Siglent Technologies America received the following unsolicited email... - Page 1
Forum section: electronics / testgear

author: nixxon
author_rank: Frequent Contributor
timestamp: March 08, 2016, 10:31:09 am
content: I just received an email from Siglent marketing:QuoteBoth the Tek 2246 and the Tek 2465B are legacy analog scopes from the 80's.http://w140.com/tekwiki/wiki/2246http://w140.com/tekwiki/wiki/2465B

author: nctnico
author_rank: Super Contributor
timestamp: March 08, 2016, 10:57:31 am
content: Siglent must be very proud to have ONE happy customer! Totally oblivious to the fact that the people working there seem to have very little understanding on how to use an oscilloscope properly. BTW Siglent America also posted the same e-mail here but it got deleted and I suspect this thread will be deleted as well.

author: markone
author_rank: Frequent Contributor
timestamp: March 08, 2016, 12:59:22 pm
content: Quote from: nixxon on March 08, 2016, 10:31:09 amIf it's not a fake, those people lived under a rock for a while

author: Karel
author_rank: Super Contributor
timestamp: March 08, 2016, 01:37:52 pm
content: Don't buy anything from Siglent if you are not sure you don't want to sell it on Ebay later...https://www.eevblog.com/forum/testgear/siglent-they-filed-a-'wrongful-trademark-claim'/

author: ataradov
author_rank: Super Contributor
timestamp: March 08, 2016, 05:13:20 pm
content: They should send complaints as well. That's going to be an unprecedented level of spam.Seriously, one email they decided to share?

author: TheSteve
author_rank: Unknown
timestamp: March 08, 2016, 05:38:40 pm
content: They were bound to come across a single happy customer eventually.

author: tautech
author_rank: Super Contributor
timestamp: March 09, 2016, 09:00:31 am
content: Guys, why on earth wouldn't you want to know which Agilent a $499 Siglent cleaned up in the letter the OP posted?You can see the SDS1000X capabilities in rf-loops threadhttps://www.eevblog.com/forum/testgear/siglent-sds1000x-series-oscilloscopes/

author: nctnico
author_rank: Super Contributor
timestamp: March 09, 2016, 09:25:09 am
content: Quote from: tautech on March 09, 2016, 09:00:31 amBecause the letter calls an obsolete analog oscilloscope from the (early?) 80's 'the industry standard'. Besides that there is so little information about the circumstances of the measurements that it is better to attribute the measurement results to dumb luck than anything else. For example: did they used 1:10 probes with the other oscilloscopes? And did they use features like bandwidth limiting, filtering, high-res, etc to clean the signal up?

author: markone
author_rank: Frequent Contributor
timestamp: March 09, 2016, 01:05:32 pm
content: Quote from: tautech on March 09, 2016, 09:00:31 amI'm an happy SDG2042X owner so far (even if i'm still awaiting for some well known bugs fix and i fear "factory installed rust") and i'm not saying that Siglent rigs are usually bad nor that SDS1000X is a bad scope, but the statement :All our analog scopes, except the very cheap ones, could see it clearly but none of our digital scopes could see it. We had many types of digital scopes from older nice, newer decent,to very expensive high end mega G/S scopesshould be elaborated specifying which "very expensive high end mega G/S scopes" were involved in the task, otherwise the whole thing seems pretty a fake build up.If they are referring to first generation windows based DSOs, well i'm not surprised, some of them were shamefully noisy, even my GDS-2072E blows them out of the window under this aspect, but we have to keep in account at least ten years of technical evolution.Talking about the SDS1000X i still have some doubts about its build quality : too many soldering oops and "hammered" metal shielding case spotted on Dave's teardown for my personal taste.Pre-production unit ?

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: March 09, 2016, 01:35:51 pm
content: Quote from: markone on March 09, 2016, 01:05:32 pmIt most likely*is*completely faked. I mean, seriously, even if we assume for a moment that the noise floor of the SDS1000X was excellent (which I doubt it is), how likely is it that a real engineer with real experience would write an "unsolicited" letter to the manufacturer?The other question is which serious business would invest in Chinese B-brand scopes, some small one man shops aside (and those rarely have exposure to many different scope types).QuoteIn what way is the operating system on the scope related to the noise floor?And I'm sorry to have to say this but your GDS-2072E doesn't blow anything "out of the water", and certainly not those old scopes. The first Windows scopes from HP (Infiniium 54800A, coming out around 1998 so almost two decades ago) certainly had lots of issues but the noise floor wasn't one of them. Plus these were pretty much all scopes with bandwidths much higher than the 70Mhz of your GW Instek, and more bandwidth means more noise.Take something slightly newer than the old Infiniiums, i.e. LeCroy's first gen Windows scopes (WavePro 7k, WaveMaster 8k) and you'll that the noise floor is actually pretty good for scopes with bandwidths between 1Ghz and 6GHz, even by today's standards. Hell, even Tek managed to get some decent noise floor out of their otherwise very poor TDS5000 scopes.A low noise floor isn't something that was just recently discovered.But I agree that the statement"very expensive high end mega G/S scopes"smells like BS. Pretty much the kind of BS I'd expect a sleazy B-brand like Siglent to pull off.The alternative to this is that whoever wrote that letter is utterly clueless about what a somewhat newer scope can do.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 09, 2016, 02:08:17 pm
content: Yes, let's receive praise from the one engineer who doesn't know how to push the bandwidth button, or "Hi-Res" acquisition mode... ??!Tim

author: markone
author_rank: Frequent Contributor
timestamp: March 09, 2016, 02:11:46 pm
content: Quote from: Wuerstchenhund on March 09, 2016, 01:35:51 pmAre you sure ?Have you ever touched a GDS-2000E scope (or even get close) ?Quote from: Wuerstchenhund on March 09, 2016, 01:35:51 pmIt seems that you changed a lot yout mind in last two years :Quote from: Wuerstchenhund on June 02, 2013, 05:55:34 pm

author: AF6LJ
author_rank: Unknown
timestamp: March 09, 2016, 02:25:26 pm
content: I always find it hard to accept as valid testimonials that do not have a real name and company attached.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: March 09, 2016, 02:36:36 pm
content: Quote from: markone on March 09, 2016, 02:11:46 pmYes, pretty sure.QuoteNo, I haven't, the GDS-2000 is not exactly in my price or bandwidth class. But I've read the specs and watched the videos. And while it certainly looks like a decent scope, nothing I saw re. noise was in any way outstanding (neither positive or negative). But I've come across a lot of those older Windows scopes you mentioned.But since you have a GDS-2000, how about you demonstrate how it "blows" other scopes "out of the water"? Let's see some of that incredibly low noise floor!Quote from: Wuerstchenhund on March 09, 2016, 01:35:51 pmQuoteWell, the calender here on planet Earth says it's March 2016 so that's much closer to three years than two. But no, I haven't changed my mind. Three years ago the SDS1102CNL was a nice entry level scope. What it did it did pretty well for something that was $350 or so back then and which was bought for a somewhat risky task that might easily have led to its destruction it (which is why I bought a bottom-of-the-barrel scope in the first place).That doesn't mean I endorse Siglent or the way they do business.And your point is?

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: March 09, 2016, 02:39:22 pm
content: Quote from: AF6LJ on March 09, 2016, 02:25:26 pmYou'll find it hard to find many testimonials for test gear that have a real name and company attached. There are various reasons why companies in general avoid giving testimonials using their name, unless it's something they benefit from it in any form (i.e. through a marketing agreement).

author: markone
author_rank: Frequent Contributor
timestamp: March 09, 2016, 02:42:58 pm
content: Quote from: Wuerstchenhund on March 09, 2016, 02:36:36 pmMy point is that you deeply change your approach depending on situations, that's it.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: March 09, 2016, 02:55:25 pm
content: Quote from: markone on March 09, 2016, 02:42:58 pmSo because 3 yrs ago I saida particular Siglent scopewas nice and three years on I have a negative opinion aboutSiglent as a companyyou believe I "deeply change my approach depending on situations"? Are you serious?BTW (since it looks like you need to have that explained to you, which is already silly in its own regard): changing one's mind and being able to re-evaluate when a situation changes and new facts are come to light is generally considered a positive thing, and one of the things that is expected of a good engineer. Having an opinion and being stuck in it despite facts showing the contrary simply isn't.So, are we gonna see the demonstration how the GDS-2000E blows "everything out of the water" or what?

author: markone
author_rank: Frequent Contributor
timestamp: March 09, 2016, 03:13:21 pm
content: Quote from: Wuerstchenhund on March 09, 2016, 02:55:25 pmDunno where you saw "blowseverythingout of the water", i was referring tosomeold noisy windows based DSOs.Anyway, just in case it was not yet clear, i do not care at all about what you think or say, you are so pretty with, your world it's too good to be true ....

author: nctnico
author_rank: Super Contributor
timestamp: March 09, 2016, 03:32:14 pm
content: Quote from: Wuerstchenhund on March 09, 2016, 02:55:25 pmThe GW Instek GDS2000E series certainly has several very strong points as I wrote in my review:https://www.eevblog.com/forum/testgear/gw-instek-gds2204e-%28200mhz-4-channel-dso%29-review/. Based on the tests RF-loop has posted in the thread Tautech pointed to the noise in the GDS2000E seems to be lower than the Siglent scope he used. Besides that the GDS2000E has input filtering with which you can clean small signals up nicely. For example this approx. 500uVpp 1.6kHz sine wave with the input filter set to 10kHz:

author: AF6LJ
author_rank: Unknown
timestamp: March 09, 2016, 03:46:45 pm
content: Quote from: Wuerstchenhund on March 09, 2016, 02:39:22 pmYou are certainly right; this is why I don't believe a damned one of them.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: March 09, 2016, 04:11:50 pm
content: Quote from: nctnico on March 09, 2016, 03:32:14 pmThanks for the screenshots. That certainly doesn't look bad, although I'd expect it to as the bandwidth is limited to 10kHz.Could you do some screenshots showing the noise floor (no signal) with a 20MHz bandwidth limit and at the full 200MHz bandwidth?Just to make this clear: I have no problems believing the GDS-2000E has a better noise floor than some or all of Siglent's scopes. But I have a hard time believing the "blowing out of the water" in comparison to older high end scopes with a vastly larger bandwidth. Because for that to be the case the full BW (in this case 70MHz) noise floor must have been several magnitudes better than the noise floor of these older scopes.

author: nctnico
author_rank: Super Contributor
timestamp: March 09, 2016, 04:49:12 pm
content: Quote from: Wuerstchenhund on March 09, 2016, 04:11:50 pmNo problem!Note there is a small DC offset but that is because I did not let the scope warm up for half an hour. The acquisition mode is peak-detect.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: March 09, 2016, 07:26:36 pm
content: Quote from: nctnico on March 09, 2016, 04:49:12 pmThanks! That looks pretty good indeed.Just as a comparison ( and to give some perspective to show the silly claim that has been made about "blowing" certain scopes "out of the water" as what it is, hot air), here are some screenshots from a 9yr old LeCroy WavePro 7300A, a 3Ghz scope with a front end that was designed at the end of the '90s, and is the same frontend as the one in LeCroy's first generation Windows scope (WP7000). The only difference is the OS (W2k vs WinXP).That doesn't look like several magnitudes of difference to me. And the old HP Infiniiums weren't that much worse, in fact the low bandwidth variants (<1GHz) were a lot better than this old WavePro (which is understandable, more bandwidth = a lot more noise).So much to the claim of "blowing out of the water"I guess that's settled then.Quote from: markone on March 09, 2016, 03:13:21 pmPretty strong words from someone who spouts a lot of hot air but when push comes to shove needs someone else step in to show what the GDS2000 can doNext time just don't make any stupid unsubstantiated claims, and you'll look a lot less silly. Guranteed.

author: nctnico
author_rank: Super Contributor
timestamp: March 09, 2016, 08:10:52 pm
content: My Agilent DSO7104A is a lot noisier though. Even with the bandwidth limit on and the input set to 50 Ohm the noise is 1mVpp / 510uV RMS!

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: March 09, 2016, 09:15:48 pm
content: Quote from: nctnico on March 09, 2016, 08:10:52 pmI remember that the old DSO6k/7k were pretty noisy scopes. The same is true for some (strangely not all) DSOX4000.But I think very low noise isn't much an issue for this class of scope as much as it is for low-end/entry-level scopes, as on more advanced scopes you'd probably use an active probe for very low voltage measurements anyways, while low end scopes usually lack the interfaces for such probes (plus the probe would cost more than the scope).

author: vk6zgo
author_rank: Super Contributor
timestamp: March 10, 2016, 05:42:12 am
content: Quote from: nixxon on March 08, 2016, 10:31:09 amSorry this is bit messy,but quoting inside a quote gets like that!

author: rf-loop
author_rank: Super Contributor
timestamp: March 10, 2016, 09:41:53 am
content: Quote from: nctnico on March 09, 2016, 04:49:12 pmHere some quick tests with Siglent SDS1202X.Using Full BW, 20MHz BW and using ERES 3.0 (enchanged resolution)As we can see there with GW examples there was also used10kHzfiltering. Three bottom images show more clearly what is ERES. Someone can do same with 10kHz filtering?Full BW here mean that scope is 200MHz model SDS1202X. Measured true BW 280MHz -3dB ref 0dB at 1MHz.Also it is good to note how intensity grading works and in some cases give more. (GW instek full BW noise floor compared to Siglent full BW noise floor is good example)Full BW noise floor without signal.20MHz bandwidth noise floor without signal.~500uVpp sine, 1.6kHz. Full BW.~500uVpp sine, 1.6kHz. 20MHz BW.~500uVpp sine, 1.6kHz. 20MHz BW + ERES 3.0Quote from: nctnico on March 09, 2016, 03:32:14 pm~5mVpp sqr. Full BW~5mVpp sqr. 20MHz BW~5mVpp sqr. 20MHz BW + ERES 3.0Think what happend if add here now 10kHz filter as in GW instek was used in bottom image!(note time scale)Quote from: nctnico on March 09, 2016, 03:32:14 pm

author: nctnico
author_rank: Super Contributor
timestamp: March 10, 2016, 10:22:41 am
content: At 1Gs/s the noisefloor will appear less because peak-detect will accumulate less noise.

author: markone
author_rank: Frequent Contributor
timestamp: March 10, 2016, 10:24:34 am
content: Quote from: rf-loop on March 10, 2016, 09:41:53 amQuote from: nctnico on March 09, 2016, 04:49:12 pmRF-loop, could you please repeat captures with :- peak-detect acquisition mode, as for GW Instek- Vpp & Vrms meas turned ON, as for GW Instek- eres turned OFF, as for GW Instek

author: rf-loop
author_rank: Super Contributor
timestamp: March 10, 2016, 11:19:23 am
content: Quote from: markone on March 10, 2016, 10:24:34 amAnd then also GW turned 10kHz filer off.(in these SDS images you can see also without ERES as can read image texts )

author: rf-loop
author_rank: Super Contributor
timestamp: March 10, 2016, 11:25:23 am
content: Quote from: nctnico on March 10, 2016, 10:22:41 amYes but SDS can forgive this head start for GW.

