Down and dirty beginners oscilloscope? - Page 1
Forum section: electronics / testgear

author: asisensei
author_rank: Newbie
timestamp: January 21, 2016, 07:58:15 am
content: Hi all,I know it's been talked up and down on the forums, I know, I've searched and read for it seems like days. What I really want to know is what is a good, inexpensive oscilloscope for the total beginner to get? I'm looking at reliability, the manufacturer providing timely updates to the firm and software, quality and standing behind the equipment. Looking at the available scopes, which ones have the least bugs? Many of the conversations on the board are older, so how has the equipment matured and are the bugs finally worked out now? I know things like the Rigol 1052 has been a workhorse, but is it worth it to get one and hack it or is it better to get something like a Siglent sds1072cml which by the specs, is much better that the Rigol? Thanks for listening.

author: ataradov
author_rank: Super Contributor
timestamp: January 21, 2016, 08:22:11 am
content: Rigol DS1054Z.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: January 21, 2016, 09:14:05 am
content: Quote from: asisensei on January 21, 2016, 07:58:15 amThat depends ona) what you want to doandb) your budgetQuoteBoth Rigol DS1052 and Siglent SDS1072CML are bottom-of-the-barrel scopes and were great choices a couple of years ago, but both have been replaced by more capable successors since then.Rigol has the DS1000z Series of low-cost 4ch scopes where the lowest bandwidth model (DS1054z) is shockingly cheap, plus it can easily be hacked to provide >100MHz bandwith. The hardware is at a decent quality level (especially considering its low price) and the firmware is somewhat mature (many of the initial bugs have been fixed by now). At the moment there is probably no better bang for the buck than the DS1054z.Siglent has recently come out with the SDS1000X Series which is a replacement for the old SDS1000CxL. As their predecessors the SDS1000X are 2ch scopes, plus they are pretty new so there's little experience as to bugs and issues. Plus the prices are close to what Rigol asks for it's 4ch DS1054z so it's really a no-brainer.QuoteYeah, I'd like to get that, tooThe simple fact is that you get what you pay for, and despite the cheap Chinese kit real quality equipment and proper support still costs some serious money.Rigol and Siglent both offer only basic support, and pretty much any of its gear comes to market with at least several bugs which may or may not get fixed at some point later on. Rigol can be quite good at fixing bugs, but seems to do so only for the products that really sell in high numbers like the DS1000z or the DS2000 scopes. Others (like the DS6000) have still major bugs even after more than half a decade on the market, and it's unlikely that these bugs will ever get fixed. Siglent has shown to be more inept in fixing software, and while they eventually fixed some of the major bugs of its old SDS1000Cx scopes they seem to struggle to do the same for their newer, more complex scopes. The SDS2000 (not really a bottom-of-the-barrel scope) still suffers from major firmware problems even after two years on the market, and often updates even introduce new problems.On the other hand, Rigol and Siglent kit is cheaper (often a lot) than similar big brand kit. You just have to be aware that there's no such thing as free lunch, and the lack of support and maturity is part of the reason why the Chinese B-brands can be so cheap.I myself had various Siglent and Rigol products, plus there are a number of devices from both manufacturers in my direct environment. However, at the end I found I could not live with the various quirks and issues, and went back to 2nd hand big brand gear which is regularly more mature, more reliable and (despite being used) often still much better supported than new B-brand kit.Having said that, for a beginner the Rigol DS1054z is a great scope, and the remaining bugs shouldn't present any major obstacles for someone who does his first step in electronics. It's really an incredible good value for money, and should serve well until you have outgrown it, at which point I'd then start looking at the big brands.

