Yet another scope recommendation - Page 1
Forum section: electronics / testgear

author: BenjiBango
author_rank: Contributor
timestamp: June 05, 2024, 04:45:59 pm
content: Hello Everyone.As the title say, I am in search of a good scope for private use and possibly home office with a budget of about €1500 (~$1650). The stuff that usually (about 80%) will be looked at is UART, I2C, SPI, RS232, voltage measurement in the two-digit mV area, and such stuff.A colleague once recommended the MSO5074, which seems to be a pretty decent device, and is apparently regarded as the best sub-€1000 scope. Beyond that, the SDS2104X Plus is recommended.What makes me just pull my hair is that both scope are not that young, and the entries in the forums are not "new". So do they still hold up to more current ones, like the DHO1074 or SDS1104X HD, which is kind of in between both the MSO5074 and the SDS2014X Plus.MSO5074+ Currently cheap (€950)+ 350 MHz probes included+ Samplerate- noise- Pop-Up GUI (overlapping menu/measurments)- most likely no more firmware updates (Last update 2020)SDS2104X+ Apparently decent 10bit mode+ 500 Mhz max (even if only on 2 Ch.)- need to buy decent probes on topDHO1074/SDS1104X HD+ 12bit- "only" 200 Mhz max- need to buy decent probes on top (but less expensive as with the SDS2104X)I tried to read every forums post and watch most likely every video on yt, but either it is at some point to much information or to less... basicly the idiom "You can't see the forest for the trees".Maybe someone wants to chime in and leave their advice.Thanks in advance.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 05, 2024, 05:01:14 pm
content: Far to little info from your side to recommend a scope in the EUR1500 price range.I recently bought an Siglent SDS1104X-E for EUR450 and it's already a much better scope then I need.12-bitters are now becoming more main stream, and having more resolution is nice, but it's also limited as long as the general accuracy of your scope is still 5% or so and the resolution of the display is much lower.I guess you are better off with a relatively cheap "main stream" scope like that, and then save the rest of the money to buy a better scope when you both really need it, and you know what you need. Also, if you have a decent scope, you can also sell it again second hand for a decent price when you want to upgrade your scope.If you want a decent advice for a scope in the EUR1500 price range, you will have to give a whole lot more information about the things you want to do with it.

author: TomKatt
author_rank: Frequent Contributor
timestamp: June 05, 2024, 05:16:44 pm
content: Do you really need a $1K+ scope for that? And as much as a scope capable of checking signal integrity, you might also consider a dedicated LA with more decoding (and pattern triggering) capabilities than a scope can provide if your work involves sniffing data transmissions.I only have experience with my Siglent gear, but I'd think a 200Mhz SDS800X HD series scope would be sufficient for that kind of work. I do a lot of ucontroller projects with I2C / SPI / UART and my previous SDS1104X-E (upgraded to 200MHz) performed more than adequately. I also used a DSlogic Plus LA for serial decoding. Probably less than $600 for the pair.

author: egonotto
author_rank: Super Contributor
timestamp: June 05, 2024, 05:33:01 pm
content: Hello,if you can still wait then aSiglent SDS804X HD € 486,71Siglent SLA1016 Logic Probes € 342,72Siglent SAG1021I € 165,41Together € 994,84could be a good solution.Best regardsegonotto

author: BenjiBango
author_rank: Contributor
timestamp: June 05, 2024, 06:04:59 pm
content: Quote from: Doctorandus_P on June 05, 2024, 05:01:14 pmI'll try to answer as best as I can:Troubleshooting and "verification" for several interfaces with higher bandwidth (uSD, USB, RGMII, LVDS, CSI). Sure some is diffpair, but for a initial test it is sometimes nice to see if this interface works at all. Same for uSD interfaces or Q/OSPI.For glitch searching a zone trigger would be really helpfull or at least the bigger memory.A half decent FFT for discovering unwanted frequencys would also be nice to have.Setting up proper eye digrams. At least I would hope for a more fluent and faster verification of interfaces.Some kind of "future proof" equipment. I would rather have more headroom then fighting with equipment or rebuying stuff. The budget is also rather the upper limit, but of course I looked at the upper boarder. Our go-to scope is a normal Rigol DS1000 which works fine, but you sure feel the limitations here and there (i.e I wrote my own GUI to capture pictures).Quote from: TomKatt on June 05, 2024, 05:16:44 pmSure an LA is handy and nice to have. Especially if it would have more then 16 channels (^^), AFAIK DSLogic have one with 32 channels wich would had been nice a few weeks ago.