author: markone
author_rank: Frequent Contributor
timestamp: March 10, 2016, 11:46:23 am
content: Quote from: rf-loop on March 10, 2016, 11:19:23 amNo problem about that, eres is a nice feature missing in GW, so just to compare apples with apples.

author: rf-loop
author_rank: Super Contributor
timestamp: March 10, 2016, 12:13:55 pm
content: Quote from: markone on March 10, 2016, 11:46:23 amIt can also think ERES works result looks something like BW filter... with this setting in image ERES 3.0 affect roughly something like 10kHz filter. (I have not measured its response using different samplerates and different ERES levels between 0.5 to 3.0)So this is as much apples to apples still... in case that GW do not have ERES and Siglent do not have (in this model) DSP BW filter as GW have. (Old SDS1000 have)But as can see in last image (where step response is better visible) it can also easy see with just eyes that if do this using 10kHz filter result is very different but still not so much noise)And just tested noise floors and noise with signals 500uVpp. Using 10MSa/s - 100MSa/s and gfull 1GSa/s. Using normal or peak detect. (and of course full BW)1GSa/s = not any difference if normal or peak (of course)100MSa/s = not visible difference if peak or normal (perhaps because still enough samples overlayed on the screen)10MSa/s = peak detect rise peaks visually to same level as 1GSa/s

author: markone
author_rank: Frequent Contributor
timestamp: March 10, 2016, 12:26:59 pm
content: Quote from: rf-loop on March 10, 2016, 12:13:55 pmI was saying the same thing but i was'nt enough clear, i vote to repeat all test both sides (if nctnico agree) without any kind of signal processing just to have a glimpse about what comes out from analog front end / ADC section.We can decide together which settings to use : input termination, time base, number of sample, acquisition mode.Of course i can take captures also with my scope but it's the 70Mhz BW model.

author: Performa01
author_rank: Super Contributor
timestamp: March 10, 2016, 12:51:25 pm
content: Quote from: nctnico on March 09, 2016, 04:49:12 pmI wonder how anyone can show full 200MHz bandwidth using a slow sample rate of 100MSa/s?

author: nctnico
author_rank: Super Contributor
timestamp: March 10, 2016, 01:08:32 pm
content: @Performa01: With peak detect you get full bandwidth at lower storage (!) samplerates. The ADC is still running at full speed but the min/max values for several samples within the storage sampling interval get stored in memory.@RF-loop: enable measurements for RMS and peak-peak and you'll see that even though the trace looks thinner the numbers will be the same. Also note that Eres only works on record lengths up to 14kpts on Siglent scopes so it is rather useless for any real world use. For example: a while ago I had to do some accurate measurements on a (single shot) signal lasting several seconds with components over 1kHz. 14kpts is not enough for such measurements!

author: rf-loop
author_rank: Super Contributor
timestamp: March 10, 2016, 02:09:48 pm
content: Quote from: markone on March 10, 2016, 10:24:34 amHere some examples. (add for earlier post with other images)1 noise floor as earlier but here 10MSa/s and Peak mode2 500uVpp 1.6kHz sine with full BW and Peak mode.3 500uVpp 1.6kHz sine with 20MHz BW and Peak mode.Selected 10MSa/s because this give more "dramatic" display where hi and lo peak traces can see better separated.

author: nctnico
author_rank: Super Contributor
timestamp: March 10, 2016, 02:32:44 pm
content: Without numbers (measurements) the pictures are meaningless because the differences are too small to see.

author: rf-loop
author_rank: Super Contributor
timestamp: March 10, 2016, 04:01:25 pm
content: It strongly looks like GWS2000E do not have true 1mV/div full resolution sensitivity.1mV/div looks like just as digital zoom.. Perhaps 2mV/div is lowest true.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: March 10, 2016, 05:36:03 pm
content: Quote from: nctnico on March 10, 2016, 02:32:44 pmIndeed. The Siglent screenshots are nothing more than pretty pictures. Rf-loop, you should turn on Vpp and Vrms + statistics.I also have to say I do agree with markone on that these measurements are pretty useless with ERES (which narrows the bandwidth but extends the resolution) or super narrow digital filters on, or overly low sample rates which are inadequate to correctly resolve any noise.I'd recommend to use similar settings as I did, most sensitive vertical setting (2mV/div in my case), 500ns/div timebase, max. memory/highest sample rate achievable in that mode, inputs to 1Mohms, real-time sampling mode (no ETS/ERES, no Peak Detector). Measurements and statistics (if available) for Vpp and Vrmsenabled. Do this for 200MHz bandwidth (or full bandwidth for 200MHz scopes) and 20MHz (which is a standard BW limiting mode).Then we have comparable results.

author: rf-loop
author_rank: Super Contributor
timestamp: March 10, 2016, 06:38:52 pm
content: Quote from: Wuerstchenhund on March 10, 2016, 05:36:03 pmYou can not read/analyze oscilloscope screen?Yes I know it is difficult, very difficult. (and of course RMS and stat impossible)I have used over 40 years analog oscilloscopes and all what mostly have (specially some more time ago) there was only trace and settings. Well with these "just nice images" I and we analyze many things without any problems and mostly solve what ever problem we have been analyzing.But what ever. Here's one image to this entertainment.Note: After more deep inspection. RMS value in image is around right but it is NOT noise RMS. It is noise + DC power.If calculate this noise without DC offset it is much more low. So, it is important to look image and not only "trust" numbers and/or misapply these.

author: nctnico
author_rank: Super Contributor
timestamp: March 10, 2016, 06:56:51 pm
content: Here is the noise level of the GW Instek which shows the numbers are in the same ball-park with the same settings (full bandwidth, 500ns/div).The whole point of having a digital scope is more than just showing signals and doing signal analysis.

author: rf-loop
author_rank: Super Contributor
timestamp: March 10, 2016, 07:25:12 pm
content: Quote from: nctnico on March 10, 2016, 06:56:51 pmYes, we can say, around same ball park.Btw, how many horizontal data points it have on the screen. 500 samples/div? Or, do it make some kind of decimation for display. If there is decimation for display what data it use for measurements. Siglent do not decimate for display so all sample points are also included for meas. (exept of course if there primary decimation after ADC for lower samplerate than full ADC speed)

author: nctnico
author_rank: Super Contributor
timestamp: March 10, 2016, 07:29:57 pm
content: Quote from: rf-loop on March 10, 2016, 07:25:12 pmAt 500ns/div and 1Gs/s there are 500 samples/division so 5000 in total which about matches the number of samples the Siglent is using.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: March 10, 2016, 08:07:24 pm
content: Quote from: rf-loop on March 10, 2016, 06:38:52 pmI can, and I'm well aware that looking at the waveform alone is as useful as reading from fish guts when it comes to determine the actual noise parameters.QuoteThat is all well and good, and I don't want to start a debate over the old days but back then a lot of what read from waveforms was pretty much a guestimate. Also, engineers had often go to great length to work around the many shortcomings of an analog scope. Plus there were a lot of things they missed because it went under in blooming and other effects.I mean, humans survived for millenia without penicilin, but that doesn't mean we should go back to the days of blood letting or putting Mercury in wounds.So instead of guestimating and counting pixels or other nonsense let's just for once make use of the wonders of modern technology and use the scope's measurement function.QuoteThanksThat's not bad.

author: markone
author_rank: Frequent Contributor
timestamp: March 10, 2016, 11:20:49 pm
content: Quote from: Wuerstchenhund on March 10, 2016, 05:36:03 pmHere are a couple of screens from mine 2072E, 500nS 10Mpts open 1Mohm input, no digital sample filtering.I purposely set vertical scale to 2mV for easier compare with LecroySpecs are for 70Mhz full BW, -3dB point is actually quite higher.@rf-loop : thank you for the tests, pls turn off ERES, digital filtering and enable measuresPS : 200Mhz unlock hack for this scopes line would be highly appreciated.

author: rf-loop
author_rank: Super Contributor
timestamp: March 11, 2016, 07:25:00 am
content: Quote from: markone on March 10, 2016, 11:20:49 pmWhat is exactly idea for 10M memory there? Do it use whole memory for measurement or displayed lenght or what?How many samples there is on the image lenght. Perhaps 5k or less?What is wfm/s update rate in these images?Drop down memory as low as possible but still keep full samplerate with this same 500ns/div speed. (also after then stop scope and zoom out until trace is less than screen. Perhaps this way can estimate how many datapoints it show on the screen. It stronly looks like it use decimamion for show data points on the screen. Perhaps it is also reason to lack of intensity grading together with slow wfm/s speed.)As you can see in my images there is ERES on only in these images where it read in file name!Also measurements on in one image (last one), but I suspect also measurements as also displayed noise levels are not comparable due to different amount of data on the screen due very different wfm/s speed and different display memory handling and using foir measurements. Also we do not know details how these scopes exatly do measurements.If I set 14M memory and if display tell it use 14M memory this all data is on the screen, if display tell there is 7k lenght, it all is also on the screen. (if user want narrow window to whole data he can use window zoom). Very very different what GWI is doing. You can play some time with scope, run it example using different wfm/s speeds and you can seevisiblenoise (waveform fatness) is changing lot of.Also due to bandwidth difference it can expect around 4dB difference in noise levels what also can see in measured values. I do not know your 70MHz scope freq response using 1 or 2mV/div. SDS1kX measured BW is around 280MHz.

author: nctnico
author_rank: Super Contributor
timestamp: March 11, 2016, 11:24:32 am
content: Quote from: rf-loop on March 11, 2016, 07:25:00 amGW Instek isn't doing anything different than any other DSO. And no, your Siglent won't show all the memory either! At full samplerate and depending on the timebase the oscilloscope will have to show only part of the memory. For example at 500ns/div and 1Gs/s there is only room to fit 5000 samples in 10 divisions so you have to scroll left/right to see the rest of the signal OR change the timebase so more samples fit on the screen.QuoteThe 200MHz model of the GDS2000E series is in the same ballpark bandwidth wise. Hoewever there is very little use in focussing on the small details because the Siglent scopes fail in the big picture.

author: rf-loop
author_rank: Super Contributor
timestamp: March 11, 2016, 11:52:47 am
content: Quote from: nctnico on March 11, 2016, 11:24:32 amWhat?Do you have random generator on, or started friday too early?

author: nctnico
author_rank: Super Contributor
timestamp: March 11, 2016, 12:19:07 pm
content: Quote from: rf-loop on March 11, 2016, 11:52:47 amJust do the math and you'll see I'm right.

author: rf-loop
author_rank: Super Contributor
timestamp: March 11, 2016, 02:25:36 pm
content: Quote from: nctnico on March 11, 2016, 12:19:07 pmTracelenghtis 700pixel. And this is display width for captured waveform. And you know it as also I do.I repeat. If I set, even 14Mpoints memory datapoints lenght, whole trace lenght is still crushed to this display width. There is nothing outside display left or right border. But GWI I do not know. It looks GWI display is only small time slice from whole captured lenght, example if there is 10M memory in use and example 500ns/div in use with 1GSa/s. Capture lenght in this case is 20000 div and visible is only tiny part from it, 10div.Siglent SDS1kX display width is 14div and trace lenght is 14 divisions independent of selected and or used memory lenght. Example, If SDS1kX is using 14Mpoints memory lenght and 1GSa/s. Capture lenght is still 14 divisions, just screen width, nothing outside screen left or right border. And due to this, example noise looks visually different with same settings. More data, more noise peaks and more fat trace. But advantage here is that user have some knowledge about whole lenght and so also less visual blind time. Using window zoom user always see whole trace and then smaller time slice for details when need. This kind of scope need bit different working practice than this other principle scope. Both principles have advantages and disadvantages.After guite lot of use this kind of principle what is used in example older SDS1000 series or Rigol DS1000E series or many others including some Tek *) this principle what is used in example SDS1kX/SDS2k I feel strange and first I try find how hell I can set more memory for example 100ns/div speed. But, after short time when adapted to different working practice - I do not want change back. If I can wish something it is more vertical height for display for splitted screen.But, one like orange and one like jackfruit.*) in some scopes user can select, example in some Tek, if user want display all in screen width or ordinary way, small time slice and reest of lenght outside from display area. (If Sig can add this feature, of course it is nice)

author: nctnico
author_rank: Super Contributor
timestamp: March 11, 2016, 03:06:46 pm
content: Quote from: rf-loop on March 11, 2016, 02:25:36 pmBut when you do this then you'll see the timebase (s/div) is also changed because there is a fixed relation between samplerate, s/div and the number of samples used for the display. You cannot change the laws of physics!If you set the s/div to 500ns/div and have a samplerate of 1Gs/s then you'll have 500 samples per division. On a 10 division wide screen there will be room for 5000 samples so if the memory length is longer you'll have to scroll left/right OR change the s/div setting to see the rest of the signal.To get back to comparing the signals: with the same s/div setting and the same samplerate any DSO will show the same amount of samples per division (given the scope has enough memory to fill the screen). I know you want the Siglent to look better but it just isn't there because the settings of both your scope and my GDS2000E are 100% equivalent.

author: rf-loop
author_rank: Super Contributor
timestamp: March 11, 2016, 03:41:51 pm
content: Quote from: nctnico on March 11, 2016, 03:06:46 pmI do NOT want Siglent is better. Why hell I want it?But about capture lenght I can see that I can not explain it to you.I try last time. Siglent captured waveform lenght is same as width of display. There is nothing outside of display width. (exept in one tiny exeption) Period.If you can not believe this, then keep your religions. I keep facts, just as you want. I know well enough physics and enough math for this kind of kids things and nothing breaks these. Why you even try this kind of argument.

author: nctnico
author_rank: Super Contributor
timestamp: March 11, 2016, 04:44:15 pm
content: From your pictures it seems you let the Siglent oscilloscope choose a memory depth which results in the number of samples which fits the screen exactly. Other DSOs keep their memory depth at maximum and show a piece of the memory. That is the piece of the puzzle you are missing!What happens if you force your SDS1000X to a longer memory depth at 500ns/div?