author: rf-loop
author_rank: Super Contributor
timestamp: January 21, 2016, 01:53:59 pm
content: Quote from: Wuerstchenhund on January 21, 2016, 09:14:05 amI have owned both.After short use for one work what need _cheap_ 4 channel oscilloscope I made conclusion that I do not want anymore use this DS1000Z for any purpose.Also it was case where do not daily adjust scope for different tests. Sorry but I do like these shared vertical adjustments for all channels.SDS1000X have some advantages over DS1000Z.-Bigger display (8" vs 7")-separate vertical adjustments-internal 50 ohm input impedance or is is better say resistance. Rigol --lot of less signal noise-always switchable Sinc on/off (and also not this Sinc joke what Rigol have. Explanation in other thread)-always bacround running history, up to 80000 previous waveforms. Rigol --max 60000wfm/s in normal mode. Rigol much less-256 level intensity grading and far better than in DS1000Z-color grading, Rigol --max 60000wfm/s mask test and speed independent of result, Rigol much slower and also speed depends result what leaads to extremely low speed-max 500000 segment/s speed in Sequence mode with timestamps. Rigol - (or some kind of slow frame recorder)-true analog 500uV/div full bandwidht sensitivity. Rigol - (Rigol 1mV/div is pixel zoomed fake sensitivity and perhaps also 2mV/div in is not true analog sensitivity.)-much better trigger accuracy (perhaps least partially due to Rigol noisy input?)-when I owned Rigol I also used it small time to common purposes "looking around" and there was lot of situations where scope crash and only solution was shut off and start agen what also was frustrating due to long boot time.About Rigol Sinc and vertical sensitivityexamples about Rigol noise. All as perfect face to face and both just fresh selfcal.It need also note that this is 200MHz model. 100MHz model have aaround 3dB less noise (due to bandwidth) and this is also confifrmed by tests).No need comment.Then if just look Siglent SDS1000X and Owon XDS3000A(but here need also note that Owon is 100MHz model and Siglent is 200MHz model)Single shots.Not bad.In this case my opinion is that Owon beats Siglent clearly (also Zoom is better because Owon have vertically higher zoom window. And Owon have full vertical range display where Rigol and Siglent only 80% from full scale) And lot of better TFT what Rigol or Siglent. Better contrast and brightness and wiev angle.

author: tggzzz
author_rank: Super Contributor
timestamp: January 21, 2016, 02:35:57 pm
content: Quote from: asisensei on January 21, 2016, 07:58:15 amIn that case you will know that the answer depends on your budget and what you want to use it for.

author: pascal_sweden
author_rank: Super Contributor
timestamp: January 21, 2016, 03:29:52 pm
content: Is it really true that the Owon has a much lower noise level?From the pictures above it makes me conclude that the Owon has the lowest noise level, then comes the Siglent, and finally comes the Rigol.Is it really true that the Rigol has the worst noise level of all of them?Is this both on the DS1000Z series and the DS2000A series?Which Owon and Siglent models were used for these noise level measurements?Just to double check that we are comparing apples with apples

author: rf-loop
author_rank: Super Contributor
timestamp: January 21, 2016, 05:15:06 pm
content: Quote from: pascal_sweden on January 21, 2016, 03:29:52 pmWith Owon and Siglent. This was NOT noise level compare test. It was only overall look to some things face to face. But it also show something about noise.Siglent model in images:SDS1202X (200MHz)(if substract around 3dB from Siglent noise then it is somehow comparable with these named Owon and Rigol)Owon model in images:XDS3102A (100MHz)(note: in image it is selected to run in 8bit ADC mode just for more near apples to apples)Rigol model in images:DS1074Z (@100MHz)If look front end noise Rigol drops clearly to its own class below both of these more expensive scopes. All can understand that 4 channel scope with Rigol price there must be also other things than el cheapo solutions (example in front end) perhaps just goverment subvention money for get more export. We all know that Rigol is "Beijing" company".

author: ataradov
author_rank: Super Contributor
timestamp: January 21, 2016, 05:43:33 pm
content: If you are a beginner, I don't see how this level of nose is going to be a limiting factor. For general use it is perfectly acceptable, and 4 channels is a really good thing to have, so I would not even look at anything with 2 channels for a first/singe scope.

author: Karel
author_rank: Super Contributor
timestamp: January 21, 2016, 05:55:27 pm
content: Don't buy anything from Siglent if you are not sure you don't want to sell it on Ebay later...

author: tautech
author_rank: Super Contributor
timestamp: January 21, 2016, 06:21:13 pm
content: Quote from: ataradov on January 21, 2016, 05:43:33 pmMaybeHave you seen this thread?https://www.eevblog.com/forum/testgear/ds1054z-noisy-front-end/

author: tautech
author_rank: Super Contributor
timestamp: January 21, 2016, 06:22:59 pm
content: Quote from: Karel on January 21, 2016, 05:55:27 pmYou overlook that Rigol was involved in similar behaviour, so don't buy either?

author: ataradov
author_rank: Super Contributor
timestamp: January 21, 2016, 07:11:14 pm
content: Quote from: tautech on January 21, 2016, 06:21:13 pmYes, I have. What are you looking for at 1 mV/div scale? I'm not saying that it is not a problem for any application, but most hobby uses will never go this far. When you work at those levels, your hardware has to be designed accordingly, and at that point you should not have questions on what scope to pick.

author: ataradov
author_rank: Super Contributor
timestamp: January 21, 2016, 07:21:48 pm
content: And just for some perspective. Here is a picture of a Tek TDS2024B with input terminated. It does not go below 20 mV/div and at that setting it automatically limits the the bandwidth to 20 MHz.That Tek is still sold for $1000-2000.

