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Siglent SDS2000 new V2 Firmware

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nctnico:

--- Quote from: Performa01 on December 27, 2015, 01:17:00 am ---
--- Quote from: nctnico on December 20, 2015, 10:39:21 pm ---Still not going to return it?

--- End quote ---

Not me! ;)

In general it’s a great DSO already, with exceptional low noise and a rock solid trigger system.

Granted, there is a number of bugs yet, but none of them is a show-stopper and I’m positive they’ll be fixed eventually.

Average acquisition mode suffers from the memory limitation, but then again, for the price I paid for the SDS2304, I might have got a WaveAce 2024 at best, where apart from the lower bandwidth and it’s not being an MSO, I wouldn’t have had to worry about memory limitations in certain acquisition modes, as there are generally not more than 12kpts per channel available...

Eres is even worse, as it doesn’t even do what it promises, but then again, how many scopes in this class do have a useful resolution enhancement in the first place?

FFT isn’t terribly useful, but this is also not uncommon in this class and quite obviously only manufacturers who offer scopes with 12 or more bits (where FFT starts to make really sense) go to the effort to implement it in a way such as to get the most out of it.

--- End quote ---
Tektronix' TDS500/600/700 series are also 8 bit but they have a very usefull FFT feature (*) because there is no reason you need 12 bit for FFT to be useful! Same goes for Eres and averaging. Without long memory they are utterly useless because at some point you will want to zoom in on a long signal. You don't seem to perceive these as problems now but I'm quite sure you are going to see these limits as serious limitations of the SDS2000 in the near future when you are going to use it for real work. Having these limitations shows Siglent is still not on track with the firmware development of the SDS2000 and/or doesn't understand how an oscilloscope should work. The firmware update are just quick fixes to check items of the list and not to make the SDS2000 useful for any real work. The same goes for decoding: if that doesn't decode everything in memory then it is useless for any real work (been there, done that).

edit: (*) Tektronix' TDS500/600/700 have selectable FFT length and can average the FFT result making it ideal to look at the frequency response of a system or filter. More bits are only required if you need more dynamic range but for many measurements the 40dB range you can get from an 8 bit system is more than enough.

Performa01:
Another observation regarding pass/fail mode:

When looking at the screenshots in my previous post, we can see where the last violation of the mask occurred. The violating part of the trace appears highlighted in front of the mask, and for the first test (with slow rise time) it can be seen on the screen during the test, which is no surprise since the violation happens permanently on every single positive going edge (Pass_Fail_SlowRise_60s_Hint)




It is different for the second test though. As the violation only occurs once every 100000 signal periods, we really need to look close to spot the glitch every now and then – if we’re lucky. Usually we don’t see it. But on the screenshot it is clearly visible (Pass_Fail_Glitch_60s_Hint)




The funny thing is that in this screenshot, the glitch occurred pretty much at the same spot where it was in the screenshot when I initially showed my test signal (by triggering on the sync signal of the glitch pulse generator).
Now I wondered if every screenshot during the mask test would clearly show the violation or if it was just a lucky coincidence. So I ran the test again and took a number of screenshots at random times. And sure enough, none of them showed any mask violation, so I just had a lucky moment when I got the violation visible on that particular screenshot.

I tried persistence mode, but this doesn’t appear to have any effect during pass/fail test. It would be a nice improvement if we could indeed have some persistence during the test. For instance, not updating the screen display after a mask violation for the time according to the display persistence setting would be great, as this would clearly show why the mask test has failed – so I will add that to my wishlist. Maybe Siglent could implement that eventually?

Wuerstchenhund:

--- Quote from: Performa01 on December 27, 2015, 01:17:00 am ---Granted, there is a number of bugs yet, but none of them is a show-stopper and I’m positive they’ll be fixed eventually.
--- End quote ---

Or so you hope! :-DD  Don't forget that this scope is on the market for almost two years now, and still suffers from bugs that make it pretty useless for any real type of work.