author: markone
author_rank: Frequent Contributor
timestamp: March 11, 2016, 06:05:26 pm
content: Quote from: rf-loop on March 11, 2016, 07:25:00 amHere are the answers :- 10M is the deep memory size, in points, actually used- the measures are taken from screen data, i also have the option to use the whole buffer or the data segment between cursors- as nctnico said the scope's screen image is from 5000 (500x10) points extracted from capture buffer, this segment is selected by horizontal position knob and you can move it within the whole 10Mpts memory.- the refresh rate is pretty fast, i would say tens per secondThis scope is very responsive, the screen refresh rate sounds quite higher than mine Rigol DS1074Z, while the intensity grading is less spectacular.It has to be noted that its mainboard is totally different from what we saw with Dave GW's tear down videos, here we have a ZYNQ SOC interfaced to ADCs plus a Spartan-6 FPGA dedicated to screen display stuff.Quote from: rf-loop on March 11, 2016, 07:25:00 amThe scope's settings are from Wuerstchenhund's request :Quote from: Wuerstchenhund on March 10, 2016, 05:36:03 pmnot an absolute "recipe", but we have to start to use common settings if we want to obtain some fair comparing results.About "Perhaps this way can estimate how many datapoints it show on the screen." i guess every decent DSO is using a math method to adapt acquisition memory segment's data points to actual physical screen dot points and i would bet that GW does not do it with simple lossy decimation process, as you are assuming.I do not think that analyzing screen's dump files is the best method to follow, especially because i can often see that changing settings often does not change meas data while screen appereance actually mutates, and this would prove that the instrument is actually using a portion of deep memory to make meas (or whole, as for settings) and not screen's physical points, that in this case are much less.Quote from: rf-loop on March 11, 2016, 07:25:00 amI'm not sure to follow what you are saying, anyway i think that my answers cleared that.Anyway i'm wondering why you do not enable & show meas on your scope

author: rf-loop
author_rank: Super Contributor
timestamp: March 11, 2016, 06:19:21 pm
content: Quote from: nctnico on March 11, 2016, 04:44:15 pmNo. I know it exactly. And I have known this long time. It was same even in SDS2k demo. But it looks like there was something you did not realize. Just I told you that many other oscilloscopes works different and in some scopes also user can select between these modes.

author: rf-loop
author_rank: Super Contributor
timestamp: March 11, 2016, 06:47:14 pm
content: Quote from: markone on March 11, 2016, 06:05:26 pmOverall all ok and some question was just what I suspect but not know. (display related things)Also, btw, same in Sig, many settings what affect visible things on screen do not change measurement so I thing also sig do not measure from screen data (of course).There is also measurements in one image. (I do not know why you do not see this image). Problem with measurements is that I do not fully believe some things. Perhaps all is ok but until I'm enough sure and know more and also get some confirmations that measurements math works right I'm bit careful with these. Example with RMS there is some strange things in some special cases. I need raw acquisition and "hand" calculate and compare displayed measurements. I have some suspect that there is some error in some cases. Sadly I have not finded enough time for it.I have very limited times when I can do these playing things. Hobbies, work(s) and family life. All take time and quess what. In priority, one hobby is part of hobbies group and this whole group have lowest priority. Example just at this time I need two or more hours if I want meet Siglent scope and do any thing. And quite soon perhaps I have even less time for these hobbies. But some times ... and so on. If I can get 28 hour clock it may help some... now it is only conventional 24 hour...

author: markone
author_rank: Frequent Contributor
timestamp: March 11, 2016, 07:39:34 pm
content: Quote from: rf-loop on March 11, 2016, 06:47:14 pmSorry, i missed that because it was in attachment and not in post's "body" ( i'm still wondering if there is a way to do that in automatic way ...)It seems we are playing with similar cards, in the past i saw lots of much more expensive stuff doing a lot worse in this regard.I took in account the SDS1102X for a possible purchase but finally i went for the GDS-2072E due to meas bigger font size, good feedbacks from nctnico and also because i was intrigued by ZYNQ inside.The instrument responsivity exceeded my expectations (where it draws circles around the Rigol DS1000Z), the things that i do not like are rotary knobs encoders feeling, noisy fan (successfully replaced with a 60x60x15 Sunon Maglev) and intensity grading, where Rigol 1000Z wins hands down.

author: Performa01
author_rank: Super Contributor
timestamp: March 11, 2016, 11:50:32 pm
content: Different approaches to memory management – what a battle about DSO basics. Since RF-Loop acted as a brave knight but still didn’t seem to succeed in conveying his point, I’ll try to assist. Maybe I am able make it clear for everyone interested in the facts…While the basic operation of a DSO cannot differ between manufacturers and models, the more subtle implementation details do – and there are lots of them.One such thing is the usage of memory and what is reported on the screen. There are several options.Memory usage:1. Use the available memory for a single acquisition. They only display a tiny portion of it (what fits on the screen, e.g. 700 points) and let the user scroll through all the data after the scope has been stopped. These scopes usually have some scrollbar on the screen (even when fully zoomed out) to indicate what part of the memory is currently displayed and the waveform update rate inevitably is quite slow.2. Use the available memory for multiple acquisitions. Such scopes offer segmented memory and let the user scroll through all the individual acquisitions (i.e. trigger events) after the scope has been stopped. These scopes need some means to let the user select the memory depth in advance so that a certain number of segments can be obtained even on slower timebase settings – at the expense of sample rate as always, when memory is shortened. Such scopes don’t have a scrollbar on the screen but a history menu and the waveform update rate can be fast.3. Any (partial) combination of the before mentioned options, usually indicated by the presence of an ‘Auto’ setting in the memory menu. On auto, the behaviour matches #2 above, #1 otherwise.If a scope behaves like topic #2 above, there remains the question what happens once the data per memory segment exceeds the screen resolution, e.g. several Mpts captured but the screen is only 700 dots wide. In such a scenario, there are again (at least) two options:1. Data are just decimated. Without peak detect, narrow glitches might be lost even when the sample rate was sufficient to capture them.2. All data are displayed on the screen. No narrow glitches get lost as long as the sample rate remains high enough to capture them.I don’t know about GW-Instek. Just from the screenshots I’ve seen so far, the total lack of intensity grading together with the noise looking more like a freshly painted lattice fence, i.e. a clear geometric structure rather than a faithful representation of the real signal, isn’t too impressive. Of course I cannot know what settings have been used (and what would be possible), but it makes me wonder whether the acquisition unit of this scope actually is one of its stronger points.However, I can demonstrate how it’s implemented on a Siglent. SDS2000 and thus illustrate what RF-Loop tried to explain.Let’s capture a 10MHz / 3mVpp signal with a timebase setting of 50ns/div. Sample rate is 2GSa/s and memory used for one acquisition is just 1400 points. First screenshot in run mode (SDS2k_50ns_1400pts_run)Note that display type is dots and we still see a thick trace (due to noise) without gaps, as because of the fast waveform update rate we see a bunch of superimposed waveforms on the display. This of course changes in stop mode, where we can suddenly see the individual dots (SDS2k_50ns_1400pts_stop)In stop mode, all the noise is virtually gone as we now only see one single acquisition. It goes without saying that the gaps would disappear if I switched to vector display mode. This first demonstration shows how a fast screen update rate visually increases the number of dots displayed, as our eyes integrate over a number of individual acquisitions. But that was not the point yet.Up to now, the amount of data has been limited by the sample rate. For a total of 14 x 50ns = 700ns at a sample rate of 2GSa/s there are just 1400 samples available and that is only twice as much as the screen width. So in stop mode there were still gaps in the trace and we could not see clearly whether the entire data were displayedNow we change the timebase to 1ms/div and the signal frequency to 500Hz. Despite dots display mode, the trace looks even more solid than before (SDS2k_1ms_28Mpts_run)In stop mode, there are no gaps anymore, since all data have been overlaid in the screen memory. It looks pretty much exactly the same as in run mode (SDS2k_1ms_28Mpts_stop)So is this proof enough that all data make it to the screen? Certainly not, it just proves that it’s much more than just 700 points – but is it really all the data?To demonstrate this, with the very same settings as before, I’ve fed a narrow pulse ~5ns wide at a repetition rate of 5Hz into the scope. Without peak detect, this pulse would be missed most of the time if only a tiny fraction out of 28Mpts of captured data would actually be displayed. I’ve used color grading here just to aid visibility (SDS2k_1ms_28Mpts_5ns_pulse)Finally let’s go back to the 500Hz sinewave and lower the memory by a factor of 100, which drops the sample rate down to 20MSa/s. Still no difference between run and stop mode, but because of the slow sample rate the trace gets thinner, i.e. showing less noise as is to be expected (SDS2k_1ms_280kpts_stop)

author: nctnico
author_rank: Super Contributor
timestamp: March 12, 2016, 12:51:02 am
content: Quote from: Performa01 on March 11, 2016, 11:50:32 pmSorry but RF-loop isn't making a point at all. Your remarks about memory usage are what I have been pointing out all along but he doesn't seem to get it.QuoteActually the way GW Instek does intensity grading is far better from a useability perspective. It doesn't go from 0% to 100% but starts at an offset (depending on the trace brightness setting). This makes a lot of sense compared to blindly simulating analog scope behaviour. The biggest drawback of an analog scope is that occasional pulses and spikes aren't very visible because of the large contrast between them. By having less contrast between minimum and maximum brightness (which a DSO can do and an analog scope cannot) you see more of the signal. And yes, this makes a trace with noise look thicker but the whole point of a DSO is to make a signal visible in a better way than an analog scope. IMHO it is a big plus of the GW Instek to display the signals the way it does. BTW the fact you need to use color grading on the SDS2000 to show a narrow pulse makes my point very clear

author: Performa01
author_rank: Super Contributor
timestamp: March 12, 2016, 01:56:54 am
content: Quote from: nctnico on March 12, 2016, 12:51:02 amOh really? Sorry, I’ve totally missed that.QuoteThat offset appears to be 100% on the GW Instek.Every DSO has to have some offset, depending on the number of intensity grades. With e.g. 32 grades, the minimum offset would be 3.125% obviously. And it should come as no surprise that it depends on the brightness setting of the scope screen what we actually get to see.QuoteIntensity grading is there not just for the sake of emulating an analog scope, but because it provides one more dimension of valuable information that analog engineers will appreciate.It’s different for digital bus decoding of course – that’s why logic analyzers don’t have intensity grading.QuoteThat’s one occasion where color grading is a nice alternative, isn’t it?I haven’t heard of anyone having difficulties viewing a signal on a scope with proper implemented intensity grading. But it can happen when viewing a screenshot on a computer monitor with quite different settings than a DSO screen.Anyway, no need to discuss what you or I particularly like in a scope. Everyone can look at the screenshots and draw their own conclusions.

author: c4757p
author_rank: Super Contributor
timestamp: March 12, 2016, 02:19:14 am
content: I love how every single mention of Siglent on this forum turns into an argument.

author: Monkeh
author_rank: Super Contributor
timestamp: March 12, 2016, 02:27:22 am
content: Quote from: c4757p on March 12, 2016, 02:19:14 amIt's fantastic. And there's always one very loud, bordering on rude voice in there..

author: markone
author_rank: Frequent Contributor
timestamp: March 12, 2016, 03:34:55 am
content: Quote from: Performa01 on March 11, 2016, 11:50:32 pmIMHO this approach would be appropriate if the discussion seemed among retards, but it's not the case and i include everyone.Personally i'm not here trying to demonstrate who is the winner among these scopes, i'm only reporting facts that could be usefull to whome are wondering about GDS-2000E line features.Intensity grading sure is not the strong point (maybe it's the last one) it's enough to say that the firmware disables it for timebase equal or lower than 50ns/div, who is looking for a sensational analog simulation must avoid this scopes, but the "acquisition unit" is not so poor as you are assuming.The strong point is the computational power, maybe the best for this price point (i paid mine 450E plus VAT), the way it performs FFT function shows it clearly together the waveform refresh rate, overall UI responsivity (also @ 10Mpts), screen dump to USB flash memory in .png format (lighting fast) and so on.System stability is also very good, i used it hundreds of hours without crashes.For the price i think it comes with a fair amount of options, including serial interface decoding working on whole deep memory buffer and front end noise floor seems on par with Siglent 1202X, pixel less... pixel more ...I will attach some screens to show some of acquire's section options.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: March 12, 2016, 10:11:04 am
content: Quote from: c4757p on March 12, 2016, 02:19:14 amThat's no surprise, Siglent is somewhat contentious. On one side they offer some low cost kit with nice features (on paper at least) and have shown that they can produce really good quality hardware, on the other side they come up with silly nonsense like this "unsolicited customer letter" that essentially says they assume their cutsomers to be complete morons, they lie, they cheat, and they have shown again and again that they are completely incompetent when it comes to software. That the most voiceful proponents of Siglent are actually Siglent resellers is also quite telling.And basic functionality often is an issue when it's about B-brand low cost scopes which pretty much all have some bugs, flaws and quirks. That's pretty much why they can be so cheap.

author: Performa01
author_rank: Super Contributor
timestamp: March 12, 2016, 02:26:29 pm
content: Quote from: markone on March 12, 2016, 03:34:55 amI don’t quite understand what you mean here, but I have the uneasy feeling there is some misunderstanding (again?).By ‘approach’ I was regarding to the way manufacturers implement memory management in their scopes.RF-Loop was talking about how the Siglent approach makes all captured data visible on the screen, hence no decimation. I was under the impression that someone denied this. In this situation I thought some well documented demonstration including screenshots would help everyone interested in the topic to decide what’s actually going on. No more, no less.QuoteYes! You’re very welcome!If you’ve ever seen my review of the SDS2000 V2 firmware, you’ll probably conclude that is my approach also. I just document the features, including all strengths and weaknesses (and bugs of course) and do not try to turn the shortcomings into desirable features.QuoteThat sounds fair. Nothing is perfect in this world.Regarding acquisition I just voiced my impression, but at the same time I also said that I don’t know about the settings and capabilities. That’s also a matter of presentation.If I get to see a trace that looks like a solid comb, i.e. more like crosstalk from a digital bitstream rather than noise, then that simply doesn’t impress me. All the more so as the discussion was about noise, and hopefully we can agree that visible noise is affected by the amount of displayed data. And since the trace looks the way it does, it is evident that there’s very little data – in fact just one single acquisition, not nearly enough to faithfully represent the real noise.The amount of data is affected by timebase, sample rate and – last not least – the way the captured data is represented on the screen, e.g. whether it’s decimated or not. This is where the latest debate started.Apart from the visual impression, there’s also the automatic measurements, which appear to be the more objective criteria. But here again, it depends what amount of data is used. The more data, the higher the pk-pk reading for noise.All that said, I agree with an earlier statement of yours: Both scopes are in the same ballpark, noise isn’t an issue on either of them. So even though this debate appears moot, it still can be helpful in understanding how individual scopes work, don’t you think?QuoteThis is certainly true and vice versa the post processing power appears to be the weakest point on the Siglents. But UI responsivity is certainly not a problem there either.QuoteWell, that goes without saying. Except for early Windows based scopes, I’ve never heard of one crashing.QuoteFully agree. And if you’re content with your scope, I share happiness with you!I’m not the one who jumps into every thread about an Instek (or any other) gear just for bashing it and trying to make any of my own crap look superior.QuoteNice screenshots, thanks for that.Makes me curious:What’s the maximum segments you can have?What hides behind the ‘Analyze Segments’ ?

author: Performa01
author_rank: Super Contributor
timestamp: March 12, 2016, 02:28:57 pm
content: Quote from: Wuerstchenhund on March 12, 2016, 10:11:04 amSad, but true.

