news I just generated the shipping label on my GDS - it's going back today.  Sorry to see it go - I really wanted it to work out but the incorrect specs really affected the purchasing decision in side-by-side comparisons.
 

Offline Hydrawerk

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #177 on: June 08, 2013, 12:53:42 am »
Well, that's sad... Only few people return their DS2000, because Rigol has a wow factor...
GW Instek scopes are weird. The expensive GDS-3000 from year 2011 had  only WTF 25kpoints per channel.
Amazing machines. http://www.youtube.com/user/denha (It is not me...)
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #178 on: June 08, 2013, 02:48:13 am »
Well, that's sad... Only few people return their DS2000, because Rigol has a wow factor...
GW Instek scopes are weird. The expensive GDS-3000 from year 2011 had  only WTF 25kpoints per channel.

Hell, I returned a Rigol DS1052E, Owon SDS7102, and Hantek DSO5062B - all in the space of about 2 months.  :)  Another reason it's silly to buy this kind of gear from Chinese outlets in order to save a few bucks.
« Last Edit: June 08, 2013, 02:50:07 am by marmad »
 

Offline marmad

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #179 on: June 08, 2013, 03:04:25 am »
Now it's time for Dave to make more experiments with GDS-2000A. At least the search and place mark function looks good. DS2000 or DSOX2000 have nothing like that!
Tequipment.net have made a video demonstrating the Search function on the GW Instek GDS-2000A:




As well as one on the Logic Analyzer:




And on Segmented memory:

 

Offline grego

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #180 on: June 08, 2013, 05:10:06 am »
Those functions all worked really well - like I said I really wanted to like the scope.  It had pretty much all the features I wanted save the "dated" appearance (which isn't a feature per se).  The problem is either by just a fat-finger or in translation the specs didn't match up with reality.  It's unfortunate. :(
 

Offline Computeruser

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #181 on: June 12, 2013, 04:14:03 am »
Well, despite some nay-saying above, I purchased the GW-Instek 2304A and a B&K 5054 25 MHz Function generator to go with it. I only just got the boxes via UPS an hour ago, but all is up and running properly. I am quite happy with the Instek. The style may be dated but it all works fine. A 25Mhz Sine Wave shows up properly. The Square Wave is not very square past 5Mz but they are constant voltage throughout the range which is fine.  <--- Fixed!   The default setup is for high output impedance and I had terminated the cable with a 50 ohm load. I set the B&K to use low output impedance (50 ohm) and now the square wave at 25 MHz is just fine - nice and square and good fast rise time.

The probes are good and BNC connectors are well done. Somebody panned the probes but mine are fine. I have Tektronix 10X probes to compare with and the Instek probes are fine.

So my first impression is that I got a decent machine. Valuetronics sold it to me less than list and threw in the function generator for free. My B&K is better (and note my fix above).

So I retired 2 7000 series scopes, an old HP Function Generator (bad power supply) and my Fluke 8022 digital meter. I got a Fluke 87V and that is a swell meter.

.... C
« Last Edit: June 12, 2013, 12:13:22 pm by Computeruser »
 

Offline Computeruser

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #182 on: June 13, 2013, 09:04:20 am »
Day 2 of the GW-Instek and the B&K 4054.

The GW-Instek still seems like a good oscilloscope to me. It does a lot that the much more expensive Tektronix and Agilent machines do. I was not going to invest more money so I am happy with what I got for the money I spent.

I tried to use the Function Generator today for the first time and it did not work. A quick peek at the manual gave me the reason. The Instek came with Firmware V1.08. The FG needs V1.13. Firmware is nowhere to be found on Instek's (not very good) website. A tech support query brought a very speedy answer with a Drop Box link to V1.15 and the firmware upgrade manual. It is a lengthy process but I have done this before on my Tektronix 2024C. So now the Instek is at firmware V1.15 and the Function Generator works fine.

I made a mistake in the post above. I was looking at the wrong channel on my B&K 4054 when I concluded that the square wave was good at higher speeds. In fact, as you wind up the frequency, you start to see the rise time of the generator (12ns). So past 5 MHz, the square wave appears a bit rounded at the top left corner.

Up to 5 MHz the Instek DS2-FGN and the B&K 4054 are very similar in performance. I am very happy with the Instek Function Generator.

I had some funny little lines in the square wave. I went to Trigger settings and used LF Reject and the signal cleaned up right away. I have used LF Reject on analogue scopes so that is no surprise.

I have unboxed all 4 probes and all 4 came properly compensated. That is no surprise - They are for my particular Instek and all 4 channels are the same. Quality is good and even across all 4 probes and they work well.

Overall, I have not found any reason to regret my purchase.

.... C
 

Offline Hydrawerk

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #183 on: June 13, 2013, 09:48:04 am »
The Instek came with Firmware V1.08. The FG needs V1.13. Firmware is nowhere to be found on Instek's (not very good) website.
:palm: :palm:
firmware upgrade manual. It is a lengthy process but I have done this before on my Tektronix 2024C.
How difficult is it  to upgrade firmware on GDS-2000A??
Amazing machines. http://www.youtube.com/user/denha (It is not me...)
 

Offline Computeruser

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #184 on: June 13, 2013, 09:55:15 am »
You need to read through the Firmware document. For my 2304, I used this link to get the firmware and to get the PDF guide.

 http://jack-gwinstek.blogspot.com/2013/05/gds-2000a-firmware-update-v115.html

My machine was at V1.08 so it was easy (lengthy, but easy). I exploded the firmware onto a USB key, put it in the machine and followed the directions on the Utility button. Basically you find your upgrade file on the key, select it, and the firmware updates. It took about 20 minutes (maybe a bit less) and the initial boot up to 5 minutes or so. Once all done, it operates very normally.

Read the PDF from top to bottom before you start and if you have any questions, contact Instek Support.

... C
 

Offline Hydrawerk

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Re: EEVblog #474 - GW Instek GDS-2000A Series Oscilloscope Unboxing & Fi...
« Reply #185 on: June 13, 2013, 10:31:45 am »
Well, I would expect that that the firmware is located on the manufacturer's website and not here. http://jack-gwinstek.blogspot.cz/search/label/Oscilloscopes
The upgrade process is weird...
At my DSOX2002A it is more simple, you don't need any manual at all. The upgrade process took about 5 minutes or so, I don't remember. (But the GDS-2000A might be a bang per buck when you need statistics, segemnted memory, search or mask testing. It's feature rich. My scope doesn't have it. (DSOX2002A can do mask testing if you buy an option for bloody money.  :( The same with segmented memory... Pay again!)
« Last Edit: June 13, 2013, 10:33:22 am by Hydrawerk »
Amazing machines. http://www.youtube.com/user/denha (It is not me...)
 


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