GDS-2000A series New economic oscilloscope by GW Instek comes to market

[marmad]

Well, really? Then it means that measurements by Kiriakos are wrong. http://www.ittsb.eu/GDS-2102A%20Wfms%20measurments.html

Of course, it was obvious when he posted them that his equipment wasn't reading the low-level signal correctly - and that his figures for < 50ns were wrong. I tried to explain that to him but he didn't seem to understand; he seems to think he discovered something that the GW-Instek engineers overlooked   

[Hydrawerk]

It has arrived... and yes, that green tape is our friends at Homeland Security and Border Protection having opened my box when it hit the shores in Long Beach.  Go-go government bureaucracy!



(more coming later once I get home and play with it over the weekend)

Hey, my brand new DSOX-2002A was not packed in a plastic bag. Oh, why? 

[Hydrawerk]

And it seems to me that Rigol DS2000 and Agilent DSOX2000 have better shielding. Their power supplies are completely hidden in a metal box. Not at GDS-2000A.

[bonanz]

greg thanks for the video good work.

i dunno why you were so worried and apologetic about quality etc. I thought it was all fine. looking forward to follow ups.

[grego]

It's called "terror of the unknown".

I'm trying to find some time to do some follow-up work - marmad had a couple of questions he PM'd me and I know there's interest in the LA module so that'll likely be my next effort.  I just have to get one of my dev kits set up to provide some RS-232 and I2C and such so I can demonstrate it.

If I ever get off my butt I may do a teardown as well.

Ah, if only I didn't have a job and a family and had unlimited funds this would be so much easier!

Thanks for the thumbs up.

[Hydrawerk]

According to the manual the GDS-2000A has no fine vertical or horizontal setting. Just like Owon SDS series... But Rigol, Agilent and others have fine vertical and horizontal settings.
This might be not a big disadvantage.

[grego]

According to the manual the GDS-2000A has no fine vertical or horizontal setting. Just like Owon SDS series... But Rigol, Agilent and others have fine vertical and horizontal settings.
This might be not a big disadvantage.

I called this out a couple times already.  And in the video.  And I talked to Instek about it -- they have added it to their firmware roadmap.

[marmad]

@Greg:

Perhaps you can do a quick test (no need to add it to your video) if you're able to generate a 10MHz sine wave (1MHz or 5MHz would likely work fine as well)? Following in the lines of this post from another thread, you would just send the test signal to one channel, and then slow down the time base until you're at a sample rate of 100 or 200MSa/s. Then either stop the DSO and zoom into the ~50ns/div range - or enter zoom mode (as in the images) and zoom to the smaller range. Then do a screen grab and post it here. I'm guessing that the Instek will reproduce the waveforms symmetrically just as the Rigol and LeCroy do - but that the Agilent X-Series appears unable to do.

[grego]

I can give that a whirl.  Only up to a 1MHz right now but I will post the results.

[marmad]

I can give that a whirl.  Only up to a 1MHz right now but I will post the results.

Great! Also, if you noticed us measuring the Trigger Out delay over in the Rigol thread, I'd be curious to know what it is on the Instek.

BTW, in a possibly (un)related note, I noticed in the 2000A manual that the No-Go Output was optically-isolated, requiring a pull-up for proper output voltage. I wonder if the Demo 1 output used for the Trigger Out could be similarly configured, explaining the low voltage level.

[Hydrawerk]

Demo signal optically isolated? Why? It's unlikely.

[grego]

Demo signal optically isolated? Why? It's unlikely.

He was talking about the fact that Trigger Out is on the Demo 1 pin, not that it's a demo output.

[marmad]

Hey Greg,

You've had the DSO about 3 weeks now - I'm curious where things stand for you: likes, dislikes, general feelings about the UI, etc.  I don't really need more video if time is tight for you - just some scribblings and a screen cap or two would suffice 

[grego]

I haven't had as much time as I would like to fart around with it of late but overall my thoughts:

1. The scope "feels" good.  I like they layout of the controls.  One thing I kind of wish they did was provide a rubberized ring on the outside to improve the feel of the rotary knobs a little bit.

2. I wish the traces were a little bit finer - it doesn't look like there's pixel-doubling going on but for lack of a better term the "thickness" of the traces.  Not major.