author: nctnico
author_rank: Super Contributor
timestamp: March 12, 2016, 04:58:42 pm
content: Quote from: Performa01 on March 12, 2016, 02:26:29 pmThere is not much to bash about GW Instek because their stuff works as specified. Siglent on the other hand needs years to get their firmware in a usefull state and even then it has bugs they will probably never fix (log sweep on the SDG1000 series for example). The difference in useability between the Siglent SDS2000 I used to own and the GW Instek GDS2000E is like night and day. Perhaps I'm biased because I still feel Siglent has cheated me out of approx. 2000 euros but then again if the SDS2000 was somewhat useful I would not have bought the GDS2000E at all (and -more or less- binned the SDS2000 in the process)!BTW Siglent Technologies America also received an unsollicited e-mail from me to complain about the SDS2204 but somehow that never made it to this forum or other customers

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: March 12, 2016, 06:44:14 pm
content: Quote from: Performa01 on March 12, 2016, 02:26:29 pmTry a newer Tek

author: markone
author_rank: Frequent Contributor
timestamp: March 13, 2016, 12:21:28 am
content: Quote from: Performa01 on March 12, 2016, 02:26:29 pmUp to 29000, time tag resolution 4ns.Of course the max number depends on record lenght, as follow :Record length Number of segments1000 pt. 1 ~ 2900010k pt. 1 ~ 2900100k pt. 1 ~ 2901M pt. 1 ~ 2010M pt. 1 ~ 2Quote from: Performa01 on March 12, 2016, 02:26:29 pmStatisticsandMeasurement Listfunctions, performed on stored segments data, to be honest not yet used, but they seem quite handy.In attachment a user manual extract for Segment Analysis.

author: markone
author_rank: Frequent Contributor
timestamp: March 13, 2016, 12:52:11 am
content: Quote from: nctnico on March 12, 2016, 04:58:42 pmAlmost surely you have already explained that elsewhere, but what bugs were decisive to make this scope useless for you ?SDS2000X scopes are on the market from a while but AFAIK no previews / reviews are available on the web, as well as for new SA3000X ... i found it a little bit weird.For the SA the EEV Siglent rep. provided some justifications regarding ongoing TG modifications, no idea for the new scope line.

author: nctnico
author_rank: Super Contributor
timestamp: March 13, 2016, 01:23:32 am
content: Quote from: markone on March 13, 2016, 12:52:11 amMany. The most important ones with the V1.x firmware; here is part of my unsollicited e-mail to Siglent sent 10 months before the V2 firmware got released:- High resolution mode absent- The averaged signal (thin trace) dissapears in 'stop mode' and gets replaced by a 'furry' non-averaged trace; not useful because it doesn't allow to freeze an averaged signal and do measurements with the cursors.- Protocol decoding only decodes what is on screen. Zooming in on a stream of messages by changing the timebase doesn't work and the zoom function is disabled. This makes protocol decoding practically useless for looking at malformed 'bits' and/or zooming in on parts of a message.- Protocol decoding doesn't work on digital channels. Having protocol decoding on digital channels was one of the reasons for me to buy the SDS2204 (someone from Siglent confirmed decoding would work on digital channels on EEVblog).- FFT is not useful without post-processing like averaging to clean up the signal. Also 1024 points are not enough.- The cursors work terrible in version 1.1.37.2 (they go through the sequence of x1, x2, x1+x2, y1, y2, y1+y2).- No measurements while decoding- No zoom for digital signals- Peak-detect doesn't work in roll mode- SCPI over LAN doesn't work which makes the LAN connection useless. I tried sending commands over the LAN but the oscilloscope doesn't respond to commands requesting waveform data.- Sometimes the colors of the 4 analog channels all turn yellow. Changing modes eventually fixes that.- Over all the functions are hard to combine like zoom & digital, zoom & protocol decoding, measurements & digital, measurements & decoding, etc.- CAN triggering doesn't work- RMS is not calculated over a cycle / no cycle RMS measurementSince then Siglent has come up with a new V2 firmware version which pulls the 1000X and 2000X firmware together but that seems to be just as useless due to features being just checkbox features like decoding only what is on screen, short FFT and the short Eres memory.In contrast: GW Instek fixed some bugs I found within 4 weeks!

author: rf-loop
author_rank: Super Contributor
timestamp: March 13, 2016, 10:19:12 am
content: Quote from: markone on March 11, 2016, 07:39:34 pmAfter more deep inspections it is clear that in this my original message this image RMS value is NOT ok for this purpose what it is used here. It can not use for characterize this random noise. It can not see well in this one image but it is RMS what include (of course) also DC. If delete DC offset and set this noise center to zero, then we have this noise itself RMS and it is more or less different. So, it is RMS (power) from signal what have AC component (noise) + DC component (internal DC offset error in this case). If we measure oscilloscope noise, this RMS may give really false result. Of course it is true power if math is ok but about noise it may give, depending DC offset, false result as some kind of misapply (as long as there is DC offset)This can analyze more if take raw ADC data and look how far noise middle is from zero. Perhaps also some GW Instec measurements suffer this same "error".I have also made other measurement. With external noise source + DC bias. It looks like RMS measurement itself is ok. But, for characterize noise alone, it is usable only in case there is zero DC bias noise for RMS, or if we remove DC effect from result.Of course this error is only barely visible in this one image but more clear if use 1mV/div or 500uV/div and specially if scope have high DC offset (due to example thermal DC drift in front end)

author: markone
author_rank: Frequent Contributor
timestamp: March 13, 2016, 11:33:12 am
content: Quote from: nctnico on March 13, 2016, 01:23:32 amHi nctnico,thank for detailed bug list, time ago i considered Siglent SDS2000X scopes for purchase, but the complete lack of web review and all the fuss around the SDS2000 line prevented me to go farther in the process.

author: markone
author_rank: Frequent Contributor
timestamp: March 13, 2016, 12:23:19 pm
content: Quote from: rf-loop on March 13, 2016, 10:19:12 amI can confirm that, DC component falls straight into RMS meas value also for this scope, but i do not consider it an error, it's the root mean square of all data samples as stated in the user manual.I'm aware that we are far from a serious noise floor assessment, but as already said, it seems that we are playing in the same ballpark, if we want to go deeper, we can open a dedicated thread.Returning to the main topic, if theunsolicited email about the unsolicited emailis genuine, i'm starting to think that we have an east/west cultural barrier problem that distorts the original intentions.Having had an experience with an important power electronics firm based in Taiwan, i learned that they have a huge difficult to admit their jobs bugs/faults to the point to come to deny the evidence.And what i really i do not undertsand is why well equipped instruments (for the price) like SDG2000X (that i own) and SDM3055 (both on the market for several months) are still soffering for a bug like not recover last setting on reboot with specific option turned on.The thing was recalled here and there tons of times, but Siglent seems to utterly ignore the impact that such a bug could have on overall equipment perceived quality.What the hell cost them fix it asap ?Sometimes it's like to do most of the job and stop leaving out some small but important details that prejudice the whole product image.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: March 13, 2016, 01:02:33 pm
content: Quote from: markone on March 13, 2016, 12:23:19 pmIf that letter is genuine then I'm Santa ClausIt's a cheap attempt to come up with some positive "reviews".QuoteYeah, that's true with many SE Asian cultures. In my experience, Japanese are the worst in that regard, probably because bugs/faults are seen as personal failures of whoever was responsible for that area.QuoteQuite a bit. The reason the kit is so cheap and still well equipped is because they cut corners somewhere. And for products like these lots of cost savings can be made by foregoing software QC, testing and support.You have to ask yourself: are you willing to pay say 30-60% more if the firmware/software was much more mature and bugs would be fixed quickly? I doubt many would, as it pushes Siglent kit a lot closer to other alternatives price-wise.QuoteThe thing is that software QC and testing isn't small and unimportant, it's actually a very large part of what makes a modern AWG or DSO. Software testing is also much more complex than testing most hardware assemblies (a rule of thumb is that each additional Line Of Code potentially doubles the number of bugs). Doing it properly costs a lot of time and money.I do agree that Siglent could invest in better software QC and testing, and make sure product firmware is reasonably mature before a product is thrown to the market. But it's clear they have decided to not invest and just ride it out, selling as much as they can while keeping costs at a bare minimum, and using morally and legally less favorable methods to manipulate their public image.

author: rf-loop
author_rank: Super Contributor
timestamp: March 13, 2016, 01:44:12 pm
content: Quote from: markone on March 13, 2016, 12:23:19 pmYes.And as also I told it is not error. (only what I bit suspect or think was about GWI, jus because I did not know how it is implemented in GWI and never tested anything with it.)"Error" is more like "user error" = misapply IF user use this value for characterize oscilloscope front end natural noise without take account this fact that it include DC bias if DC bias exist in system (and if RMS math is without error).As we know here in forum is lot of not so well experienced peoples who may drop to this kind of trap. This is also why it so important to think what we see in captured waveform on the screen and not only "blind" look numbers as facts if we do not also thing what all is "inside" this numerical "fact". It was first ten seconds I look SDS screen and noise and mesurement results and I know something is wrong. My eyes tell that this RMS is not possible with this image. So, this was also original reason why I did not take all measurements to all images - because I did not trust these numbers and this time total lack of time t do any more tests and look what is behind this. Only know that something looks like visual noise + DC power but when can not be sure, it is best to avoid false data. (in this one image I made selfcal and carefully look DC bias is not so high so "error" for true noise RMS is not huge.Here examples. Not about scope front end noise but tested with external noise source with different bias. (reason for gated measurement is for other reason. Who do not know what it is, it mean that data for measurements are collected only from area between gate borders A and B))Signal is noise what RMS is 100mV without DC. Then added 100, 200, 300, 400 and 500mV DC bias.This is only for common information to some peoples who wonder these RMS numbers and scratch they head, and this have nothing to do for which scope is good or bad.

author: nctnico
author_rank: Super Contributor
timestamp: March 13, 2016, 01:45:10 pm
content: Quote from: markone on March 13, 2016, 12:23:19 pmIMHO a lot has to do with the inability of Siglent to manage software development and doing proper systems engineering (how software should work). When looking at Siglent equipment it seems they have several teams working in parallel without sharing knowledge or common code between them. For example the restore-on-power-up feature was introduced on the SDG1000 series last year or so. It seems their basic software platform is different for each product (IOW: one big mess!) so they can't copy common functionality to another product very easy.

author: nctnico
author_rank: Super Contributor
timestamp: March 13, 2016, 01:50:33 pm
content: Quote from: rf-loop on March 13, 2016, 01:44:12 pmJust let the scope warm up properly and run the SPC (signal path calibration) before taking the measurement. Problem solved.

author: rf-loop
author_rank: Super Contributor
timestamp: March 13, 2016, 02:14:42 pm
content: Quote from: nctnico on March 13, 2016, 01:50:33 pmIt do not work until scope is well warmed? (sorry but I believe it works what ever is scope temp) Or why here is DC bias? Or at this time you did not know it?@nctnicoSo, for what reason there is RMS value. For show noise RMS or for what? (or do you want to create the impression that GWI have more bad noise than it really have, if someone look this RMS number without enough experience to know what DC bias really do)

author: nctnico
author_rank: Super Contributor
timestamp: March 13, 2016, 02:37:37 pm
content: When doing low voltage DC work you should let your oscilloscope warm up properly because some thermal drift in DC offset is unavoidable (and also the reason SPC cannot be run until an oscilloscope and many other equipment has been on for at least half an hour). I made the screenshot above in a hurry so there is some DC offset in there. In the later screenshot (with the lower value) the scope did have time to achieve thermal equilibrium and hence the DC offset calibration is correct. RMS is usefull to get an idea about the amount of energy in the noise besides the peak-peak value.

author: rf-loop
author_rank: Super Contributor
timestamp: March 13, 2016, 02:45:02 pm
content: Quote from: nctnico on March 13, 2016, 02:37:37 pmDo you try to tell that you do not know what is RMS. In your image there is RMS but it is NOT from area between p-p visible and measured values. It is, IF there is zero DC bias. It is hard to believe you happy jump over this fact.

author: nctnico
author_rank: Super Contributor
timestamp: March 13, 2016, 03:15:55 pm
content: Quote from: rf-loop on March 13, 2016, 02:45:02 pmI already told you: I made the screendump in a hurry and did not let the oscilloscope warm up properly so the Vrms measurement is slightly off. Well spotted but it is easy to correct for the DC offset since Vrms=sqrt(Vdc^2 + Vac^2) (where Vac typically is an integral over a complex function) -> The DC offset is about 100uV so 135uV = sqrt(100uV^2 + Vac^2) solve this and you'll find the Vac^2 term contributes 68uV to the RMS value which is about right compared to my other measurements with 0 DC offset after letting the scope warm up.

author: rf-loop
author_rank: Super Contributor
timestamp: March 13, 2016, 03:40:49 pm
content: Quote from: nctnico on March 13, 2016, 03:15:55 pmGood, now it is back on the road.Here we can see SDS1202X noise level using full BW.Note Ch2 RMS in statistics.(note: Current on the statistics and bottom measurements row have small time difference when values are updated so always current values are not just same when save image to USB from fast running scope.)CH2, ("zero" DC bias) RMS 79.6uV and p-p as in image, around 700uV (full samplerate so not need peak peak mode). BW full,( nominal 200, measured 280MHz). Scale 1mV/div (not digital zoom sensitivity like in GWI. Siglent have real full resolution down to 500uV/div)(As can see CH1 is biased with around 500uV DC and this here imaged for example to show in real world how careful unexperienced oscilloscope users need be with numbers specially if it is not clear what these numbers really are)

author: rf-loop
author_rank: Super Contributor
timestamp: March 14, 2016, 08:56:44 am
content: Quote from: markone on March 13, 2016, 12:21:28 amWhat is maximum segment/s speed (example if use 1000pt segment lenght)?I can not find this information.

author: femtohertz15
author_rank: Contributor
timestamp: March 14, 2016, 07:42:43 pm
content: Hey, just for grins could someone take a nice cell phone photo of one one those test case ~1mvpp sines on a Tek 2246 and/or 2465 ?

author: nctnico
author_rank: Super Contributor
timestamp: March 14, 2016, 08:16:08 pm
content: Quote from: rf-loop on March 14, 2016, 08:56:44 amMy guess it is the same as the maximum waveform update. Then again segmented recording is mostly useful for events which don't happen very often. If events happen often it is easier to record one long trace.

author: tautech
author_rank: Super Contributor
timestamp: March 15, 2016, 12:08:27 am
content: Quote from: nctnico on March 14, 2016, 08:16:08 pmReally?Isn't that what an advanced trigger suite is for?

author: nctnico
author_rank: Super Contributor
timestamp: March 15, 2016, 12:58:11 am
content: There is the trade-off between having all information in one trace or using segmented recording. If you want to decode several messages in a stream where they follow quickly (for example the initialisation of an ADC) there is not much use of setting up triggering etc if you can press the stop button or use edge trigger on the first edge. However if messages only appear once per second then segmented recording makes sense where I would typically try and capture a burst of messages (command/response pair) in one segment. All in all when you get at the point where you run into the speed limits of segmented recording then you are probably already past the point where it makes more sense to record everything in one trace.

