Requesting advice on selecting a new oscilloscope - Page 1
Forum section: electronics / testgear

author: kuon
author_rank: Regular Contributor
timestamp: February 08, 2019, 05:38:28 am
content: Hello,I currently have a tektronix TDS 1012C-EU oscilloscope and I am in the need of an upgrade.I've worked only with older HP oscilloscope in the past and presently with my tektronix. I don't have experience with modern "feature packed" DSO/MSO.I read the forum extensively, but I am still a bit confused by all the options.I get the general idea that chinese products are good and more feature packed, but might not be as good as the "classics" (lecroy, tektronix...). I got a GW-instek precision bench top multimeter but I am not that impressed with it, it does the job and seems to hold to the advertised precision, but it has some design problems (units are really small on the VFD display, no temperature probe support (I didn't pay attention that it was only on the higher model, so this is my fault, but for the price it didn't occur to me that it wasn't included), has an annoying relay doing a click-click noise which is getting on my nerves when doing continuous measurement, the supplied probe cables are not flexible enough in my opinion, ...). I am not saying it is bad, again it does the job, but it does not feel like a precision instrument.I guess it will be simpler if I just list my requirements:At least 2 channelsUART/SPI/I2C decodingI use my current oscilloscope extensively to measure current (with a shunt resistor) consumption of battery powered systems (like the microcontroller powering up, doing thing and shutting down after a few ms), but currently I just look at the spike on the screen and evaluate it. I did export the waveform to USB and did the actual calculation on my PC a few times, but it's really time consuming. So being able to do integral on a waveform directly on the oscilloscope would be really cool, like saying " what is the energy consumed by this spike?". I found this (https://www.eevblog.com/forum/blog/eevblog-662-how-why-to-use-integration-on-an-oscilloscope/) but it seems to be a high end DSO. This would be really handy, because it would allow me to do real time optimization to the code running on the microcontroller and watch the result in real time without having to "guess" if it's an improvement or not.For bandwidth, fastest signal I worked with was 25Mhz and I read you need 5 times that, so I'd say 200Mhz should be well enough but depending on the price I might stay at 100Mhz, I am mostly after the decoding and math features.PC backend would be great. I looked into the pico scope, but I am a bit wary of having only the PC backend. While I get that the possibilities with the PC backend are infinite, turning knobs seems much more comfortable, especially when probing different signals on a board in rapid succession while adjusting the scales and triggers. This might not be a real issue, as I found sigrok which supports a lot of DSO.Silent. I worked with older HP oscilloscope that where noisy, never again. I don't know if modern DSO have fans, but I don't want them if possible. I'd rather have a giant enclosure with heat sinks than a smaller one with fans.My budget is in the 2000-5000$ range.

author: DaJMasta
author_rank: Super Contributor
timestamp: February 08, 2019, 06:03:25 am
content: You probably want 4 channels or more, you're not going to be decoding much SPI on just two, methinks.Every modern DSO will have a fan, so you've got to find one that's not as bad.... sometimes this is considered by the manufacturer, but people's tolerances vary, so it's probably best to hear it on video.Given your budget and your relatively low bandwidth requirement, I'd probably look at Rohde & Schwarz for their scopes. Some of the highest end feeling lower priced scopes and with lots of features and attention to detail. You can get better value for dollar for basic acquisition performance and such, but if you don't mind spending for the product has really gone into the details of the design (like acoustics), you'd probably appreciate the more premium feel of those kind of units. Otherwise, there are tons of scopes that will fit your bill, and probably a few 4 channel budget options that come in way below $1000. Virtually every modern one will have exporting to USB, and most now have USB connections, LAN connections, or both (or as an option) for automation and data export. Especially with the higher budget, I'd look towards 10-12 bit scopes rather than just 8 bit converters - will give you more detail and dynamic range with lower noise and should be well within your budget.Worth mentioning that it's also not that hard to swap a fan if you don't mind voiding that warranty sticker. Higher end scopes generally have faster digitizers which generate more heat - so sometimes they need pretty high airflow fans that just can't be totally silent, but scopes designed for it or that aren't generating a ton of heat can have the fan upgraded to something really quiet.

author: capt bullshot
author_rank: Super Contributor
timestamp: February 08, 2019, 06:22:42 am
content: The modern variety from Rohde & Schwarz and Keysight would be my choice - look which models are within your budger and trade features vs. bandwith. So a higher model range with less BW might have a similar price tag to a higher BW model of lower model range, but might offer more features or aquisition speed or whatever.Some of them were advertised as "silent" (still having a fan, but at < 30dB, whatever this means in practice).Some of them have a LAN connection, so one can hope for easy transfer of screenshots / data to a PC.Don't know about the details of the math functions, having seen a big LeCroy beeing able to integrate power (integration of a math function channel), and another one (afair a Rigol) having integration and multiplication, but not beeing able to integrate power (since it couldn't integrate the math function).Anyway, after a bit of using the Rigol (that wasn't a low end model), I wouldn't buy a chinese one for the same reasons you mentioned - feature laden, specs OK, but also buggy and laggy user interface, not so intuitive to use.