author: tautech
author_rank: Super Contributor
timestamp: January 21, 2016, 07:28:14 pm
content: Quote from: ataradov on January 21, 2016, 07:11:14 pmPSU ripple would be the most common use.QuoteRubbishDefine hobbyist.Someone with no qualifications yet is involved in design and build?Hundreds of EEVblog members would match this criteria.One needs to know what one measures is reasonably accurate and at low levels any noise is reason to question what you see. While there are ways to tune noise from signals of interest, the lower the starting point the better.Quote from: ataradov on January 21, 2016, 07:21:48 pmIt does if the input is set to a 1:1 probe.BTWI've got a 2012BEditTypo

author: tautech
author_rank: Super Contributor
timestamp: January 21, 2016, 07:40:08 pm
content: Quote from: ataradov on January 21, 2016, 07:21:48 pmHow can this be a comparison?A 20 + yr old design against recent design....you'd expect a modern design to whip the Tek andsomedo.

author: Muxr
author_rank: Super Contributor
timestamp: January 21, 2016, 07:48:03 pm
content: Quote from: Karel on January 21, 2016, 05:55:27 pmWhy is that?

author: ataradov
author_rank: Super Contributor
timestamp: January 21, 2016, 07:50:49 pm
content: Quote from: Muxr on January 21, 2016, 07:48:03 pmhttps://www.eevblog.com/forum/testgear/siglent-they-filed-a-'wrongful-trademark-claim'/And yes, Rigol did similar things, but not anymore. The jury is still out on Siglent.

author: asisensei
author_rank: Newbie
timestamp: January 21, 2016, 08:00:27 pm
content: Thanks everyone for the responses. My budget is fairly low and I'm just getting into this as a hobby to work of vintage stereo's. I don't have any training, I'm reading the Navy manual to learn the basics. I know people talk about the Rigol DS1054Z, I see the bug thread and wonder. Wouldn't the older, more mature inexpensive scopes work? Although I'd like to live in shiny new thing land, I'm full time in grad school now and am using this to help get my mind off the stress.

author: Muxr
author_rank: Super Contributor
timestamp: January 21, 2016, 08:05:19 pm
content: Quote from: ataradov on January 21, 2016, 07:50:49 pmThanks! That's kind of messed up.

author: Muxr
author_rank: Super Contributor
timestamp: January 21, 2016, 08:34:53 pm
content: Could the noise difference be explained with the sample memory setting or bandwidth limiting, although based on those screenshots it looks like that's not the issue?Dave got a quite a bit of noise out of the Tek MDO scope, which are pretty beastly scopes:https://youtu.be/Znwp0pK8Tzk?t=669

author: ataradov
author_rank: Super Contributor
timestamp: January 21, 2016, 09:17:28 pm
content: Quote from: asisensei on January 21, 2016, 08:00:27 pmNo. All low cost scopes have bugs. With more popular models, you see more people trying and you get more feedback. But in reality, you are not very likely to hit most of those bugs."Mature" with low cost scopes mostly means "abandoned". Manufacturers have no money to improve software on multiple models at the same time.

author: tggzzz
author_rank: Super Contributor
timestamp: January 21, 2016, 10:46:43 pm
content: Quote from: asisensei on January 21, 2016, 08:00:27 pmFor those purposes virtually any scope will be sufficient. If money is tight then I would go for virtually any old analogue scope, preferably one that has a 1mV/div setting.Then, as and when you have more money and different objectives, you will be in a better position to know what you need.Not worrying about high bandwidth (10MHz is more than sufficient) will enable you to use scopes that other people are simply throwing out. Certainly my local hackspace has more scopes like that than we know what to do with; some are marked "for disposal" and it won't be worth us trying to sell them.So have a look in local adverts, on ebay, and at local hackspaces or maker spaces. Don't pay more than $20, unless it is for a working Tektronix

author: tautech
author_rank: Super Contributor
timestamp: January 21, 2016, 11:05:44 pm
content: Quote from: asisensei on January 21, 2016, 08:00:27 pmOf course they will and well for most that you will need to start with. Don't be too tempted by old CRO's, while some are still very nice, should it bust could you fix it?Of the models I have sold the SDS1102CML has been the most popular. Sold to hobbyists and repair technicians and feedback has been very positive as it is a mature product. You won't sacrifice much BW selecting a 1072CML and if you want to save a little more the SDS1***CNL series is just as reliable but with less memory. I have 15 units of SDS1102CNL in a military training school for a couple of years with no problems.http://www.siglentamerica.com/pdxx.aspx?id=50&T=2&tid=1When I selected a brand to represent, one of the criteria was 400V channel inputs of which Siglent has maintained on all models and IMO is another feature overlooked by amateurs when selecting a scope.Why?Mainly for repair of mains powered SMPS were the primary side is often ~325 VDC and above the max channel input rating of many scopes, not that this might matter too much for those experienced, but newies make mistakes and blown inputs in scopes I sell is something I can do without.EditAdd link

author: Fungus
author_rank: Super Contributor
timestamp: January 22, 2016, 12:29:07 am
content: Quote from: blueskull on January 21, 2016, 11:37:06 pmWhere can I get one for $99?