author: markone
author_rank: Frequent Contributor
timestamp: March 15, 2016, 01:59:40 am
content: Quote from: tautech on March 15, 2016, 12:08:27 amNot sure about what you mean, but if you want to store several "sporadic" signal events you need in any case a segmented waveform capture function, advanced trigger mechanism could be also combined.I do not have an answer for your question right now, i will try to arrange some test to understand if it sustains full speed as said by nctnico.

author: rf-loop
author_rank: Super Contributor
timestamp: March 15, 2016, 06:04:36 am
content: Quote from: markone on March 15, 2016, 01:59:40 amIm not sure what is this @tautech question. Is it (trigger) somehow about this:(GDS 2000E manual pages 85-86 explain segmented memory)Quote from: GDS 2000E User manualI do not know how Good Will Instrument jump over trigger re-arm time. Perhaps it is superfast if there is method for jump over whole trig re-arm, but Keysight scopes need trigger re-arm time, also cheap Siglent need, and here depending model.Re-arm time, Keysight InfiniiVision and Siglent 1000X and 2000X oscilloscopes.(minimum timebetween trigger events)Keysight 3000 and 4000 X-Series: 1 usSiglent 1000X and 2000X series: 2 usKeysight 5000, 6000, 7000: 6 usKeysight 6000 X-Series: 7.5 usKeysight 2000 X-Series: 20 usJust this is one important thing in true segmented memory acquisition. Reduce time gap between segments compared to normal capture with quite long (blind) time before next waveform can acquire. Between segments, oscilloscope do not time consuming processing between acquisitions and because this, typically maximum waveform(segment)/s speed is higher than normal acquisition. Of course in many applications do not need maximum speed, specially when we inspect known signals what have long time between occurence what we are interesting.If I have 50ns pulses repeating 1ms interval and I do not want know if there exist also some extra between these pulses I do not need fast segmented mem acquisition.with 1ms interval there can get example 29 second (29000 pulses) using max samplerate. If want use one long memory capture this case need 29 Giga points memory. Now it can do with segmented memory. This case do not need fast segmented memory, just like what ever toy "frame recorder". But if after this 50ns pulse there is some glitch after example 5us. I loose it if speed is not enough.But what if need capture say example 29000 pulses and example 50ns pulse width but pulses interval is say example 3us. If capture it to continuous memory it need 87M points memory. But in this case segment/s speed is 333ksegment/s.In some cases pulse interval is modulated so that minimum pulse interval is quite short, say example 1us but maximum interval is 1000us. For this kind of signal we need If modulating frequency is say example 0.2 Hz or something like it, we need fast segmented memory acquisition with enough segments. (Yes, Siglent can NOT do this but it can if minimum time interval is equal or over 2us)How to simply test segment speed.Take example 50MHz signal so that trig is reliable. Start segmented acqquisition and after it have captured enough segments. Just look segments time stamps over example 10000 segment interval. (Also look that there is not any significant time gaps (time jumps) in table)Also it is good to check from Trig Out if can use second scope. (example there can easy see if there is anomalies in speed)Just for reference here is Siglent 1000X speed table (including total memory amount for segments) with maximum samplerates (1GSa/s 1Ch and 500MSa/s for 2 channels simultaneously)Add for amount of max segments (1CH in use, 1GSa/s): 200us/div 18 segment each 2.8M, 500us/div 6 segment each 7M and 1ms/div 2 segment each 14M.

author: femtohertz15
author_rank: Contributor
timestamp: March 15, 2016, 08:47:57 am
content: From my Tek 2235, 2mV/div, 20us/div, full BW, TV Line trigger to reject switching PS noise in my cheezy $15 DDS function generator.

author: rf-loop
author_rank: Super Contributor
timestamp: March 15, 2016, 09:16:40 am
content: Here Tektronix 2445B (as asked, image using phone)1.6kHz, around 500uVpp sine from Siglent SDG. (Narda 12GHz 20+20dB attenuator between scope and generator)Trace vert position is set for around 1mV up from center line just for better visibility.(yes, there is also offset error if look carefully, scope take from "cold store" and last cal with adjustments very very long time ago. -0.4mV on the display, just forget it.)

author: markone
author_rank: Frequent Contributor
timestamp: March 15, 2016, 11:39:30 am
content: Quote from: rf-loop on March 15, 2016, 06:04:36 amWhat i can do right now is to report what user manual says in this regard :Also notice that the scope doesn’t need torearm the trigger between each segment, this makes the segmentedmemory function especially useful for high speed signals.

author: rf-loop
author_rank: Super Contributor
timestamp: March 15, 2016, 11:53:18 am
content: Quote from: markone on March 15, 2016, 11:39:30 amYes, this was quoted previously in my msg where I wonder this.What is minimum time between trigger events we do not know and this is question.In Siglent it is 2us as in table where is also Keysight scopes. Some manufacturers tell what is minimum time gap between segments (as example some LeCroy if I remember right). In Siglent it is 1.3us.Trigger interval you can measure easy. Turn scope on, segmented memory mode on. Minimum segment size (I think it is 1k) and input 50MHz. Select example 10001 segments for use.Run it and take time stamp table open and look how much time is from first to last segment and divide by 10000. This give rough estimate but it do not tell if there is variations inside whole sequence segment to segment time.. But still it give good average.

author: femtohertz15
author_rank: Contributor
timestamp: March 15, 2016, 12:05:57 pm
content: Looks good, rf-loop.

author: rf-loop
author_rank: Super Contributor
timestamp: March 17, 2016, 07:12:45 am
content: Quote from: markone on March 15, 2016, 11:39:30 amI have now tried search information about GDS2000E. There is things that this scope serie is interesting, specially its FFT looks very interesting at this time.What I know now, intensity gradation is extremely poor and limited.It do not have real 1mV/div sensitivity. Lowewst true is 2mV/div. But, noise figure is acceptable.FFTis or looks like very strong and it looks it have lot of post prosessing power also. And THIS feature is why I'm quite interest about this model.But what I do not know.>Waveform update rates with different time bases etc. Only real is that on the specs sheet / brochure there read 120000wfm/s.I have not seen any tests about wfm/s speed. Hope some one turn scope and and write down some values with different scope settings.>Segmented memory real speed. Nothing. And if scope settings (other than segment size and t/div and number of channels) affect it, something about it.>Mask test speed. With different settings if speed is not same as all wfm/s speeds. (also in case that result pass or fail)It feels strange that output pulse width is 500us and manual tell that it give pulse for every time test fail. Igf it is true, then it is like joke.Also I do not have seen any trigger jitter results in full window and window zoom and not with long delays.This thread is not best for these but lets hope we can see these where ever is right topicI can not find here locally any place where I can go and look this scope.

author: markone
author_rank: Frequent Contributor
timestamp: March 17, 2016, 10:34:45 am
content: Quote from: rf-loop on March 17, 2016, 07:12:45 amhttps://www.eevblog.com/forum/testgear/gds-2072e-1mpoints-fft-gt-i'm-impressed/msg867725/#msg867725There is also dual screen FFT option, but with current firmware version is disabled.

author: nctnico
author_rank: Super Contributor
timestamp: March 17, 2016, 10:13:13 pm
content: Quote from: rf-loop on March 17, 2016, 07:12:45 amA pulse of 500us wide is already hard to detect in an automated test setup using a PC and a simple digital I/O interface. Making it even shorter would make the mask-test output signal more or less useless. What you want in a mask test feature for automated testing is for the scope to be good at detecting an malformed signal and provide an output pulse which is long enough to detect.Anyway, this thread has already addressed all the points from the e-mail in the first post and I think it is clear whoever wrote that doesn't know much about operating a scope. If I where you I'd get a (newer) GW Instek scope and I'm quite sure you'll find it has many advantages over the Siglents where it comes to the more advanced features. I wouldn't be surprised if you end up becoming a GW Instek dealer!

author: rf-loop
author_rank: Super Contributor
timestamp: March 18, 2016, 06:15:08 am
content: Quote from: nctnico on March 17, 2016, 10:13:13 pmtrue average wfm/s speed with different timebases?(and with GW, due to memory lenght and displayed part of it, visual blind time also?)Segmented memory acquisition max speed with different settings? Or are there at all fast segmented memory acquisition?Pass/fail mask test speed? (also one handy tool for finding signal exeptions, if it is fast enough, and not only for test automation for get go/nogo signal out where many times also slow speed mask test is well enough)Due to some reason we do not know nearly anything about these.Always backround running history? (stop and look what happend before stop, up to 80000 previously captured waveforms). This I know, GW do not have.QuoteFor what? I have very limited time for these hobbies.Thenhttp://www.xilinx.com/publications/prod_mktg/zynq7000/goodwill-casestudy.pdfQuote from: Xilinx, GW Instek and Xilinx pdfWhat? What are these "previous product line" what have been 10000wfm/s before they change to Xilinx ZynqGDS2000A claimed 80000wfm/sGDS1000B claimed 50000wfm/sDo they now tell truth that old claims have been lies or what is this?No later than now would be good to get the facts on the table about wfm/s speeds.Then something really weird. What are they smoking?Quote from: Xilinx.......pdfReally? What is this doing with change to Xilinx Zynq. Its looks like it is just simple digital zoom from 2mV/div what who ever can do, done even in cheapest Rigol. It have seen in many scopes far from history. Also real 1mV/div. Also 500uV/div.

author: nctnico
author_rank: Super Contributor
timestamp: March 18, 2016, 09:18:37 am
content: Quote from: rf-loop on March 17, 2016, 07:12:45 amSell products which work, have in less (unhappy) customer returns and deal with a manufacturer which actually listens to their dealers!Quotewfm/s speed is totally irrelevant and a marketing number hyped by Keysight! What you need is good triggering and other goodies. Waveforms per second is an utterly meaningless number because you'd need to stare at the oscilloscope screen continuously (no blinking!) to see an event. Nobody uses an oscilloscope that way. The way people find 'glitches' in a signal is by setting a trigger for abnormalities in a signal (and do something else). On some occasions I have let my logic analyser run for a day with a specific trigger setting to check if there is still a glitch. I'm not going to sit in front of it and watch it during such tests.

author: rf-loop
author_rank: Super Contributor
timestamp: March 18, 2016, 11:25:04 am
content: Quote from: nctnico on March 18, 2016, 09:18:37 amPerhaps this is not Hewlett-Packard/Agilent/Keyshithttp://cdn.rohde-schwarz.com/pws/dl_downloads/dl_application/application_notes/1er02/1ER02_1e.pdfOf course there is maany methods, all these have pros and cons. You name one method. Setting trigger for undefined anomaly in signal.Quote from: R&S pdfFor undefined/uncnown glitch or other unwanted anomaly, in worst case also rare, I do not want siith hours with slow scope iterating what is working trigger function and its settings.I will use enough fast scope using persistence, fast mask test etc... after I find what is going on there I may in some cases find reliable trigger for some rare random anomaly... perhaps. Anomaly may be also random form and randomly exist, also sometimes rare.Btw, if shortest memory is 1k and we use 10ns/div speed. There is 100div. But you see on the screen only 10%. If t/div is 1ns/div you see only 1% and 99% is unvisible. This is one important part of blind time (this part of visual blind time do not exist in Siglent SDS1kX and SDS2kX). Other is more or less time what need wait for next possible trig. Whole this waiting time we are blind what happends there.If Agilent is wrong...ok lets Agilent be wrong. If Rohde&Schwarz is wrong let them be wrong. All we know who is always right. He is here.. on the EEVblog. We do not need fast wfm/s in segmented acquisition - why- Because GWI do not have. We do not need fast mask test - because GWI do not have. We do not need know even wfm/s update rate - Because GWI do not know...We do not need intensity gradation because GWI do not have.What other things we do not need.I know. We do not need oscilloscope at all if all our signals are enough well known and our DUT works perfect.So, use only well working things and you do not need oscilloscope at all.Also if you design and build something. Do perfect design and build work and you do not need oscilloscope at all for inspect problems.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: March 18, 2016, 12:04:57 pm
content: Quote from: nctnico on March 18, 2016, 09:18:37 amI have to agree with nctnico here, with a good modern scope there's no need to sit there and stare on a persistence screen to find glitches like back in the old analog days.Quote from: rf-loop on March 18, 2016, 11:25:04 amThat's true if you use an R&S or Keysight scope (and R&S overuses update rate for their RTO scopes as much as HPAK does), but LeCroy's mid-range and high-end scopes (including the Siglent-made WaveSurfer 3000) have something called WaveScan which finds any glitches and anomalies in a signal, even so if the signal is changing. There's no "learning" or "manual intervention" involved during the scan, and it's pretty easy to setup.There's a very old (2010!) short video on Youtube demonstrating an older version doing a more specific search:https://youtu.be/Ax4Fwj7jagUBut even on other scopes that don't have something like that you can find glitches quickly by using a thought-out approach and advanced triggers. There's no need to sit there with mask test (which works if the signal is not changing anyways) and persistence and wait for some problem to appear.But of course advanced tools are often not available for entry-level scopes...

author: markone
author_rank: Frequent Contributor
timestamp: March 18, 2016, 01:42:26 pm
content: Quote from: rf-loop on March 18, 2016, 06:15:08 amI'm not convinced about that, owning both GW2072E & Rigol 1074Z i made some comparison tests in this regard, GW clearly wins hands down.In attachment screenshots for 10Khz sine wave 1mVrms @ 1mV vertical scale, 10Kpts for GW and 12Kpts for Rigol :

author: rf-loop
author_rank: Super Contributor
timestamp: March 18, 2016, 02:07:13 pm
content: Quote from: markone on March 18, 2016, 01:42:26 pmAs I write long time ago, Rigol DS1000Z do not have real 1mv/div but also I have quite strong suspect also its 2mV/div is not true resolution. (Previously I own one Rigol DS1000Z so I have also investigated it and not only imagine in mind)Now your image give more evidence about this joke.As can easy see, GW have done only 2x zoom but Rigol 5x zoom (from 5mV/div) + Rigol have really terrible random noise + quantization due to zoom more, perhaps from 5mV/div... If Siglent perhaps win GWI with noise, or not, but they are roughly still on the same road. Also difficult to test exactly as apple to apple. But case Rigol is very extremely clear. Rigol is somewhere out of the way and got lost in the swamp.This old Rigol thread is herehttps://www.eevblog.com/forum/testgear/rigol-ds1074z-weird-signal-level-problem/msg727870/#msg727870But for me, it was noted that these were not good to speak here publicly.