author: BenjiBango
author_rank: Contributor
timestamp: June 05, 2024, 06:08:14 pm
content: Quote from: egonotto on June 05, 2024, 05:33:01 pmWhy wait? Is their some upcoming promotion?But to be honest. I am not the biggest fan of internal signal generators or LAs. If they have it fine, if they don't also fine and hopefully the scope is cheaper then ^^I enjoy a USB LA a bit more, as working, labeling and capturing stuff works IMHO a bit better. At least with the scopes I used so far.

author: TomKatt
author_rank: Frequent Contributor
timestamp: June 05, 2024, 06:18:06 pm
content: Quote from: BenjiBango on June 05, 2024, 06:04:59 pmI have the 400MHz DSLogic Plus 16 channel LA and it works great IMO. There is some community bias over the DSLogic company and how they apparently pretty much ripped off Sigrok's software development, but there is no doubt their DSview software works very nicely and the decoder library is quite large. I also like the coaxial test leads that come with it.DSO scopes with serial decoding work fine for basic data monitoring, but if you need to do anything more advanced it was much easier for me with a dedicated LA.

author: BenjiBango
author_rank: Contributor
timestamp: June 05, 2024, 06:29:33 pm
content: Quote from: TomKatt on June 05, 2024, 06:18:06 pmIndeed, and it is usally cheaper then the LA which you need to buy extra (except for some promotions). Thats why I also don't see a big advantage of the internal LAs.

author: coromonadalix
author_rank: Super Contributor
timestamp: June 05, 2024, 06:32:03 pm
content: unless you get some freebies for Serial unlocking, but you do need the hardware ... there is some DIY solutions ...witch in the end is not so economical like @BenjiBango wroteyou have some good LA around

author: Fungus
author_rank: Super Contributor
timestamp: June 05, 2024, 07:39:31 pm
content: Quote from: BenjiBango on June 05, 2024, 04:45:59 pmSounds about right to me. It also has a signal generator and possibility of LA interface.The MSO5074 isn't the "best" at everything but it certainly has the biggest numbers for bandwidth, sample rate, etc. The weak point is noise which gets really noticeable in the single-digit mV range.If the budget is €1500 though, get the Siglent.Quote from: BenjiBango on June 05, 2024, 04:45:59 pmOn the other hand the entry level 'scopes can easily do all that. No need to spend so much money.(unless you need really high speed SPI)That's the sort of stuff I do with my Rigol DHO800 (hacked to get more memory/bandwidth).

author: BenjiBango
author_rank: Contributor
timestamp: June 05, 2024, 08:04:37 pm
content: Quote from: Fungus on June 05, 2024, 07:39:31 pmBut isn't the DHO800 100 MHz max? Or is the bandwidth actually higher?

author: Fungus
author_rank: Super Contributor
timestamp: June 05, 2024, 09:13:52 pm
content: Quote from: BenjiBango on June 05, 2024, 08:04:37 pmMeasured bandwidth ismuchhigher than what the the label says on these 'scopes.The lowest 70Mhz model has about 125MHz measured bandwidth.You can go up to about 280Mhz but that's a bit high for more than 2 channels with a 1.25GHz sampler.I have mine set to "100Mhz" which gives about 200Mhz measured bandwidth.