author: Fungus
author_rank: Super Contributor
timestamp: January 22, 2016, 12:33:39 am
content: Quote from: rf-loop on January 21, 2016, 01:53:59 pmIf it can pick up 1mV of noise at 20ns/div then it should be commended.If your 'scopedoesn'thave that noise then it's because it doesn't have enough bandwidth. That'sworse.

author: ebastler
author_rank: Super Contributor
timestamp: January 22, 2016, 11:23:18 am
content: Quote from: Fungus on January 22, 2016, 12:33:39 amI'm not sure I can follow that argument. If the noise is actually present on the incoming signal, then it makes sense. But I understand that rf-loop's assumption is that the incoming signal has negligible noise, and the noise we see is generated by the scope's input stage.Nevertheless, I would caution against a noise comparison based on how the traces look on the screen. This will be influenced by the intensity grading and persistence settings of the scope, and the default values used by different brands may well differ. An RMS noise figure determined by the scope from all incoming samples (hopefully...) is more meaningful in my view.

author: MT
author_rank: Super Contributor
timestamp: January 22, 2016, 07:02:42 pm
content: Quote from: blueskull on January 21, 2016, 11:37:06 pmAre you talking about Digilent Analog Discovery 2? Where can one find such for 99usd?Edit:Ah it's student price!

author: Fungus
author_rank: Super Contributor
timestamp: January 22, 2016, 08:16:40 pm
content: Quote from: ebastler on January 22, 2016, 11:23:18 amDid rf-loop have a BNC terminator on the input when that screenshot was taken?I'm thinking "no" because the noise is clearly overlaid on a larger sine wave. If that's the case then the noise could easily be on the input signal but the Siglent isn't showing it (because of bandwidth limitation or whatever). If the noiseispresent then the Rigol is clearly the better 'scope.Quote from: ebastler on January 22, 2016, 11:23:18 amIt's a pointless "test", yes.

author: rf-loop
author_rank: Super Contributor
timestamp: January 22, 2016, 10:00:00 pm
content: Quote from: Fungus on January 22, 2016, 08:16:40 pmI'm not kid. Do you really think that I do after short around 50 years experience this kind of kids level mistakes. There was Tektronix 50ohm feed thru terminator in Rigol input. AND because Siglent have internal 50 ohm it was NOT in use just for compare apples to apples. This exactly same signal, cable and Tektronix 50 ohm feed thru was also used with Siglent.What bandwidth limit. Siglent SDS1202X have full BW down to 500uV/div sensitivity what is also real analog sensitivity instead of pixel trick). (-3dB over 250MHz @500uV/div)But yes, Rigol is BW Limited related to Siglent. So you can subtract 3dB from Siglent noise just due to double BW in Siglent then they are better face to face.Rigol DS1000Z is like toy in this game if we talk about analog front end quality and noise levels. Also, as you know this Rigol do not have even real 1mV/div analog side sensitivity. (also 2mV/div is least partially trick) It is just poor digital zoom what Rigol try hide using some make up tricks..

author: Fungus
author_rank: Super Contributor
timestamp: January 23, 2016, 12:35:02 am
content: Quote from: rf-loop on January 22, 2016, 10:00:00 pmOk, but does 1mV of noise really make this 'scope useless to people?

author: tautech
author_rank: Super Contributor
timestamp: January 23, 2016, 12:48:12 am
content: Troubleshooting PSU's with ripple especially in quality equipment often calls for a 2 mV or better result.When testing PSU rails it is paramount to also see/measure the frequency of any ripple found to identify its source.Excessive low level front end noise in any DSO can make this difficult.Yes, of course one can use BW limit and various other methods to clean up the signal, but surely a low noise front end is more desirable instead of having to hide the noise.What other signals in the waveform might you miss ? ? ?

author: Fungus
author_rank: Super Contributor
timestamp: January 23, 2016, 12:59:34 am
content: Re: Down and dirty beginners oscilloscope?Quote

author: alsetalokin4017
author_rank: Super Contributor
timestamp: January 23, 2016, 04:49:56 am
content: Quote from: Fungus on January 23, 2016, 12:59:34 amSure... it even has an "AUTO" button, so you don't have to think about anything at all.And such a nice looking display.....