author: markone
author_rank: Frequent Contributor
timestamp: March 18, 2016, 02:30:53 pm
content: Yep, Rigol 1mV vertical scale is utterly fake and 2mV seems too as well.If i turn off persistence on GW the trace gets tinner, with average sampling 2x is getting perfect ;-)I fear that some scopes apply averaging to clean waveforms even if you select "sample" for acquire mode, like seems to happen with my Siglent SDS1102CNL :https://www.eevblog.com/forum/testgear/ads1102cal-%28siglent-sds1102cnl%29-unwanted-signal-filtering/msg880815/#msg880815

author: nctnico
author_rank: Super Contributor
timestamp: March 18, 2016, 11:11:39 pm
content: Quote from: rf-loop on March 18, 2016, 11:25:04 amYou really should learn how to differentiate between marketing BS and practical information. R&S claims a 99.9% probability is good enough to detect a glitch reliablyandandI'll explain: If you take a look at the function with which they calculate probability versus measurement time you can clearly see no amount of time and no amount of waveforms/s gives you 100% certainty there is no glitch in the signal. In other words: their reasoning is fundamentally flawed! If you think 99.9% is good enough you can apply laymen's statistics and say 1 in 1000 products will have a problem. However I prefer to apply Murphy's law: only the prototype will work correctly and the entire production batch will need fixing (probably after the units have been installed around the world and thus need a costly recall)!

author: rf-loop
author_rank: Super Contributor
timestamp: March 19, 2016, 07:03:39 am
content: Quote from: nctnico on March 18, 2016, 11:11:39 pmAmen!Where is GWI wfm/s speed with some different settings? Have you seen this GWI salesmen video where they compare GWI wfm/s speed to "competitors". Fun, is it?Where is GWI segmented memory acquisition speed with different settings? Yes I know there is not trigger rearm delay between segments, it reads in User Manual and of course this is true?They advertise 1mV/div sensitivity without any notice it is only digital side zoomed from 2mV/div.In the paper from Xilinx where they advertise GWI they have get 12x faster wfm/s than GWI previous models. (but there they then perhaps lie because now they talk 120kwfm/s speed and previously they have advertised 50kwfm/s and 80kwfm/s. In Xilinx advertisement they talk they have reached 12 times more wfm/s speed, telling that previously they get 10kwfm/s. Why they talk this if wfm/s is nonsense.In Xinlinx paper they also advertise they now reached also amazing 1mV/div sensitivity added with total junk advertisement sentence.But of course, HP was wrong. Agilent was wrong. Keyshit is wrong. Rohde&Schwarz is now also wrong. Who is next wrong.Please also read (and understand) these materials carefully before you start this your own "salesman argumenting" how in your religion all is right and all others lie.

author: miguelvp
author_rank: Super Contributor
timestamp: March 19, 2016, 07:59:50 am
content: Quote from: nctnico on March 18, 2016, 09:18:37 amWhile I agree that wfm/s is marketing wank, because the number they give you is at certain timebase, memory depth and other factors, it's not totally irrelevant.wfm/s at your current settings will determine how many waveforms the scope can see, the higher the rate the less blind time the scope has therefore allowing the triggering to trigger on events that otherwise would be happening during the scope blind time.But as stated, the wfm/s they give you are probably for a few hundred points and a small time base so the figure they give you has no clear indication of what the update rate is at your current settings.You can hook a frequency counter to the trigger out of your scope and figure out the true wfm/s at your current settings, and then the higher count will mean less blind time and more chances to catch a glitch that otherwise will be missed if the count is very poor.Granted that you could set the trigger options to catch it, but you will have to know the nature of the glitch, but if you don't know it then the higher wfm/s count the better to find it. Maybe using a pass/fail mask instead of staring at the screen

author: Karel
author_rank: Super Contributor
timestamp: March 19, 2016, 08:16:36 am
content: And what if you aren't aware that there is a glitch and you are not actively searching for it?A scope with a high waveform update rate gives you a much higher chance to catch an unexpected error.

author: tautech
author_rank: Super Contributor
timestamp: March 19, 2016, 08:21:52 am
content: Quote from: Karel on March 19, 2016, 08:16:36 amThat's where a fast pass/fail mask comes into it's own, repetitive waveforms of course.

author: miguelvp
author_rank: Super Contributor
timestamp: March 19, 2016, 08:24:16 am
content: Quote from: tautech on March 19, 2016, 08:21:52 amNot if your update rate is poor, the pass/fail mask is only as good as the waveforms the scope can see, so high wfm/s will help regardless.

author: Karel
author_rank: Super Contributor
timestamp: March 19, 2016, 08:35:57 am
content: Quote from: tautech on March 19, 2016, 08:21:52 amWhy should I apply a pass/fail mask if I don't expect anything wrong and I'm not testing for compatibilityor conformity?Is there really an engineer who applied a mask or "wavescan" everytime he hooked up a scope to dosome measurement? Definitely not.In order for a scope with average wfm/sec. to beat a scope with high wfm/sec., you need to activatea mask/wavescan all the time.

author: tautech
author_rank: Super Contributor
timestamp: March 19, 2016, 08:43:08 am
content: Quote from: miguelvp on March 19, 2016, 08:24:16 amExactly, but there's other factors to consider too like DSO computation/processor speed.Examples of this can be seen here in a post by rf-loop:https://www.eevblog.com/forum/testgear/siglent-sds2000-new-v2-firmware/msg830156/#msg830156

author: tautech
author_rank: Super Contributor
timestamp: March 19, 2016, 08:46:27 am
content: Quote from: Karel on March 19, 2016, 08:35:57 amSure, just be careful what you might buy to do this and expect it to work:https://www.eevblog.com/forum/testgear/siglent-sds2000-new-v2-firmware/msg830156/#msg830156

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: March 19, 2016, 10:32:21 am
content: Quote from: Karel on March 19, 2016, 08:35:57 amNo, but not every measurement is there to find a glitch or even a problem, often enough you just need the signal parameters or see how the output changes when input parameters change.But yes, if there's a problem, and I suspect there might be something wrong with the signal then I'll let WaveScan have a run over it.QuoteNo, not really. At least not if you have a somewhat decent understanding of what you're actually probing. And if you don't then you've got worse problems as to wether to enable mask test. That's where being a competent EE comes into play, and no scope can substitute that.Also, mask test only works with static signal parameters (i.e. a repetitive waveform). It does not work with a vast amount of real-life signal, like serial communication, or pretty much any waveform that's non-repetitive. Which makes it utterly useless for an increasing number of test scenarios.

author: wraper
author_rank: Unknown
timestamp: March 19, 2016, 10:52:57 am
content: Quote from: Karel on March 19, 2016, 08:35:57 amWill not help at all, just to automate the process compared to persistence enabled so you don't need to look on the screen. Moreover, mask will drop the waveform update rate even lower (increase blank time), so chances to capture the glitch decrease even more.

author: nctnico
author_rank: Super Contributor
timestamp: March 19, 2016, 11:20:48 am
content: Quote from: Karel on March 19, 2016, 08:16:36 amIn my experience glitches occur randomly and in some cases with long pauses (like 30 minutes or even several hours) in between. Also be aware that waveforms/s is strongly related to memory depth and samplerate so in reality it is very unlikely that you'll have the scope set for the optimal waveforms/s while doing measurements so the chance you spot a glitch accidentally is much smaller.IMHO actively looking for glitches (or better put: unexpected signal abnormalities) should be part of a design testing/verification process.

author: wraper
author_rank: Unknown
timestamp: March 19, 2016, 11:27:42 am
content: Quote from: nctnico on March 19, 2016, 11:20:48 amWhich makes it almost impossible to catch with a low waveform update rate scope.QuoteWhich you don't care about with Keysight scopes as it always is max possible.

author: rf-loop
author_rank: Super Contributor
timestamp: March 19, 2016, 11:33:11 am
content: Quote from: wraper on March 19, 2016, 10:52:57 amNo. It do NOT drop at all wfm update rate if look example Siglent SDS1000X and 2000X models what have hardware based full speed mask test.This is also tested several times. It keep same wfm speed what it have with same settings without mask test enabled.Also I want ask GWI GDS2000E mask test speed but without answer. Only answer was that this feature do not need be fast.

author: nctnico
author_rank: Super Contributor
timestamp: March 19, 2016, 11:35:53 am
content: Quote from: wraper on March 19, 2016, 11:27:42 amThat depends entirely whether the entire memory fits on the screen or not so at some point you'll be looking at part of the memory so the anomaly has a big chance to stay hidden.

author: rf-loop
author_rank: Super Contributor
timestamp: March 19, 2016, 11:41:15 am
content: Quote from: nctnico on March 19, 2016, 11:35:53 amNot case in Siglent *). There is not hidden part of trace outside of display. It was also told very beginning of this thread.Add: SDS1000X and SDS2000X models

author: Performa01
author_rank: Super Contributor
timestamp: March 19, 2016, 11:47:04 am
content: Quote from: Wuerstchenhund on March 19, 2016, 10:32:21 amThat’s certainly basically true, but a mask test can still be helpful in some cases with waveforms that originally are not strictly repetitive – just make them repetitive for the test.I once had to track down a sporadic fault in a serial communication, that had a proprietary protocol for some (good) reasons. Since the fault was sporadic, it was clearly not related to the message content. So I just let the communication partners exchange the very same message repeatedly and set up a mask for the entire message. As expected, the problem was a timing violation, quickly revealed by the mask test.

author: Performa01
author_rank: Super Contributor
timestamp: March 19, 2016, 11:59:06 am
content: Quote from: rf-loop on March 19, 2016, 11:41:15 amYes, the combination of reasonably fast waveform update rate not at all affected by a mask test, deep memory, and never hiding anything from the user, i.e. always displaying the entire acquisition data (which even makes peak-detect dispensable in most cases, except for really slow timebase settings) is a very powerful and quite obviously also rather unique combination in its class.

author: nctnico
author_rank: Super Contributor
timestamp: March 19, 2016, 12:24:41 pm
content: Quote from: rf-loop on March 19, 2016, 11:41:15 amOnly when you let the oscilloscope make the acquisition length shorter/longer depending on the time/div setting. However if you force full memory length at full samplerate then there is no other way than to show part of the memory depending on the time/div setting. This has been explained to you before! Most DSOs (including the Agilent DSO7000 series I have) use a fixed (or maximum) memory length and show part of the memory at full samplerate depending on the time/div setting. IMHO there is not much point in using a DSO which makes the memory extremely short despite it has several Mpts of memory. The whole advantage of a DSO is that it can record a long trace which you can analyse later.

author: rf-loop
author_rank: Super Contributor
timestamp: March 19, 2016, 01:12:26 pm
content: Quote from: nctnico on March 19, 2016, 12:24:41 pmThis is why Sig 1kX have example 14M and 2kX 140M memory. Where is problem? More long memory and (mostly) more slow wfm/s if keep same samplerate. Just how you want use it.

author: nctnico
author_rank: Super Contributor
timestamp: March 19, 2016, 02:19:57 pm
content: You keep raving on about how the Siglent scopes always show all of the signal but that isn't true. It depends on whether you let the oscilloscope select the maximum memory length which fits on the screen or not. If not then there is no other option than to hide part of the signal. Anyway it seem Siglent has fallen into the waveforms/s trap set by the competition and diverted a lot of energy towards having a lot of waveforms/s. What else is a Siglent oscilloscope really good at?

author: markone
author_rank: Frequent Contributor
timestamp: March 19, 2016, 02:40:23 pm
content: Quote from: rf-loop on March 19, 2016, 07:03:39 amCan you show a SDS1202X (20us, 10 Kpts, 50MSa/s) screenshot for 10Khz sine wave with 1mVrms amplitude @ 1mV vertical scale WITHOUT any eres, filtering or other type of signal processing enabled with meas ?Take a look to mine screenshot, the incoming signal, straight from SDG2042X (no attenuator, no 50ohm termination) has of course some noise so it cannot be a single pixel neat line.How can you demonstrate that GW 1mV vertical scale is fake ?Maybe from image pixel analisys ?Keep in account that usually 2000E screendumps are from single pass trace without intensity grading, not so great to see and quite different from what you can see on screen with your eyes,but measurements are stable and reliable.As i already said, this scope line does not shine visually speaking but it's a lot responsive, FFT function rocks, screendump in png format are instant, UIHow can you demonstrate that your scope is not applying anyfiltering trick like mine SDS1102CNLis clearly doing at certain time base settings ?Take a look to the following screens, same signal for both, only time base was changed :It's enough 2x average filter to utterly change the perceived scope vertical resolution :I'm under the impression that with last scope lines Siglent has focused heavily on screen appereance, a good way to attract customer attention but not the main point on scope functions.

author: rf-loop
author_rank: Super Contributor
timestamp: March 19, 2016, 03:31:55 pm
content: Quote from: markone on March 19, 2016, 02:40:23 pmOverlay it with vertical raster what interval is division / 12.5.Do you see any sample middle way of these..But, do same capture with 2mV/div (do not change anything other)Now you can see there is all 25 levels in one division.Do it enough times, run also random noise to it..Also do vertical zoom using stopped scope.After all investigations you may think same..(--- btw, look these same things what are from Rigol DS1000Z. There you find this continue up to 5mV/div.)ADC is 8 bit. There must come out 1 digit variations... where are these hided when use 1mV/div.GWI, as also Siglent use 25 levels vertically for one division.Display is 8 div high. Very easy you can find true vertical height is 10.24 div. 10.24 div x 25 = 256.( Iknow Siglent but I do not know GWI so this was only suspect it have full ADC scale bit over 10 vertical div. )Also other method is you run acquisition and store .CSV to USB stick. Analyze this data.Look true sample data points level distribution.

author: rf-loop
author_rank: Super Contributor
timestamp: March 19, 2016, 04:13:13 pm
content: About your Siglent SDS1102CNL images.They are really really weird. I have sold many of SDS1000CNL/CML models. Tested every single sold individual scope with 24h burn in phase and after then tests before I accept unit pass to end user. I have never seen anything like it, exept if use input DSP filter feature it may give something like this.First time I see (previously) your these images my first suspect is that it is somehow failed. Perhaps some factory hidden cal data corrupted or what ever. Sorry but I feel something is wrong there.Was it same with original ATTEN Firmware? Or did this "feature" come out after you push Siglent FW inside.

author: rf-loop
author_rank: Super Contributor
timestamp: March 19, 2016, 05:17:46 pm
content: Quote from: markone on March 19, 2016, 02:40:23 pmYes after I can go to scope.Btw. I all my previous images here what are about this noise, there is NOT ANY filtering exept if it reads there. Every image where is any level of ERES used there is also iformed it. Exactly. If there is used BW reject, it is clearly noted. If there is any other like average it is noted if used. There is not any other kind of filtering available in SDS1000X.

author: nctnico
author_rank: Super Contributor
timestamp: March 19, 2016, 06:40:09 pm
content: Well... if I recall correctly my SDS2204 automatically forced the 20MHz bandwidth filter on for the 2mV/div setting.