As nctnico said, Siglent is just ticking off boxes of bugs that are reported by users. It also appears that software testing is pretty much non-existent in Siglent (otherwise they would have found the problems before releasing the firmware, most bugs are hard to miss even if you tried!), and relies on users to do find bugs and report them back instead.

In short, you pretty much bought a half-finished (ok, 70% finished) scope and agreed to work as a beta tester for free.  :-+

And people wonder how Siglent can be cheaper than other brands...


--- Quote ---Average acquisition mode suffers from the memory limitation, but then again, for the price I paid for the SDS2304, I might have got a WaveAce 2024 at best, where apart from the lower bandwidth and it’s not being an MSO, I wouldn’t have had to worry about memory limitations in certain acquisition modes, as there are generally not more than 12kpts per channel available...
--- End quote ---

Yes, the WaveAce is shit (guess who made them?) but there are many other alternatives which aren't.


--- Quote ---Eres is even worse, as it doesn’t even do what it promises, but then again, how many scopes in this class do have a useful resolution enhancement in the first place?
--- End quote ---

Most of them? The Keysight DSOX2k has a hires mode (10bit), as does the R&S HMO1000 (up to 16bit?). If I remember right even the Rigol DS2k/DS4k have some working hi-res modes.


--- Quote ---FFT isn’t terribly useful, but this is also not uncommon in this class and quite obviously only manufacturers who offer scopes with 12 or more bits (where FFT starts to make really sense) go to the effort to implement it in a way such as to get the most out of it.
--- End quote ---

That's nonsense, sorry. FFT does not need 12bit vertical resolution to "make sense", and is a pretty useful facility even on 8bit scopes, assuming of course the implementation isn't crap (like Rigol's limit of a few thousand points only) and works correctly (which it does on other scopes).

And scopes like the DSOX2k or the R&S HMO1000 show that even in this class FFT doesn't have to be shit.


--- Quote ---Only real annoyance is the trigger frequency counter, as it is low resolution, inaccurate and unreliable all at the same time.
--- End quote ---


Reliability is certainly an issue, but frankly what accuracy do you expect from a scope with a timebase that is spec'd with +25ppm? Without an external clock reference (i.e. GPSDO) the accuracy will be limited by nature.


--- Quote ---Where are the days, when we had analogue scopes with a Y-output, where we could hook up the frequency counter that had the resolution and accuracy that we needed for our task?
--- End quote ---

Y out was pretty much only available in a few specific Tek scope models and was also bandwidth limited, so it was only really useful for very specific cases.

Performa01:

--- Quote from: nctnico on December 27, 2015, 10:29:56 am ---Tektronix' TDS500/600/700 series are also 8 bit but they have very a usefull FFT feature because there is no reason you need 12 bit for FFT to be useful!

--- End quote ---

Well, yes, it depends on the requirements. When I reviewed the SDS2000 signal generator some posts earlier, I think I’ve demonstrated very clearly what a well implemented FFT can do even with just 8 bits, squeezing out an impressive dynamic range of more than 60dB by use of appropriate resolution enhancement techniques. But then again, this was still not enough to verify the spectral purity of the SDS2000 signal gen, and it is not enough for many other tasks as well.

But that wasn’t my point anyway. The point is that in my experience, only manufacturers that also make high resolution scopes have the inclination and experience to provide an FFT implementation that makes the most out of any existing hardware. Tektronix, as a well known manufacturer of RF gear, clearly have that experience. That’s probably why they knew that an 8 bit FFT wouldn’t cut it for many tasks, hence built a proper spectrum analyser into their MDO (mixed domain) series of scopes.



--- Quote from: nctnico on December 27, 2015, 10:29:56 am ---Same goes for Eres and averaging. Without long memory they are utterly useless because at some point you will want to zoom in on a long signal. You don't seem to perceive these as problems now but I'm quite sure you are going to see these limits as serious limitations of the SDS2000 in the near future when you are going to use it for real work.
--- End quote ---

Well, I think I have made very clear that having no long memory is a serious limitation and I really hope that Siglent is listening.