author: Muxr
author_rank: Super Contributor
timestamp: January 23, 2016, 07:48:51 am
content: I still haven't seen a 4ch scope that rivals it in terms of entry level scopes: price/feature/performance. SDS1202X might have a better front end but so it should, it costs more and it only has 2ch.The noise is certainly not a deal breaker for most people, it's nitpicking if you ask me, but if you want better quality you're going to pay more for it.

author: lem_ix
author_rank: Regular Contributor
timestamp: January 23, 2016, 09:28:14 am
content: Quote from: alsetalokin4017 on January 23, 2016, 04:49:56 am10V + 10V equals phase shift? This could be the missing link between general relativity and electromagnetismBack to the original topic, for a beginner any scope will do don't worry so much about it.

author: rf-loop
author_rank: Super Contributor
timestamp: January 23, 2016, 10:00:31 am
content: Quote from: Muxr on January 23, 2016, 07:48:51 amYes. DS1000Z is not bad when we look its price and features. It depends so much user needs. It can use for serious work or hobby just if it meet user needs and user know his instrument and limits. If need cheap 4 channel scope it is true, it is hard to rival, if even need rival (why need - no one can do salary with making or selling these)."Know your instrument" is is very important for avoid situation where user do not know which one he is testing, his test equipment or device under test. (and there, also this "nitpick" about noise is important. Btw, is it nitpick if we talk about camera "front end" noise and quality = lense + digitizer. )I have seen lot of discussion example here in forum where peoples do not know even most low basics and then they wonder if scope is broken or something more fun due to fact they do not know how to use it or do not know even basics about how to connect to device under tests or other way how to transport signal under test to scope... or then comments that I have done some mistake because I see noise in Rigol front end and they religion say it is noiseless.Every single oscilloscope have noise, if it is state of art analog or state of art digital or just lowest quality cheap entry level toy.It need also note that reliable stable low jitter trigger is one of most important thing in oscilloscope. Where to trig reliable if oscilloscope is smearing signal. This vertical noise turn also to horizontal jitter in many cases. Oscilloscope is equipment for inspect vertical things related to time. Noise smudge both axis. As long as signal level is high enough there is not much problem. This leads to question, why there is 1mV/div sensitivity in Rigol. It is just for sales mens they can list it to advertisements. Who can use it and for what? (yes selecting 20MHz BW on and/or doing waveform averaging, something for repeating continuous signals) But also here is: If it meet user needs all is ok.All talk about oscilloscopes quality and if there is this or that quirk and oddity. Bad designs, FW bugs, this and that imperfection.Who talk about users imperfection or lack of knowledge and lack of experience, what is mostly show stopper when they meet something strange and start knocking head to wall and frustrate. Then of course oscilloscope is first quilty but it depends user habit of mind what we have seen also here many times. Sometimes it can see that long long time ago using "camera obscura" highly skilled peoples have take very very nice photographs what most of peoples can never take with even most modern high grade camera today. With DS1000Z is possible to do nearly miracles also. Also with SDS1000X. Skills are important part, not only equipments.Clever people start thinking and perhaps change his test method or example start study and design how to probe device (signal) under test. Finding equipment limits in practice is first thing what need learn if do something more complex than looking with oscilloscope how led is blinking.Also there come manufacturer advertisements. When manufacturer give vision that equipment have example extremely low noise front end and then we can see it is bullshit...If people love his equipment every poor thing in equipment is nonsense. In opposite case even most high level scope one thing may be so that every place this people talk how bad crap this equipment is, nearly like total junk.When my previous R&S spectrum total crash randomly when I adjust RBW its is still state of art equipment and only what I need do is shut it off and on agen and wait it stabilize half hour. Manufacturer have never repaired this bug (perhaps in FW) and now it is so ancient that with this need only live and there is no hope about repair.SDS1000X and also DS1000Z are both new scopes (SDS1000X brand new) that there is coming lot of FW updates to both. But, FW updates do not repair or change HW better. Of course manufacturers do also HW developments and this year same model may have different HW than previously. (or some times reduce manufacture cost as example harmonize production with some other model thet do or select different components). Then someone come and tell that do not buy this crap because in year 2012 its HW have this and that problem what manufacturer have repaired long time ago but still they can classify to crap in year 2016.