author: Fungus
author_rank: Super Contributor
timestamp: June 05, 2024, 09:20:06 pm
content: nb. Probing with ordinary probes will completely dominate what you see on screen once you go over about 50MHz.

author: tggzzz
author_rank: Super Contributor
timestamp: June 05, 2024, 09:55:13 pm
content: Quote from: BenjiBango on June 05, 2024, 06:29:33 pmConsider using a scope to verify signal integrity, then flipping to the digital domain and using an LAor protocol analyser.It might be worth your looking at the Bus Pirate 5 for SPI/UART/etc, costs around £40.

author: tautech
author_rank: Super Contributor
timestamp: June 05, 2024, 10:43:04 pm
content: Quote from: BenjiBango on June 05, 2024, 06:08:14 pmDemand has resulted in shortages of stock in some markets.Quote from: BenjiBango on June 05, 2024, 04:45:59 pmQuite understand your confusion.Data pointsSDS2000X Plus is a 500 MHz design.SDS1000X HD is a 200 MHz design.Very similar to use as they both share the same UI as does SDS800X HD which is a different form factor and utilises most of the front panel UI as the SDS1000X-E it evolved from.Keep firing questions and we'll do our best to give good advice.

author: BenjiBango
author_rank: Contributor
timestamp: June 06, 2024, 05:21:39 am
content: Quote from: Fungus on June 05, 2024, 09:20:06 pmNoticed this lately, that's why I moved to "solder-in" probes to have at least a good connection with a short ground path.Quote from: tggzzz on June 05, 2024, 09:55:13 pmThe last times I used the LA was more for power sequencing rather protocol analyzing. Sometimes you just run out of channels.But I will take a look at the Bus Pirate, seams like a nice tool. Thanks for the hint.Quote from: tautech on June 05, 2024, 10:43:04 pmOh OK, understood. Seams like Siglent hit the right spot with that.Quote from: tautech on June 05, 2024, 10:43:04 pmThis is something which kind of puzzled me. From what I saw in the datasheet, and what you also said now is, that the SDS1000 and the SDS800 are basically the same scope. Why bother releasing two of the same? Even more as if compared as 200 MHz versions, one is about €600 more expensive. I mean that with no ill in mind, I was just wondering what might be the decision behind that. I would hardly believe that the bigger display and a second USB port, FlexRay and CAN FD decoder would cost that much. Is there some other reason why the 1000 exists (with this price gap)?

author: tautech
author_rank: Super Contributor
timestamp: June 06, 2024, 05:45:02 am
content: Quote from: BenjiBango on June 06, 2024, 05:21:39 amA cursory look at the datasheet might indicate that and while they have a similar feature set 1kX HD is a lot more scope.Memory specs are slightly different.50 Ohm inputs.Ext trigger BNCProbe autosense < totally wasted as Siglent don't supply sense probes with either model in this series, oh how I wish they did.Additional Decodes and larger display you have mentioned.What can't be conveyed in the datasheet is the build quality and encoder feel which is much superior IMO to SDS800X HD.I too think they are a little overpriced and of any of the current lineup, a candidate for promotional activities to boost sales in the future.Still, if I was to pick one to useallday SDS1000X HD would be my choice in this price segment.

author: 2N3055
author_rank: Super Contributor
timestamp: June 06, 2024, 05:46:45 am
content: Quote from: Doctorandus_P on June 05, 2024, 05:01:14 pmMaybe I don't understand what you said..On new 12 bit scopes accuracy is also much better. For instance SDS800XHD has DC gain accuracy(typical) 0.5 mV/div ~ 4.95 mV/div: ±1.5 %; 5 mV/div ~ 10 V/div: ±0.5 %.Also SDS1000X-E has screen res of 800×480 and SDS800XHD has 1024×600 pix.

