Can't decide on an oscilloscope - Page 1
Forum section: electronics / testgear

author: jure94
author_rank: Newbie
timestamp: August 07, 2024, 02:12:45 pm
content: Yet another post about this but I simply can't decide what to get so I am hoping to get some insight.I am looking to buy an oscilloscope and the cost is the primary limiting factor. Ideally, I would be looking for something in the 500€ range but I am willing to go more if price/performance makes sense.I certainly need 4 channels and I don't really require LA or waveform output but I know many options include them by default or can be unlocked.I was first looking at the Rigol MSO5000 range as I like that it has 8 GSa/s and physical buttons for each channel. However, I realize that newer models are now available which may be better suitable. Specifically the DHO800/900 with their 12-bit ADC.Then I also started looking at Sigilent which is similarly priced and now there are simply too many options.Regardless of what I would get, I would get the base model and upgrade it. While you do get better probes depending on the model I can buy a better probe if/when required.As I do all kinds of designs I need to look at all parameters. Let's say for digital I would like to measure signals with 2ns rise time and for analog, I would like to see 1mV changes with confidence. Although my analog designs are all quite slow, below 10 MHz. I also do power supplies on occasion.What would someone with experience recommend?I was looking at MSO5074 which is on sale but significantly more expensive. So I think I really need to decide between DHO804 (hacked to DHO924) or SDS804X HD (hacked to SDS824X HD). Which of the two has a better analog performance? Rigol does come with better probes but I would need to buy better probes in any case.

author: Fungus
author_rank: Super Contributor
timestamp: August 07, 2024, 03:10:01 pm
content: If looking at 1mV signals is a primary requirement then forget the MSO5000.Measuring a 2ns rise time needs approx. 150MHz bandwidth. The DHO804 can easily do that if you hack it.Seeing the exactshapeof that signal with a passive probe is difficult though. The Rigol probes are quite good but all passive probes introduce artifacts at those frequencies.

author: NE666
author_rank: Frequent Contributor
timestamp: August 07, 2024, 03:31:07 pm
content: If you do need fast digital, nothing in your list gets close to the MSO5000. Plus you get a basic AWG and have the option of an MSO LA later, if you find you need it.If you must have a low-noise front-end, then the MSO5000 is out of the question. As the owner of two Rigol scopes (MSO5000 and DHO1000), I'd strongly suggest that you look at the Siglent SDS800X HD series. Rigol's attitude towards software quality and commitment to fixing issues leaves an unpleasant taste in the mouth.

author: TomKatt
author_rank: Frequent Contributor
timestamp: August 07, 2024, 04:35:47 pm
content: Siglent SDS804X HD is probably the best scope under $500 right now. Consider a dedicated LA later if you need one.

author: tggzzz
author_rank: Super Contributor
timestamp: August 07, 2024, 04:39:22 pm
content: Quote from: jure94 on August 07, 2024, 02:12:45 pmGood to see someone specify risetimes rather than bandwidthIgnore the samples/s specifications, which are no more than marketing penile extensions. The two scope specs that matter are risetime and ENOB (i.e. effective number of bits).Your analoguedesignsare for below 10MHz, and hope yourimplementationsare tooBe particularly aware of the way bog-standard scope probes interact with digital edges; damped 100MHz oscillations are normal, unless great care is taken with probing technique.Standard warnings for beginners: never ever disconnect a scope's protective mains earth, and understand why HV differential probes exist and when they must be used.Consider using a scope to ensure digital signal integrity (voltages, timing, monotonicity), then you can flip to looking at digital using digital domain tools (logic analyser, protocol analyser, printf() ).If you want to look at the last 0.1% of an analogue signals risetime (e.g. an opamps settling behaviour), then you need to be very sure the scope's inputs aren't overloaded. Recovering from overload can take averylong time.

author: jure94
author_rank: Newbie
timestamp: August 07, 2024, 05:34:08 pm
content: I would prioritize its use for measuring analog circuits over digital ones. For digital ones, I mostly use my logic analyzer anyway but on occasion, I have a need to see the signal in more detail when debugging. However, for 95% of cases, a separate LA is a better option for me.For now, it looks like Sigilent is the better option. And they specify ENOB but I couldn't find this information for Rigol.I also found a detailed review (I still need to go through everything) which is extremely helpful:https://www.eevblog.com/forum/testgear/sds800x-hd-review-demonstration-thread/Just as a side note, I do have quite a bit of experience with oscilloscopes but until now I made do with a cheap USB-based one (PoScope) at home for my projects.I do have a higher-end oscilloscope available at work (Keysight 6000 series, 4ch 6GHz) that I can use for anything my hobby grade purchase won't be suitable but I would like to minimize such cases.Thank you for your help. If anyone has both I would be happy to hear their opinion as well. I couldn't find a direct comparison of both.

author: tggzzz
author_rank: Super Contributor
timestamp: August 07, 2024, 06:00:38 pm
content: Quote from: jure94 on August 07, 2024, 05:34:08 pmExcellent! Clearly you are someone that understands and thinks, and can work out how to "do more with less"I wish more people were like that!

author: EC8010
author_rank: Frequent Contributor
timestamp: August 08, 2024, 03:51:48 pm
content: Quote from: tggzzz on August 07, 2024, 04:39:22 pmAbsolutely. Most good 'scopes are 8-9 ENOB because that's the right amount. I suspect a £500 'scope will be a little less.Something else that is important (but difficult to specify) is the proportion of time the 'scope spends capturing waveforms as opposed to housekeeping. Cheap 'scopes are very poor on this. A very simple (but revealing) test is to put the 'scope into XY mode and feed two channels with stereo music. What you should see (and would on an analogue 'scope) is a pulsing ball of wool having a continuous thread. Poor 'scopes will show breaks in the wool and maybe even noticeable updates to the picture.

author: tggzzz
author_rank: Super Contributor
timestamp: August 08, 2024, 05:51:26 pm
content: Quote from: EC8010 on August 08, 2024, 03:51:48 pmJust so.Lissajous figures are also revealing; a couple of oscillators or AWG could be the source. A rotating sine/cos signal at various frequencies ought to look like a smooth and clean circle.If an AWG isn't available then it might be possible to create an audio file containing, say, left: 1kHz and right: 2kHz.