author: tautech
author_rank: Super Contributor
timestamp: January 23, 2016, 11:07:33 am
content: Quote from: Fungus on January 22, 2016, 12:33:39 amFor comparison here's a screenshot from an SDS1072CNLdisplaying 5mV RMS p-p sinewave @10MHz from a SDG1010The older SDS1000 series are BW limited at their max vertical settings of 2 mV/div however not at 5mV/div.In both cases the trace shows minimal noise.

author: ebastler
author_rank: Super Contributor
timestamp: January 23, 2016, 11:09:48 am
content: rf-loop -- thank you for your thorough and balanced post. Since you have both scopes in your workshop for testing, could you maybe comment on my earlier remark: To what extent might the different appearance of the noise on the Rigol vs. Siglent scopes depend on different (default) settings for intensity grading and persistence?I am not doubting that the Siglent has lower noise input stages than the Rigol; it seems very unlikely that the significant difference in apparent noise isentirelydue to different display behaviour. But could you let both scopes determine RMS noise on a grounded input as well, to complement the visual demonstration? Thanks!Juergen

author: Fungus
author_rank: Super Contributor
timestamp: January 23, 2016, 12:12:09 pm
content: Quote from: ebastler on January 23, 2016, 11:09:48 amYep.There'sno waythis screenshot is a true representation of the noise on a $400 scope:That line is asingle pixelwide. The 'scope must be doing some sort of averaging/processing of the signal then drawing it in a "join the dots" mode.(I wonder if a DS1054Z has the right combination of options to do the same...)

author: ataradov
author_rank: Super Contributor
timestamp: January 23, 2016, 05:44:15 pm
content: Quote from: Fungus on January 23, 2016, 12:12:09 pmIt sure has. Here is 64 and 1024 sample averaging. Signal comes from SDG1025, same parameters.

author: tautech
author_rank: Super Contributor
timestamp: January 23, 2016, 07:34:48 pm
content: Quote from: Fungus on January 23, 2016, 12:12:09 pmYes, it's called interpolation.No hidden settings, no averaging, no tricks, straight out of the box.Dot made....no significant difference to need to post another screenshot.There are numerous members with similar Siglent SDS1000 models that could attest to this screenshot being a valid representation of the noise performance of this series.And BTW the SDS1072CNL is ~ $300 if you can find stock.http://www.tequipment.net/Siglent/SDS1072CNL/Digital-Oscilloscopes/

author: Fungus
author_rank: Super Contributor
timestamp: January 23, 2016, 08:01:00 pm
content: Well, there you go. A Rigol DS1054Z haszeroinput noise:QED.

author: Muxr
author_rank: Super Contributor
timestamp: January 23, 2016, 08:58:16 pm
content: I did some comparisons between my 500Mhz HP 54610B and my 300Mhz DS2072A (hacked). Signal is coming from Siglent SDG1025.First up no BW limit (2mv/div is as low the HP will go):Same no BW limit on the Rigol:Now the comparison with BW limit on both scopes (Rigol is set to 20Mhz):And finally, averaging and BW limit on:

author: Muxr
author_rank: Super Contributor
timestamp: January 23, 2016, 09:16:57 pm
content: Bottom line is higher bandwidth scopes will be noisier, that's just the nature of it. Also when it comes to SDS1072CNL screens from above, I am not convinced Siglent isn't doing something janky there. That trace looks way too clean.

author: Fungus
author_rank: Super Contributor
timestamp: January 23, 2016, 09:25:11 pm
content: Quote from: Muxr on January 23, 2016, 08:58:16 pmThat's very interesting.And ... if we compare this:With this:They're also quite similar.

author: Fungus
author_rank: Super Contributor
timestamp: January 23, 2016, 09:27:59 pm
content: Quote from: Muxr on January 23, 2016, 09:16:57 pmYep. It's simply not possible to be that perfect.Bottom line: Be suspicious of "zero noise". That's not how it is in the real world.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: January 23, 2016, 09:37:31 pm
content: Quote from: Muxr on January 23, 2016, 08:58:16 pmCareful with these comparisons, the 54610B may have 500MHz analog bandwidth but the sample rate is just 20MSa/s so not enough to appropriately capture noise with frequency components over below 10MHz. For everything above that limit the waveform and the artefacts on the screen will have very little relation to the true signal/noise.