I don’t perceive it as a BIG problem now, because normal and peak detect work as expected, with up to 35/70 Mpts of memory, and my point was that there are still scopes in the market, at a similar price point or even more expensive, that don’t have more than just a couple of kpts of memory to begin with, no matter what acquisition mode. The WaveAce was just one example, Tektronix has similar offers.

And your assumption is wrong. I do use this scope for ‘real’ work (in my home lab), have used it even with the old V1 firmware, even though this wasn’t that great an experience.
Personally, I would even consider it for professional work, even though it’s not mature yet and operators need to be familiar with its quirks – and by now, not all quirks are even revealed. But then again, other scopes have quirks as well and we can never blindly rely on what a scope is telling us. For instance, the scopes of some particular A-brand gave us regular headaches with their intractable trigger system, which I consider much more a show stopper than any flaw on the Siglent.
 
Average acquisition mode is a nice feature to have, but certainly not essential for most tasks. Analogue scopes generally don’t have an average mode, yet engineers could make do with that for many decades.

Eres is a mixed bag anyway, because it inevitably limits the bandwidth depending on the actual sample rate. Sure, this might not be a problem in many cases if we had the full memory available, hence a constant high sample rate up to slow timebase settings, so I do hope Siglent will cure that eventually.
Still, if we really need high resolution, nothing can beat getting a proper 12 bit scope, which does not only give us the higher resolution, but also the accuracy, and the bandwidth doesn’t change with sample rate either.



--- Quote from: nctnico on December 27, 2015, 10:29:56 am ---Having these limitations shows Siglent is still not on track with the firmware development of the SDS2000 and/or doesn't understand how an oscilloscope should work. The firmware update are just quick fixes to check items of the list and not to make the SDS2000 useful for any real work.

--- End quote ---

Sorry, just because with the old V1 FW it didn’t meet your particular needs, claiming it isn’t useful for ANY real work is blunt bashing, since the basic functionality is sound. Only if I had paid two (or more like three with all the options) times as much to get a 300MHz/4Ch. mixed mode scope from some A-brand, I would complain loudly, but since I preferred staying cheap, I just have to be patient – as long as Siglent cares to improve their products based on user experience.



--- Quote from: nctnico on December 27, 2015, 10:29:56 am ---The same goes for decoding: if that doesn't decode everything in memory then it is useless for any real work (been there, done that).

--- End quote ---

Who says that it doesn’t?

All I can tell so far is that it works just like any other MSO or LA. It captures screen by screen at the chosen timebase, and if this results in thousands of packets per screen, one will of course not see any meaningful decoding without stopping acquisition and zooming into the acquired data.

This even works in history mode, which essentially is segmented memory anyway. There are 14 Meg available when using digital channels and as always with segmented memory, we can chose to have 14 Mpts and only one segment if we’re interested in lots of data for just one single trigger event, or e.g. 416 segments with 70kpts each if we’re interested in analysing lots of subsequent acquisitions (with still plenty of data for each trigger event).

nctnico:
The V2 firmware doesn't look like it is much better than the V1 firmware. Just more things plastered over. If you want to use an oscilloscope's FFT function to check the spectral waveform purity of the signal generator than you are clearly using the wrong tool. Either way the value for money the SDS2000 offers just isn't good because a lot is severely limited at best. You can buy a used DSO for the same amount of money which has proper FFT and works as advertised. The added value of the SDS2000 is in the MSO, protocol decoding and advanced features but it is those that cause most of the headaches. If I didn't need protocol decoding I'd never bought the SDS2000 to begin with! Also your remarks about averaging and high res being OK with a short memory is nonsense. They are very handy to clean a signal up so you can make accurate cursor measurements. I made good use of that in one of my recent projects on a trace which was several seconds long.

Still I'd like to see how the protocol decoding works in the V2 firmware and whether you can zoom (using the s/div knob) into the bits of a message without losing the decoding. And does zoom mode work together with decoding in the V2 firmware?

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