3. Scope is very responsive to control changes which is great.  No delays.

4. Feature-rich for the price - I mean really, I got it for ~$1700 USD for a 200Mhz 4 channel scope with good manufacture, quality components and a company that has a solid reputation here in the US.

5. As I mentioned before the responses from Instek have been top-notch.  I just got a reply back from engineering on my latest complaint of not being able to remove the Go-NoGo min/max lines.  They outlined the 'procedure' to remove it and added they are sending it back into engineering to make it easier (because, to be honest, what they outlined was stupid).

6. I wish I could speak more about the LA but I just have NOT had time to sit down with it yet so I can't speak to it.  However, I know you can decode off the digital lines at least.

Overall, I'm really happy with the expenditure, with the caveat that I need to spend time with the LA to justify that $800 purchase.  I mean for what I need it's a scope that I will be able to use for years.  I completely understand that I 'overbought' on equipment - I didn't NEED 200Mhz, I didn't NEED the MSO function but it's all helpful and to be hones the price delta wasn't large enough for me to really worry about it.  So for a first bench scope to replace my Pico 3206-A I'm completely satisfied.

There will be more coming once I have some breathing space to sit down and cover some more features.  Between work, my kids soccer schedule and school for me I've been pretty busy.  And heck, Iron Man 3 opens this weekend too. ;-)

[marmad]

I haven't had as much time as I would like to fart around with it of late but overall my thoughts:

1. The scope "feels" good.  I like they layout of the controls.  One thing I kind of wish they did was provide a rubberized ring on the outside to improve the feel of the rotary knobs a little bit.

2. I wish the traces were a little bit finer - it doesn't look like there's pixel-doubling going on but for lack of a better term the "thickness" of the traces.  Not major.

3. Scope is very responsive to control changes which is great.  No delays.

4. Feature-rich for the price - I mean really, I got it for ~$1700 USD for a 200Mhz 4 channel scope with good manufacture, quality components and a company that has a solid reputation here in the US.

5. As I mentioned before the responses from Instek have been top-notch.  I just got a reply back from engineering on my latest complaint of not being able to remove the Go-NoGo min/max lines.  They outlined the 'procedure' to remove it and added they are sending it back into engineering to make it easier (because, to be honest, what they outlined was stupid).

6. I wish I could speak more about the LA but I just have NOT had time to sit down with it yet so I can't speak to it.  However, I know you can decode off the digital lines at least.

Overall, I'm really happy with the expenditure, with the caveat that I need to spend time with the LA to justify that $800 purchase.  I mean for what I need it's a scope that I will be able to use for years.  I completely understand that I 'overbought' on equipment - I didn't NEED 200Mhz, I didn't NEED the MSO function but it's all helpful and to be hones the price delta wasn't large enough for me to really worry about it.  So for a first bench scope to replace my Pico 3206-A I'm completely satisfied.

Thanks! That fills in some of the missing blanks - and the review of the LA I can easily wait for.    My only other ongoing desire-to-know is: with all of the posting about interpolation / type of interpolation / affect on sampling, etc. that a number of us have been doing these last weeks, I'd like to know what a waveform looks like on the Instek when undersampled. The Rigol switches to linear interpolation - which, although a little boxy, is symmetrical - and the Agilent just makes a total mess of it (I don't even know what it's doing - but it's screwing up the samples somehow). Is the Instek still using sin(x)/x at slower sampling speeds? If so, how does it look? The test I mentioned before (with a reasonably fast sine wave) would satisfy my curiosity - whatdayasay? Huh? Puh-leeeeze? (I'm banking on your reveal of fatherhood) 

There will be more coming once I have some breathing space to sit down and cover some more features.  Between work, my kids soccer schedule and school for me I've been pretty busy.  And heck, Iron Man 3 opens this weekend too. ;-)

He's kind of like a walking, talking MSO 

[Hydrawerk]

Try how is the waveform update rate affected by turning on more channels, eight auto measurements, FFT or cursors. On my DSOX2002A it is not affected at all by anything. On the other hand, you have only 4 auto measurements + DVM, it's not much for a four channel scope.  Well, my scope is 2 channel, but it could be 4 channel.

[marmad]

Try how is the waveform update rate affected by turning on more channels, eight auto measurements, FFT or cursors. On my DSOX2002A it is not affected at all by anything. On the other hand, you have only 4 auto measurements + DVM, it's not much for a four channel scope.  Well, my scope is 2 channel, but it could be 4 channel.