author: BenjiBango
author_rank: Contributor
timestamp: June 06, 2024, 06:05:24 am
content: Quote from: tautech on June 06, 2024, 05:45:02 amSure, haptics are sadly no datasheet entriesBut isn't the memory depth the same for the SDS82(2/4)X HD and the SDS1000X HD Series? It just seems to be an actual hardware thing that only the 200 MHz versions have the bigger memory.Quote from: tautech on June 06, 2024, 05:45:02 amAnd you don't happen to know when such activities might occur

author: 2N3055
author_rank: Super Contributor
timestamp: June 06, 2024, 06:46:52 am
content: Quote from: BenjiBango on June 05, 2024, 06:04:59 pmUSB, RGMII, LVDS, CSI are fast serial interfaces. Some very fast.To really check signal integrity on those high BW scope with active probing is needed.

author: BenjiBango
author_rank: Contributor
timestamp: June 06, 2024, 07:13:01 am
content: Quote from: 2N3055 on June 06, 2024, 06:46:52 amSure thing. For that we have a big LeCroy and a Tektronix with proper probes if needed. In this matter, the scope would more used to see if there is any signal whatsoever. So, more a "voltage detector" than a "voltage meter".

author: tggzzz
author_rank: Super Contributor
timestamp: June 06, 2024, 08:17:34 am
content: Quote from: BenjiBango on June 06, 2024, 05:21:39 amHave a look at these pictures of "temporary high speed scope probe “sockets”" (scroll down to that phrase)https://entertaininghacks.wordpress.com/2020/07/22/prototyping-circuits-easy-cheap-fast-reliable-techniques/The only type of probe it makes sense tosolderto a circuit is a homebrew Z0 resistive divider, but that requires 50ohm termination at the oscilloscope. (Well I suppose soldering a piece of coax is OK for low-level audio signals)

author: BenjiBango
author_rank: Contributor
timestamp: June 06, 2024, 08:49:12 am
content: Quote from: tggzzz on June 06, 2024, 08:17:34 amI think I didn't provide enough context with that. I use the "Probe-To-BNC" adapter to connect a thin coax cable (RG178 or somethig) which will then be soldered at the point of interest. Which might not be quite as good as the method in your link, but less bulky.

author: Fungus
author_rank: Super Contributor
timestamp: June 06, 2024, 09:33:49 am
content: Quote from: BenjiBango on June 06, 2024, 07:13:01 amYou certainly don't need a 1500 Euro 'scope for that.

author: 2N3055
author_rank: Super Contributor
timestamp: June 06, 2024, 10:21:27 am
content: I would go with 500Mhz (more like 650MHz -3dB in real life on 2ch) and 50Ω inputs for purposes stated.

author: tggzzz
author_rank: Super Contributor
timestamp: June 06, 2024, 09:11:51 pm
content: Quote from: BenjiBango on June 06, 2024, 08:49:12 amIf you do that then there will be reflections causing the displayed voltage to be frequency dependent. The frequency of the nulls depends on the length of the piece of coax, shorter->higher frequency of first null. Use an online VSWR calculator to find those frequencies; better simulate it with a Spice or any of the online equivalents.

author: BenjiBango
author_rank: Contributor
timestamp: June 07, 2024, 07:14:40 am
content: Quote from: tggzzz on June 06, 2024, 09:11:51 pmDidn't thought of this to be honest. I just compared it with the ground spring and lead, and the results was more of the range of the spring, but without needing a third arm to hold everything in placeBut I will have a look into that, thanks.

author: tggzzz
author_rank: Super Contributor
timestamp: June 07, 2024, 09:56:16 am
content: Quote from: BenjiBango on June 07, 2024, 07:14:40 amThe other, obvious, point is that coax will load your circuit. For low frequencies that will appear to be a capacitance, for high frequencies it will be the characteristic impedance, 50ohms.For a standard "high" impedance *10 probe, it is worth calculating the tip impedance (i.e. R//C) at relevant frequencies. Relevant for a digital signal is determined solely by risetime.Then calculate the same for a "low" impedance *10 resistive divider probe. Note the quotation marks.Have a look at the references inhttps://entertaininghacks.wordpress.com/library-2/scope-probe-reference-material/