author: Mechatrommer
author_rank: Super Contributor
timestamp: January 24, 2016, 04:49:49 am
content: why the low level signal test with external device and hence produce more validity questioning? why not just left the input unconnected to test the noise floor? or terminated coax at both end for peace of mind? without any external electronics involved? here are the capture, i dont have 50 years of experience as rf-loop has, but what can you question about my test? knowing how rf-loop made posts in this forum since i came in, i can confirm the validity of his test with just danggling input.. DS1054Z has about 1mVpp input noise... about the siglent/instek/owon, i dont know i dont have them, and i dont know if they have some software trick to lower the noise figure. but i doubt it since software trick will appear itself as slower update respond that users can experience but which people like rf-loop doesnt.. but!... just assume siglent is the truly superman super lower noise dso, it has some problems....1) siglent didnt send one unit to dave for testing apple to apple with rigol... or at least they havent made their own extensive review about their scope and publish/advertise it. this is the biggest issue, so potential customers dont get enough exposure and marketing to the scope. poor marketing, you lose. keep the low noise superman figure to yourselfnobody bloody cares nobody bloody knows. rigol? doesnt know how to make superman low noise dso, but knows what hobbiests want and know where to get free marketing..2) siglent's/instek's line of scope that i can search in ebay are several magnitude more expensive than DS1054Z hackable to 100MHz. this can be quickly a no-brainer to fellow hobbiests. we dont have much money to gain from this hobby. we just want to build something that works regardless of the noise figure spec, as long as it is working. if siglent wants to sell this superman scope at double/quadruple/octaruple the price, go sell it to professional experts somewhere, or just a very few bunches of champ here like rf-loop.3) by looking from a few siglent/instek posts here, their scope's GUI is a bit less intimidating, its like old Win3.11 button interface, this can quickly "hosh hosh away you go" potential customers with some basic intuition of how modern GUI should looks like.about the higher rigol noise figure limitation:1) for hoobiests like me, designing a device with 1mVpp noise floor can be an incredible hulk difficult, so it will be a rare occasion that a low noise dso will matters.2) one can use some trick with knowledge to circumvent, or make a way around this. for example with simple math Vdut^2 + Vdso^2 = Vscreen^2. knowing Vdso and Vscreen from the graticules or the eyeball cursor measurement, one can back calculate and estimate the device noise figure Vdut.. the poorman's way..3) even if it matters. by some "luck" if we have a breakthrough changing the world device built with iron man noise figure. we can go rent some $100K scope or spectrum analyzer at fraction of price to accertain the result. are we sure the $600 superman siglent scope and FFT can give the same assurance? if by chance that the siglent/instek is using some unknown trick to lower the dso noise, then this can be bad by deceiving that we have built an iron man device but actually not... maybe someone can test the siglent with known noise source and see if the noise isnt dissappear from the scope view...fwiw... ymmv...

author: tooki
author_rank: Super Contributor
timestamp: January 24, 2016, 02:49:47 pm
content: Quote from: Fungus on January 23, 2016, 12:12:09 pmYup. Enter theAcquiremenu, then choose:Mode: High ResandMem Depth: 12K.(I don't have a signal gen so I can't make screenshots of what that'd look like with that setting.)I think these folks are seeing the Rigol's intensity grading and thinking it's adding noise, when in fact it's just the others not displaying the noise they have.

author: Muxr
author_rank: Super Contributor
timestamp: January 29, 2016, 08:28:08 pm
content: For some more comparison here are some examples from the RTM 1054; Full Bandwidth (the trigger is really struggling with all the noise), 20Mhz Bw limit and Averaging:Also I caught one of Dave's GW-Instek reviews, and in their documentation it states when you're set on 1mv/Div they do limit the bandwidth to 20Mhz, so my guess is Sigilent does something similar.

author: tautech
author_rank: Super Contributor
timestamp: January 30, 2016, 04:45:24 am
content: Quote from: Muxr on January 29, 2016, 08:28:08 pmWhich Siglent?If you are thinking SDS1000X series then you are very wrong as they are full BW (not limited) right down to the 500uV range.https://www.eevblog.com/forum/testgear/siglent-sds1000x-series-oscilloscopes/msg825532/#msg825532

author: Muxr
author_rank: Super Contributor
timestamp: January 30, 2016, 07:05:07 am
content: SDS1072CNL one in this thread.

author: tautech
author_rank: Super Contributor
timestamp: January 30, 2016, 07:16:49 am
content: Quote from: Muxr on January 30, 2016, 07:05:07 amYes, at 2mV/div they too are auto 20 MHz BW limited as signified by the highlightedB.

author: rf-loop
author_rank: Super Contributor
timestamp: January 30, 2016, 02:40:25 pm
content: Quote from: Muxr on January 29, 2016, 08:28:08 pmYou tell 1st image have full BW. Why CH4 indicator show "BW"?AFAIK if there is not any BW limit then there is not BW indicator.