author: tautech
author_rank: Super Contributor
timestamp: March 19, 2016, 07:36:47 pm
content: Quote from: nctnico on March 19, 2016, 06:40:09 pmCorrect, but not so for the SDS1000X series, they have full BW over the whole vertical range, right down to 500uV/div.The new SDS2000X has had further sensitivity improvements to 1 mV/div, I don't have one yet so I can't say if it's BW limited at 1 mV/div and I couldn't find mention in datasheets or Siglent websites.

author: markone
author_rank: Frequent Contributor
timestamp: March 19, 2016, 07:57:16 pm
content: Quote from: rf-loop on March 19, 2016, 04:13:13 pmThe original ATTEN FW was quite a shame, at purchase time i was aware about original Siglent firmware compatibility, so i flashed it few hours after it came out of the box... the scope internals are identical to the SDS1102CNL and similar to Rigol DS1000E scopes ;-)Self calibration was performed several times, dunno if exist something left untouched by this process, anyway if you work with "clean" signals "the feature" is much less evident.Considering the price paid several years ago (around 240 Euro, new) this scope was a good buy.

author: markone
author_rank: Frequent Contributor
timestamp: March 19, 2016, 08:01:52 pm
content: Quote from: nctnico on March 19, 2016, 06:40:09 pmBoth screens were taken with BW limit turned on, anyway the result of the unwanted feature is a lot different.

author: markone
author_rank: Frequent Contributor
timestamp: March 19, 2016, 08:10:36 pm
content: Quote from: tautech on March 19, 2016, 07:36:47 pmBefore to proceed with GWI scope purchase i was considering the SDS2102X, but the complete lack of review / preview on the web prevented me to go ahead.Do you know if something came out in the mean time ?

author: rf-loop
author_rank: Super Contributor
timestamp: March 19, 2016, 09:03:59 pm
content: Quote from: nctnico on March 19, 2016, 06:40:09 pmOhMy SDS2304 do not. Default for 1mV/div and 2mV/div is full BW.I do not know how it is in SDS2000X series but SDS2000 series 1mV/div is derived from 2mV/div using vertical digital zoom.

author: tautech
author_rank: Super Contributor
timestamp: March 19, 2016, 09:19:05 pm
content: Quote from: markone on March 19, 2016, 08:10:36 pmNo I don't,yet. I'd expect their performance to well exceed the SDS2000, the V2 FW was written for both the X series DSO's (SDS1kX and 2kX) and achieved significant performance improvements in the older HW 2000 series of which the 2000X series has evolved from.V2 FW gains included:More available memoryFaster wfm/sImproved Sequence mode1mV/divRemedy of some bugs identified by nctnico and othersPerforma01 went through most of the features and improvements in detail in this thread:https://www.eevblog.com/forum/testgear/siglent-sds2000-new-v2-firmware/

author: tautech
author_rank: Super Contributor
timestamp: March 19, 2016, 09:21:59 pm
content: Quote from: rf-loop on March 19, 2016, 09:03:59 pmYes. V2 FW made this improvement.

author: rf-loop
author_rank: Super Contributor
timestamp: March 19, 2016, 09:27:57 pm
content: Quote from: markone on March 19, 2016, 02:40:23 pmYour scope is named 70MHz and least I do not know at all your real frequency response, specially with 1mV/div bandwidht.But both of our scope have 20MHz BW (but also here true freq response may be different). Then we can be more near apples to apples. Exept, we do not know how much data is really displayed. Many scopes do secondary decimation for display. Primary decimation is other case but this do not matter if do test with same samplerate. (example here 50MSa/s where is propably 1:20 primary decimation from 1GSa/s samplerate. IF it use full samplerate for low speeds what is not nessessary when there is interchip interleaved ADC's. (example, some scope what have 10x 100MSa parallel interleaved separate ADC's for 1GSa may use only one chip for 100MSa and more slow samplerates, least this is possible. This may give also less noise. But, so or so..How ever it works, what we see is result. I can later do full 280MHz BW this 10kHz 1mVrms test and with 20MHz BW and also with 1M input impedance as you have done.

author: nctnico
author_rank: Super Contributor
timestamp: March 19, 2016, 09:57:49 pm
content: Such a test would also require to use attenuators (for example 40dB in total) to eliminate the noise originating from the generator. But still... hasn't the noise been debated to death already? Previous screendumps have already shown the GDS2000E is on par with the SDS1000X. Let's start comparing things like math expressions, protocol decoding, triggering on a protocol, segmented recording, statistics, FFT, saving screendumps, cursor readings, automated measurements, reference traces, data logging and ethernet accessibility & features (like saving files to a network share).

author: rf-loop
author_rank: Super Contributor
timestamp: March 20, 2016, 05:36:09 pm
content: Quote from: markone on March 19, 2016, 02:40:23 pmHere.My quess is also that GWI decimate data for display much more than Siglent because Siglent need as much data as possible for intensidy gradation. (More collissions more brightness. There is two kind of things. Dense data in one shot give collisions when data is crimped horizontally to window. Lot of samples for one pixel. Other thing is waveform upodate speed. How many captures is overlayed due to one TFT refresh cycle. This image include all 14k samples so it also works bit like "peak detect" but bit different way. (from primary decimated data, here from 50MSa/s what is 20:1 decimation from 1GSa/s ADC speed.With gaussian noise, more data give more fat trace.One important thing with noise is bandwidth.HereGWI is from 70MHzscope andSig from 200MHz scope (what have measured 280MHz - 3dB (0dB ref @1MHz)Note different horizontal scale. If you multiply Siglent horizontal(only) dimension to 1200 then scale is around same.Due to BW it is natural that Siglent noise is around 4dB more. Other thing is that perhaps Sig overlay more datapoints to screen it also is meaningful when look visible p-p ("fat trace")Add note: Scope is stopped just because image save system is very different in GWI and Sig. If take on the fly image with Sig, there is lot of traces (depending wfm/s speed) overlayed with full intensity gradation, what you see is what you get to stored image. (not exactly because still eye is slow and brain is handling live image)As told previously, many times, they are not so different if look noise, but raw data to display handling looks very different.But, imho, signal from external source is very questionable way to chaaracterize scope front end noise! It can say nearly nonsense if we do not know signal itself total noise figure exactly.Best way is without any signal. Using 1Mohm and/or 50ohm input if selectable, Specially if use 1M input then inputs need protect carefully from external EMI. (one good method is use metal BNC protection gap or 50ohm termonator so that center pin do not connect - if want keep it still 1Mohm impedance - yes in some cases also this matter)Because we do not know exatly what is going on inside scope HW and software also need be bit careful with measurements if compare different scopes face to face. It depends, as all, many things.One good way is take out real raw sample data and use matlab or example EXEL or OpenOffice calc etc.Data is available from SDS1kX in three form: binarry (.BIN) text for EXEL etc (.CSV) and .DAT for Matlab.I will later show without signal noise with same 14k memory, 1mV/div full bandwidth 50MSa/s (20nss/div)Image + analyzed raw sampledata. (just now have not time to finalize this exercise but data is "in the box")Is it possible to get .CSV from GWI

author: nctnico
author_rank: Super Contributor
timestamp: March 20, 2016, 06:21:38 pm
content: One more then: same 1mVrms signal from 100mVrms signal going into a 40dB attenuator + 50 Ohm terminator to reduce signal generator noise. I measured my GDS2000E to -3dB at 290MHz referenced from 10MHz.I think it is clear the GDS2000E uses vertical zoom to get to 1mV per div. IMHO this is to save some cost in the input attenuator and not due to excessive noise.

author: Performa01
author_rank: Super Contributor
timestamp: March 20, 2016, 10:59:11 pm
content: Quote from: nctnico on March 20, 2016, 06:21:38 pmI agree. Even though I would not say inputattenuatorbut inputamplifier. Additional +6dB amplification at bandwidths ~300MHz might require an extra amplifier - or an automatic bandwidth limit.The Siglent SDS2000 with V1 FW had a genuine 2mV/div vertical sensitivity that was bandwidth limited to 20MHz. With the V2 FW, the 1mV/div have been added and the bandwidth limit was gone. So it was clear, that the original bandwidth limit was a deliberate measure for noise reduction, whereas the input amplifier was indeed capable to provide 2mV sesitivity at full bandwidth (some 350MHz).The 1mV/div had to be implemented in firmware for the SDS2000, to maintain compatibility with the new X-series scopes and their genuine 1mV/div sensitivity.But I can attest that this doesn’t affect noise. If the noise figure is acceptable at 2mV/div, it will not change if zoomed 2x. Visible noise will be twice as much, but the exact same happens when the input amplification is doubled. Noise figure of a scope input cannot be stellar anyway, as the input protection (400Vp in case of the Siglent) will introduce a rather high source resistance, even when the input is shorted externally. This is also why we usually don’t see any significant difference even without internal 50 ohms termination, regardless whether the input is left open or shorted.Only downside of the zoom trick is that the vertical resolution is cut in half. With just 8 bits, we cannot exploit the display resolution anyway, so for 400 pixels height of the trace area we get 200 steps of 2 pixels each. With software zoom it’s 4 pixels then, which isn’t that big a deal, as we hopefully don’t need a sensitivity that high very often.Any software zoom more than 2x will increasingly defeat the purpose and is certainly only acceptable for really cheap low-end instruments.

author: rf-loop
author_rank: Super Contributor
timestamp: March 21, 2016, 06:39:47 am
content: Quote from: Performa01 on March 20, 2016, 10:59:11 pmRoughly, yes.In many scopes what have 8 vertical div there is still bit over 10div for full scale 8 bit ADC data. This is also in Siglent. (other question is amplifier/attenuator V linearity before ADC.)Example in Siglent, there is 50 TFT pixel for one division. 8 div is 400pix and full ADC range is 512 pixel, 10.24 div. Mostly 1 ADC step is 2 pixel and one div is divided to 25 steps. (when zoomed 2x this one division is divided to 12.5 steps (4pixel)For normal use, together with noise this digital 2x zoom is, not very good, but acceptable. Of couse it do not add average noise and mostly ADC itself is noisy and analog front end is noisy. Even if system is too free from noise in some cases we need add noise for add averaged result improvement. In these kind of equipment do not need add noise, they have enough.About 50ohm/1Mohm. In this kind of scopes we do not find real 50ohm impedance front ends at all. Front end is still 1Mohm. Only there is cheap 50ohm resistor connected parallel with input termoinal. After then it continue to this 1Mohm pathway. If we do true well RF designed 50ohm from input connector to ADC input we can design much less noisy front end.In some cases this "el cheapo" construction these "50ohm" inputs are 50ohm only for DC. I have tested some scope what have 50ohm and 1Mohm selection. With its own internal "50ohm" result may be less good than using 1Mohm selection together with external (high quality) feed thru termination but what is also bad solution.But, we get what we pay.Also, it is true that need of 500uV - 2mV/div sensitivity is not very often needed in average everyday use. Mostly if we work with low signal levels we have very different tools than cheapest scope alone. Some may tell that some his audio work he want look low level signals. Yes, perhaps. Then I ask why you use wide bandwidth RF oscilloscope for this work. Of course it is more or less too noisy. Use 100kHz BW scope and result is (much) better.

author: rf-loop
author_rank: Super Contributor
timestamp: March 21, 2016, 07:23:48 am
content: Quote from: rf-loop on March 20, 2016, 05:36:09 pmHere it is.Scope stopped so that image and saved raw ADC data is same. saved using .CSVWhole data "analyzed" using OpenOffice calc.This method how I did it is not for scientific perfection.As can see there is also counted every level so we can see distribution. As can see last peak peak include also rare peaks. This is why more data give more desity to peak and trace visual fatness grow.Also there is raw .CSV just as it come from scope. (btw, SDS1kX saving to USB is amazing fast if compare some older Siglent.)For this .CSV remove extra file extension .TXT. It is there only because forum do not accept this .CSV (really, why)Also, this image + raw adc data give more evidence that there is nor secondary decimation for image. Or least it is not so much.One evidence is if you take image handling and you count these most or second most high peaks in positive and negative side.There is no loss! (exept in case that there is two or more peak values so that they are inside one pixel on TFT horrizontal axis.)Most easy is calculate bottom 3 peaks and top 9 peaks (distribution table). No one is missing. Propability that all is there if there is high amount decimation is... this do not proof but give small evidence... I have looked many images and also looked how they may be mapped to TFT so I have qquite strong believe, they do not decimate least in this case where trace lenght is 700 pixel and data lenght is 14000 points. But of course after there is more density data point go to same pixel in TFT map what also other data point. This give intensity garadation also for slow speeds where may be even only only one acquistion for one TFT cycle.

author: timb
author_rank: Super Contributor
timestamp: March 21, 2016, 08:25:13 am
content: I was curious how low of a signal I could trigger on with my old analog scopes:1mV P-P 10MHz Sinewave w/ 50% Random Noise on a Tek 2465B500uV P-P 10MHz Sinewave w/ 50% Random Noise on a Tek 22251mV P-P 250MHz Sinewave on a Tek 2465BNone of these would trigger my digital Tek MSO2020B. (Well, the 10MHz 1mV signal may have worked if I triggered from the function generator's trigger output.)

author: rf-loop
author_rank: Super Contributor
timestamp: March 21, 2016, 09:30:13 am
content: Yes, analog scopes show "nice" image as this my old Tek 2445B (I'm lazy and do not take more old Tek's and HP's to on the table. In cold store it was just first one near the door.Of course trigged from main signal, not ext.This is slow signal. But reason was previously to someone's other image for apples to apples.Analog scopes are also noisy, but phosphor is good noise filter. Yes I can turn average on and it is nearly same.. (for continuous repeating signal. It filters noise away nearly like phosphor. Most phosphors drawing speed is very slow and digital is free from this effect.Also there is tubes for faster draw speed but still they are slow as hell if compare digital. THis do not at all mean that analog scope is bad. It is not bad, in many applications. They are just exactly as good as they have been in 60, 70, 80, 90 etc.. and with these we have done small "miracles" but it need also more skills than many think (if do some miracles).One look modern SMPS wide BW noise with his analog scope and tell that it is very very good, very low noise (ripple).Then I tell him that no, it is so crap that it is like jammer transmitter. He believe more his analog than my digital...oh digital scopes itself are so noisy... I tell him... stop before you start. Do you think also my spectrum analyzer is so noisy... how many kilometers you want we go to listen your SMPS working nice cheap "laboratory" power supply, we can connect it here to antenna and take its "noise signature" and then we can go out with my spectrum or mesurement receiver.Yes he have later purchased digital scope.... and today his analog is still in his work room, for curiositu, for nostalgy and for decorating...But so or so, I still use also some of my analog for my works, with it I earn more salary that with digital (in some cases)What analog I mostly have used. Not 2465, not 2445, not some 7000 work horses. ok, 2235 (Mil version) and 2446A. Perhaps one reason is speed of use and never aliasing. UI is super fast and no need to search any menu and push this and scroll this and push agen and carefully scroll here and there...for select settings no.Connect scope to test point turn analog scope knob(s) what muscle memory know with closed eyes and signal is there, visible without hassle and with near zero time. Look waveform figure is "bad". Turn this pot (or inductance adj) and work done, Rb get lock agen and agen part of rumors about of Rb lamp short lifetimes is flushed out from toilet. Time is money.