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 08, 2024, 06:01:02 pm
content: Quote from: EC8010 on August 08, 2024, 03:51:48 pmModern scopes, especially in a lower budget, will not update fast enough for oscilloscope music to display perfectly. For that test, a modern scope will need the memory set at one of the lowest settings for a good/fast update rate. An old analog scope that's good at that lest, fails miserably on 1000 other metrics compared to a modern scope.The only modern scope I've seen so far with an impressive update rate with X-Y oscilloscope music display is the Magnova from Batronix. Nobody buying a $500 scope should care about this at all.

author: nctnico
author_rank: Super Contributor
timestamp: August 08, 2024, 06:12:25 pm
content: Quote from: EC8010 on August 08, 2024, 03:51:48 pmFor real world measurements the speed of XY mode isn't relevant anyway. XY mode is useful for looking at small, slow phase variations between two repetitive signals.

author: EC8010
author_rank: Frequent Contributor
timestamp: August 08, 2024, 06:29:06 pm
content: It's not the speed of XY mode itself, it's that to do XY mode the 'scope has to trigger, record, and process waveforms, so it's a very quick way to compare 'scopes side by side.

author: tautech
author_rank: Super Contributor
timestamp: August 08, 2024, 08:52:08 pm
content: Quote from: EC8010 on August 08, 2024, 06:29:06 pmThere's a lot more to the modern DSO than just the signal path to the display.Intuitive UI and menusFeature set and the most important of all, the triggering capability.

author: 2N3055
author_rank: Super Contributor
timestamp: August 08, 2024, 09:05:03 pm
content: Quote from: EC8010 on August 08, 2024, 06:29:06 pmNo it is not.

author: Fungus
author_rank: Super Contributor
timestamp: August 08, 2024, 09:22:26 pm
content: Quote from: EC8010 on August 08, 2024, 03:51:48 pmNot these new 12-bit Rigols/Siglents.The noise levels and resolution of this new generation is impressive.FWIW: From what I've seen in EEVBLOG threads I don't think there's much difference between the two. Certainly not enough to base a purchase decision on.

author: Bud
author_rank: Super Contributor
timestamp: August 08, 2024, 09:39:52 pm
content: Quote from: tautech on August 08, 2024, 08:52:08 pmNone of this matters if there is no knobs.

author: tautech
author_rank: Super Contributor
timestamp: August 08, 2024, 09:45:00 pm
content: Quote from: Bud on August 08, 2024, 09:39:52 pmSDS6000L models have none yet are easy to operate with a mouse, easier again if one is already familiar with the same UI and menu structure used in most of Siglents other DSO's.

author: nctnico
author_rank: Super Contributor
timestamp: August 08, 2024, 10:00:29 pm
content: If you need a mouse to drive a touchscreen DSO, then there is something seriously wrong with the UI design. A properly implemented touchscreen UI is better (as in more effective and comfortable) compared to using a mouse.

author: tggzzz
author_rank: Super Contributor
timestamp: August 08, 2024, 10:14:30 pm
content: Quote from: nctnico on August 08, 2024, 10:00:29 pmWhile I tend to agree, there's also some truth that trackballs bugger your thumbs, mice bugger your wrists, and lightpens/touchscreens bugger your shoulders.So, choose your poison Lightpens were popular before mice. They fell out of favour for good reason.Personally my quibble would be with...Quote from: tautech on August 08, 2024, 09:45:00 pm

author: Bud
author_rank: Super Contributor
timestamp: August 08, 2024, 10:14:48 pm
content: A mouse to operate a scope? Do not miss apointments with you psychiatrist, folks.

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 08, 2024, 10:16:25 pm
content: Quote from: nctnico on August 08, 2024, 10:00:29 pmHe specified the SDS6000L which is a rackmount device that doesn't come with a screen.

author: egonotto
author_rank: Super Contributor
timestamp: August 08, 2024, 10:37:21 pm
content: Hello,but omitting the monitor is very expensiveSDS6054L costs € 7,380.00.SDS6054A costs only € 6.480,17Best regardsegonotto

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 08, 2024, 11:11:29 pm
content: Quote from: egonotto on August 08, 2024, 10:37:21 pmDifferent tools for different uses. You can rackmount a series of SDS6000Ls to get a ton of inputs if that's something you need.I can't afford either, so whatever.

author: tautech
author_rank: Super Contributor
timestamp: August 08, 2024, 11:25:54 pm
content: Quote from: egonotto on August 08, 2024, 10:37:21 pmYes I have one of each, SDS6054L and SDS6204A but they are different tools for different tasks.I would've liked the 8ch SDS6058L but that was another price level again.While the feature set is quite similar, SDS6000L models can do more and offer a higher precision platform and more connectivity.