author: cdev
author_rank: Super Contributor
timestamp: January 30, 2016, 03:14:17 pm
content: I got a 1980s Tek 2211 on ebay that has a 500 uv/division vertical sensitivity (in the x10 mode) for $75.And although it is old, its clean and in good shape and appears as far as I can tell to still be within factory specs. With shipping it was a little under $100 I think. It also has some digital features although its quite underpowered by today's standards. But for the money its been well worth it.Obviously you take a risk with older equipment. I don't think its wise to spend more than a fraction of what you would pay for a new one with similar bandwidth - including shipping, on that vintage/level of used scope - (they may not last very long, because of their age, and that is unpredictable) without considering a newer one as probably a better choice...But.. all that said, I like it a lot. Its great having access to one. You can learn a lot more by seeing a waveform than you can from people describing them.If you paid for a working scope and you received a broken one send it back and make sure you do it through ebay - claiming item not as claimed, and not through email elsewhere, then they have to pay for the shipping.

author: Muxr
author_rank: Super Contributor
timestamp: January 30, 2016, 04:43:58 pm
content: Quote from: rf-loop on January 30, 2016, 02:40:25 pmThanks for noticing that, I took a 400Mhz bandwidth limit one as well and decided not to upload it, looks similar to unlimited, I guess I uploaded it by accident, here is the original unlimited.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: January 30, 2016, 04:52:27 pm
content: Quote from: Muxr on January 30, 2016, 04:43:58 pmWow, that's a lot of noise there. What was your setup (source, cable)?Just out of curiosity I did a quick check on my RTM1054:The signal is a 5mVpp 10MHz sine from a Keysight 33522B, going over a H&S RG-58C/U cable with BNC connectors. Source and sink were internally 50ohms terminated.Trigger was absolutely stable.

author: Muxr
author_rank: Super Contributor
timestamp: January 30, 2016, 05:22:09 pm
content: Wow that looks pretty clean, my source is SDG1025, 4mVpp the lowest it will go, 10Mhz, I am actually 1M terminated, 50ohm was worse. I think it's my cable honestly, it's some no name piece of crap. But I did all the other tests with it so I figure I stay consistent.edit: I ordered some new coax cables, I will do a little comparison once they get here.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: January 30, 2016, 05:52:35 pm
content: Quote from: Muxr on January 30, 2016, 05:22:09 pmYou could test without the generator (but terminate the cable) and see if the noise is still there. If not then it might be that the noise is coming from your Siglent generator.

author: rf-loop
author_rank: Super Contributor
timestamp: January 30, 2016, 06:26:52 pm
content: Quote from: Muxr on January 30, 2016, 05:22:09 pmPerhaps there is now external noise. (garbage in = garbage out)I thing R&S can not be so noisy what is in image, even with 500MHz BW. (naturally it can be 7dB over 100MHz scope noise or 4dB over 200MHz scope noise level but it looks now much more. If I compare ecample to 100MHz or 200MHz SDS1000X. This leads to suspect that all this noise is not coming from R&S front end itself.)If you have attenuators it is better run SDG1000 series generator much higher level and drop level to oscilloscope using attenuator between gen and scope. Example 40dB attenuator.In my tests there is mostly used something like Agilent 8644B or old HP8642B or something like these. These are enough clean least for this kind of oscilloscopes. SDG1025 is not good enough for this purpose directly if we are using its nearly bottom levels.Of course can use also empty inputs with just 50ohm terminator (if scope itself do not have 50ohm inputs)1Mohm it can test example if use 50ohm terminator but inserted only half way so that center pin do not connect or just use metal BNC cap so that external EMI can not pollute input. But with real signal we get more nice "reality" to peoples who do not have so much experience but also, it may show something about trigger system, "kill two birds with one stone".

author: rf-loop
author_rank: Super Contributor
timestamp: January 31, 2016, 01:20:48 pm
content: Quote from: Wuerstchenhund on January 30, 2016, 04:52:27 pmHere is same with Siglent SDS2k 300MHz inserted to R&S RTM1054 image just for compare.In this case signal from HP E4421B to blue channel and Siglent SDG5082 to red channel directly and of course both channels 50ohm and M17/84 coaxial cables.SDS2k frequency BW is 300MHz and RTM BW is 500MHz what also mean bit over 2dB difference in natural noise level. (more BW more noise)Of course this is not good compare because also amount of data is different due ti higher samplerate and different wfm/s speed and also possible some differenvcies in image handling. And then, SDG2k do not have real 1mV/div. It is digitally derived from 2mV/div what is highest true analog front end sensitivity. (More new SDS1kX is very different, it have true 500uV/div full BW sensitivity)Of course also in this noise question R&S RTM is very good also if we look other higher end professional class equipments. Siglent is in very different class overall. But if look noise and Siglent here, it is not bad and and trigger is rock solid.