author: Performa01
author_rank: Super Contributor
timestamp: March 21, 2016, 11:54:18 am
content: Quote from: timb on March 21, 2016, 08:25:13 amOkay, challenge accepted.Let’s just recall what the benchmark is:Tek 2465B offers 2mV/div @ 350MHz bandwidth.Tek 2225 bandwidth is limited to some 5MHz at 500µV/div (at x10 vertical magnification).Here’s some similar test scenarios with a Siglent SDS2304X, 1mV/div @ 350MHz bandwidth.500µVpp 10MHz Sinewave + 50% noise, 350MHz bandwidth:500µVpp 10MHz Sinewave + 50% noise, 20MHz bandwidth (to be a bit closer to the Tek 2225):1mVpp 250MHz Sinewave:1mVpp 400MHz Sinewave (exceeding the scope bandwidth, thus introducing some 6dB attenuation, so it’s more like a 500µVpp test):Note that the frequency counter as well as automatic frequency/period measurements display mostly rubbish at such low signal levels; automatic measurements also show higher pk-pk value due to noise.

author: nctnico
author_rank: Super Contributor
timestamp: March 21, 2016, 02:46:12 pm
content: If the frequency counter shows something different than the frequency of the signal it is supposed to trigger on then the trigger isn't stable / triggering properly!

author: timb
author_rank: Super Contributor
timestamp: March 21, 2016, 03:51:59 pm
content: Quote from: nctnico on March 21, 2016, 02:46:12 pmNot always true. There's a frequency counter option for the Tek 2465 series (CTT - Counter Trigger Timer) that adds a high resolution counter which is completely separate from the trigger based counter. The CTT counter only goes up to 200MHz whereas the trigger counter will report up to the scope's full 400MHz bandwidth.Aside from that, I've run into situations on both modern DSOs and vintage CROs where I can get a stable waveform by tweaking the trigger level jussst right, because the signal is too small, fast or noisy for the auto-trigger circuitry to work with. If the auto-trigger can't pick up the signal than it can't report the frequency.

author: nctnico
author_rank: Super Contributor
timestamp: March 21, 2016, 04:29:05 pm
content: AFAIK auto trigger is just a time-out to get a trace on the screen without signal if there is nothing to trigger on. It is not some kind of automatically adaptive triggering system.

author: rf-loop
author_rank: Super Contributor
timestamp: March 21, 2016, 04:47:14 pm
content: Quote from: nctnico on March 21, 2016, 04:29:05 pmIt depends...But yes, if we talk modern digital side trigger system scopes, also AFAIK, it is time. If trigger is missing after scope is ready for next waveform trig then "auto" produce trig. Depending scope, sooner or later and also how user have set hold on time lenght or holdoff off.This is fun case, we can see guite stabile triggered signal on the screen but still example half of cycles do not produce trigger pulse for counter. But still enough triggers that auto do not trig and when get trig it is from right position in cycle rising edge and waveform is well positioned and still scope may reach full or near full waveform update speed. (many times in these cases there is so much noise related to signal that it may have some trig jitter.) If user is without enough experience and/or knowledge he may drop to also this trap, specially if there is only 1% or 0.1% missing trig pulses for counter and very stable continuous waveform display on the screen.There ia also some differencies if look convetional or low end digital scopes where is analog trigger circuit pathway instead of modern full digital side trigger engine after ADC.(sidenote for previous msg by @timb, Yes Tek CTT is nice. I have some scopes where is also this)

author: markone
author_rank: Frequent Contributor
timestamp: March 21, 2016, 08:49:39 pm
content: Just to confirm that GWI 2000E 1mV vertical scale is fake, here are my screenshot and .csv file for 1mVrms from 40dB attenuator, 50ohm external input termination.The finest voltage step inside capture data file is 80uv, that is compatible to 2mV vertical scale (0.002 x 10 / 250 = 80uv).PS : .png and .csv files are from different sweeps

author: rf-loop
author_rank: Super Contributor
timestamp: March 22, 2016, 04:32:45 am
content: Quote from: markone on March 21, 2016, 08:49:39 pmIf compare to your previous images need note that samplerate is divided by 10, perhaps accidentally?(about "fake" V/div. Look Keyshit InfiniiVision 2000 X series. What is also known about high noise.There is also 1mV/div. But, there is 1mV/div and 2mV/div, and both only fake, vertical zoomed from 4mV/div.

author: tautech
author_rank: Super Contributor
timestamp: March 22, 2016, 08:53:46 am
content: Quote from: Performa01 on March 21, 2016, 11:54:18 amAh ha, so you have a X series now, how do you like it compared to the SDS2304 you previously had....or do you have 2 x 300 MHz 4 channel Siglents now?

author: nctnico
author_rank: Super Contributor
timestamp: March 22, 2016, 10:04:48 am
content: Quote from: markone on March 21, 2016, 08:49:39 pmStill the noise level is very low so even though the 1mV/div is zoomed from 2mV/div it is actually useful.

author: markone
author_rank: Frequent Contributor
timestamp: March 22, 2016, 01:20:44 pm
content: Quote from: rf-loop on March 22, 2016, 04:32:45 amI purposely lowered the number of acquired pts to 1K to reduce the distance from what we see on screen and what we have in .csv file.

author: markone
author_rank: Frequent Contributor
timestamp: March 22, 2016, 01:28:48 pm
content: Quote from: nctnico on March 22, 2016, 10:04:48 amI agree,and if you use averaging sample mode you obtain a very neat sine waveform even at low counts (average 2 or 4).Have you tried FW 2.4 ?

author: rf-loop
author_rank: Super Contributor
timestamp: March 22, 2016, 02:26:18 pm
content: Quote from: markone on March 22, 2016, 01:20:44 pmSorry but now I do not understand what you mean.a If you have 10k memory, 20ns/div tb and 50Msa. Acquistion lenght is exactly 10 division what is width of display.b If you have 1k memory, 20ns/div tb and 5MSa/s. Acquisition lenght is exactly 10 division agen.But, with a you have much less data. You know what less data mean when we talk about something like gaussian distributed random noise.What least I do not know is that do GWI map all samples in both cases to display or do it secondary decimation for display.

author: nctnico
author_rank: Super Contributor
timestamp: March 22, 2016, 02:36:45 pm
content: Quote from: rf-loop on March 22, 2016, 02:26:18 pmThe line would be 1 pixel in height if it would do decimation (averaging) but since the noise grows with the number of samples compacted into 1 vertical display line the conclusion is that GWI to does intensity grading based on how many samples hit a certain spot. GWI isn't throwing away or filtering any samples!

author: markone
author_rank: Frequent Contributor
timestamp: March 22, 2016, 02:54:39 pm
content: Exactly because we do not know the display decimation algo lowering data samples segment results in a more understandable analysis about what you see and what you get.In addition last FW upgrade, that i have just flashed, seems to have modified the display waveform representation.Anyway this capture data set was simply intended for a rough 1mV vertical scale sampling resolution analysis, not statistical study of noise floor as you did.

author: rf-loop
author_rank: Super Contributor
timestamp: March 22, 2016, 04:50:41 pm
content: Quote from: markone on March 22, 2016, 02:54:39 pmYes, ok. I just only like understand what I see for better understand how these equipments do things.My thin suspect is that GWI is mapping less data to display than Siglent. Siglent need map as much data points to display as possible/available, for intensity gradation what works also with very low wfm/s speeds, even if only one wfm for one display update cycle..Imho, with these scopes, SDS1kX and SDS2k(X) and GDS2kE no need worry noise. They are very good in this price group. I think it is clear. I like to say, if look front end noise alone, these belongs to group where are best what can buy in this class of scopes. Both.

author: nctnico
author_rank: Super Contributor
timestamp: March 22, 2016, 04:55:05 pm
content: Quote from: rf-loop on March 22, 2016, 04:50:41 pmWhy would that happen?

author: pxl
author_rank: Regular Contributor
timestamp: March 22, 2016, 08:14:28 pm
content: Quote from: nctnico on March 22, 2016, 02:36:45 pmWhy would the scope do any averaging between any (otherwise unused) samples? In this case the noise would be averaged as well, which would falsify the waveform. Averaging is ok, if it is intended to do, but doing it without direct intention would be a bit surprising, wouldn't be?I would expect to drop any unused samples (except peak detect mode).

author: markone
author_rank: Frequent Contributor
timestamp: March 22, 2016, 08:36:26 pm
content: Quote from: pxl on March 22, 2016, 08:14:28 pmThis is the best way to show horrendous waveforms on the screen with complex signals, ie a sine wave loaded with high order and high amplitude harmonics.Even if you do not want peak detection you cannot simply drop unused sample, some kind of complex downsample algo must be applied to fill scope's screen with decent curves.I learned that years ago when i was coding on a FPGA based system that was sampling high power current & voltage signals @ 1MSa/s, representing them on 10ms wide waveform graphs with a simple lossy decimation process is not adeguate at all.

author: nctnico
author_rank: Super Contributor
timestamp: March 22, 2016, 09:55:09 pm
content: Quote from: pxl on March 22, 2016, 08:14:28 pmBut it doesn't. At a length of 10kpts there are 1000 samples per division if there are 10 horizontal divisions. If the graticule has a width of 750 pixels then each division is 75 vertical lines wide. Those 1000 samples will be fitted into 75 vertical lines so for each line the values of 13.3 samples are used. Those 13.3 samples are then used for creating an intensity graded line. If one value occurs more often that position in the line will become brighter. Again: no information is discarded. This process is clearly visible in the various screenshots!

author: pxl
author_rank: Regular Contributor
timestamp: March 22, 2016, 10:09:57 pm
content: Quote from: markone on March 22, 2016, 08:36:26 pmWell, I would expect exactly like that. If there is not enough sample and the curve is ugly, that is very important information, worth not to lose.Quote from: markone on March 22, 2016, 08:36:26 pmDoes anyone have references for this kind of algorithm? (It is not intensity gradient, that transforms several different values to several pixels / several similar values to a pixel via a histogram. But converting several different values to one pixel?Quote from: markone on March 22, 2016, 08:36:26 pm1MSa*10ms = 10000 pixel/screen, that means (calculating with 600px wide screen) 1666 samples to one line of vertical pixels. That seems pretty much data for a nice gradient display. Probably it was a tradeoff in the intensity gradient algorithm (being pretty vs fast).

author: pxl
author_rank: Regular Contributor
timestamp: March 22, 2016, 10:16:00 pm
content: Quote from: nctnico on March 22, 2016, 09:55:09 pmOkay, the method you described is processing the memory data to display data, isn't it? This works from samples from memory and translates several different values to a line of pixels with different gradients. That's ok, but now we are dealing with samples what we do not want to process, because we do not have resources for. Should we have enough power to do that, we could copy to memory as well (assuming we have the sufficient memory).Probably you are right, I am just curious, how could it work?

author: pxl
author_rank: Regular Contributor
timestamp: March 22, 2016, 10:35:22 pm
content: Quote from: pxl on March 22, 2016, 10:09:57 pmThinking it again, it makes sense to presume on slower timebases, that even with such amount of data is not enough to draw an accurate representation of the waveform, so it should fill all the values (between min and max values) with a single gradient, because that is better than trying to guess the real distribution of values and showing a totally fake waveform (it would be an intensity gradient version of an aliased waveform). Just thinking.

author: markone
author_rank: Frequent Contributor
timestamp: March 23, 2016, 12:42:28 am
content: Quote from: pxl on March 22, 2016, 10:09:57 pmNo intensity gradient luxury for that power control applicationIt was a simple single pass averaging hi-res mode implemented inside the FPGA, it's fast and requires small amount of memory, of course it has a low pass effect and hides short glitches but at least you do not see aliasing artifacts.The resulting data stream was used only for waveforms representation, while the control loop was using full data sampling.It's similar to low pass and downsample, but depending on the platform hi-res could be simplier to be coded.

author: pxl
author_rank: Regular Contributor
timestamp: May 04, 2016, 09:22:43 am
content: Quote from: rf-loop on March 10, 2016, 09:41:53 amHmm, there is something I really don't understand here. If this ERES, it should enhance the quantization (resolution), so it should display values between the standard 256 level/8 bit. Still it does not do that. Why?

author: rf-loop
author_rank: Super Contributor
timestamp: May 04, 2016, 02:13:37 pm
content: Quote from: pxl on May 04, 2016, 09:22:43 amBecause, least at this time with available FW versions, ERES implementation is poo.... or is it more polite to say, not best implementation what need some developing.

author: pxl
author_rank: Regular Contributor
timestamp: May 04, 2016, 03:02:12 pm
content: Quote from: rf-loop on May 04, 2016, 02:13:37 pmAhh... Please give them my warmest regards. They just lost a costumer.(I will think that twice, but... c'mon!)

author: rf-loop
author_rank: Super Contributor
timestamp: May 04, 2016, 04:26:03 pm
content: Quote from: pxl on May 04, 2016, 03:02:12 pmIt can not say that it do not work (previously situation was - It did not work). It works. But, you can not get out enchanged resolution - after processing data is still 8 bit as far as I know.But nowDisclaimer: I do not know how it is in SDS2000X (!)I know only how it is in older SDS2000 and how it is in SDS1000X what naturally have lot of less brute force for processing data.

author: pxl
author_rank: Regular Contributor
timestamp: May 04, 2016, 08:22:31 pm
content: Quote from: rf-loop on May 04, 2016, 04:26:03 pmI am afraid it means it does not work. Enhance by n bits means it enhances the resolution by n bits. And because it is specified:"Eres Enhance bits: 0.5, 1, 1.5, 2, 2.5, 3 Selectable"it means that this is a critical bug, which should be fixed asap, as the device does not fit to specs at this point. False marketing, you know... That is a totally different question, that the ERES does filtering as a side effect, which is often used, indeed. But this is a just a side effect, which reduces the usefulness of the ERES, so there are techniques to reduce that.I hope that they will fix this soon.

author: rf-loop
author_rank: Super Contributor
timestamp: May 05, 2016, 08:19:50 am
content: Quote from: pxl on May 04, 2016, 08:22:31 pmERES is many times misunderstooded more or less. (I do not mean at all you!)Peooples who are interest what is ERES, It is good to look first WHAT is ERES and what it do and very importantly - what is is not - what it do not. These last two ones are very important.After then also think if in some system it is implemented better and in some system bit limited. (like example in Siglent 1kX, 2k and 2kX there is acquisition lenght limit. I do not know how it is in Siglent-LeCroy 3000)LeCroy Enhanced Resolution ERES, App note 006aAV 006a:QuotePosition 1. In SDS1kX and SDS2k it is not as LeCroy AN explain. (2kX I do not know)Position 2. This looks like working and also measured 0.5 - 3.0 settings bandwidth and it also match with LeCroy AN