You seem to think waveform update rate is the most important thing, but it's not - it's not even in the top three most important. As long as I have a reasonably fast update rate with a certain sample length at a couple of time base settings, that's enough - because if I want to specifically look for jitter, anomalies, etc. I will use those settings.  But it appears that the Agilent X-Series is trading waveform fidelity at slower sampling speeds (which, IMO, is much more important) for more uniform waveform update rates  - and that is much worse than just having slower rates caused by using more functions.

[Hydrawerk]

Oh, not really, if you work mainly with digital signals, you may rather need long 56Mpoints memory and you don't care about waveform update rate because you use Single shot most often.

[grego]

Thanks! That fills in some of the missing blanks - and the review of the LA I can easily wait for.    My only other ongoing desire-to-know is: with all of the posting about interpolation / type of interpolation / affect on sampling, etc. that a number of us have been doing these last weeks, I'd like to know what a waveform looks like on the Instek when undersampled. The Rigol switches to linear interpolation - which, although a little boxy, is symmetrical - and the Agilent just makes a total mess of it (I don't even know what it's doing - but it's screwing up the samples somehow). Is the Instek still using sin(x)/x at slower sampling speeds? If so, how does it look? The test I mentioned before (with a reasonably fast sine wave) would satisfy my curiosity - whatdayasay? Huh? Puh-leeeeze? (I'm banking on your reveal of fatherhood) 

Here you go - 1Mhz sine, dropped down to 10ms which gave me a 10MSPS rate, single-shot, zoomed in to 200ns.  Looks like it's keeping sin(x)/x to me.

[marmad]

Here you go - 1Mhz sine, dropped down to 10ms which gave me a 10MSPS rate, single-shot, zoomed in to 200ns.  Looks like it's keeping sin(x)/x to me.

Great, thanks very much for that! Yes, it's definitely sin(x)/x - and it looks good too.    I'm only wondering how you know your sample rate; I don't see it on the Instek's display.

[grego]

Here you go - 1Mhz sine, dropped down to 10ms which gave me a 10MSPS rate, single-shot, zoomed in to 200ns.  Looks like it's keeping sin(x)/x to me.

Great, thanks very much for that! Yes, it's definitely sin(x)/x - and it looks good too.    I'm only wondering how you know your sample rate; I don't see it on the Instek's display.

It's under the Acquire menu (which I didn't leave up in this since it was single shot).  Basically, bring up the Acquire menu and one of the buttons shows the sample rate.  I upped the timebase until it read 10MSPS and then single shot it.

[marmad]

It's under the Acquire menu (which I didn't leave up in this since it was single shot).  Basically, bring up the Acquire menu and one of the buttons shows the sample rate.  I upped the timebase until it read 10MSPS and then single shot it.

Nice... any chance you can do the exact same thing one more time in 'dots' mode (no interpolation)? I know, I know, I'm keeping you from your kid's soccer - or Iron Man 3 - but it won't take too much more time 

[marmad]

Oh, not really, if you work mainly with digital signals, you may rather need long 56Mpoints memory and you don't care about waveform update rate because you use Single shot most often.

Huh? Why would you necessarily need single shot mode more for digital signals? And I don't think there's a serious EE in this forum who thinks the waveform update rate is the most important specification of a DSO.

[Hypernova]

I 'overbought' on equipment

Heh, what does that make me, a guy that spent 4 months salary on my MSOX3014? I'm quite possibly the only private person in the whole of Taiwan to do such a thing. Good thing my parents live in New Zealand so all they could do when I told them was yell at me over Skype.

A few thing that you can check if you got the time:
Can you try the responsiveness of the scope when you have every feature turned on? The Tek scope I used before at work grind to a halt if you turn on max memory, FFT, measurements and digital all at once. We are talking screen update time in the order of seconds. It's one of the reason I bought Agilent, I just don't want to stroke a turtle for work any longer.

Does the digital channels also work in Roll display mode, Tek scopes don't which is retarded. And if they do how far does the bus decode display lag behind the channel signals, on my Agilent the decoded signals be it I2C or parallel bus the display falls behind like they are runners on a track but will "catch up" smoothly if I press stop.

FFT resolution, the Lecroy's at work here only get down to 200Hz even if you dial the sample time up, with Agilent I can get down to to sub Hz. if I sample long enough.

[Hydrawerk]

  You can never go wrong with Agilent.