author: Psi
author_rank: Super Contributor
timestamp: February 08, 2019, 08:38:03 am
content: If you decide to get a Rigol try the model out first.Some of the new ones have so much lag between control movement and screen movement that they will drive you mad.

author: tautech
author_rank: Super Contributor
timestamp: February 08, 2019, 10:12:37 am
content: Quote from: kuon on February 08, 2019, 05:38:28 amWelcome to the forum.Let me up-end your list.QuoteYou really don't need to spend that much to get a DSO that can do most of what you want.QuoteTick.QuoteWould a custom input attenuation in conjunction A/div be a solution ?QuoteThere's no need to pay for decoders like some brands require.QuoteSure, but if you can easily get the data out of the scope you can manipulate it to suit your needs.QuoteThis is where most equipment with any real processing power will fall short. If the noise of a modern PC is acceptable then that's about the same as most modern DSO's.....some but not a howling gale noise.Have a look at SDS1104X-E in this review and see if it will meet your needs.....I think it might come close and with a significant saving for you.https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review/

author: tggzzz
author_rank: Super Contributor
timestamp: February 08, 2019, 10:37:55 am
content: Quote from: kuon on February 08, 2019, 05:38:28 amConsider using a logic analyser. They are very cheap and avoid some of the problems with scope decodes.QuoteFor analogue signals, you will know the required bandwidth. For "digital" signals that statement is false: the only parameter that matters is the transition time.For pointers to the theory, plus practical demonstration, seehttps://entertaininghacks.wordpress.com/2018/05/08/digital-signal-integrity-and-bandwidth-signals-risetime-is-important-period-is-irrelevant/QuoteFar more than necessary.Have a look at the Digilent Analog Discovery. It combines several instruments (14bit >10MHz scope, AWG, logic analyser, pattern generator), and post-processing to plot bode/nyquist/spectrum analysis diagrams. Plus you may be able to create a virtual instrument to do your specific processing.

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 08, 2019, 10:59:19 am
content: Quote from: kuon on February 08, 2019, 05:38:28 amdont get Rigol then you'll be dissapointed. slow update rate of math trace and not anywhere near real time is just unacceptable. and as someone said, GUI laginess could drive you nuts, but i found workarounds and get used to it. enough said.

author: kuon
author_rank: Regular Contributor
timestamp: February 08, 2019, 12:14:41 pm
content: Thanks a lot for your replies.QuoteI discovered it a few days ago, it is very informative, way more than stackexchange electronic QA site which I was browsing before.QuoteHaving zero lag is one of the reason why I want a instrument with a display and not something PC based.QuoteI am not sure what you mean here.QuoteYeah that make sense. I read the 5 times somewhere, but didn't really think about it.Right now I am trying to get a general idea of the different brands. Their history, philosophy, position in the market....There is something I didn't mention because it is not technically relevant, but as someone mentioned the brand charging for options, I guess I'd share this bit.I am mainly a programmer, I have been doing electronics as hobby for some time, but been doing it for a living for only about a year. Before that, I've done about 20 years of coding, mostly open source. I'm sharing this, because it means that I have a very strong feeling towards open source and "hackability" in general. I saw some oscilloscope models that can be unlocked for higher bandwidth or decoding options with a software key, that makes me, "uneasy". Don't take me wrong, I understand and respect the work that goes into the R&D of those devices, but I'm firmly against DRM and other "locking mecanism" of any sort. Of course it might not be relevant here, but the more open the company is, the more happy I'll be to buy from them. (I am not saying the firmware should be open source, I understand this kind of business is still way behind in term of open source, but "general company philosophy and market practices").

author: BillB
author_rank: Unknown
timestamp: February 08, 2019, 01:07:14 pm
content: Quote from: kuon on February 08, 2019, 12:14:41 pmProviding additional software based features for extra-cost is a standard way to provide product line differentiation these days. While manufacturers in this market probably aren't going to embrace complete open-source any time soon (Theyareusing Linux under the hood), there are some that are more forgiving regarding hack-ability of their devices than others. They turn a blind-eye to glaringly obvious hacks (such as keeping well known root credentials for some devices, etc.)I have the scope tautech mentioned (Siglent SDS1104X-E) and given that it's easy to hack it to an SDS1204X-E, the value for the money is hard to beat.

author: SWR
author_rank: Regular Contributor
timestamp: February 08, 2019, 02:04:32 pm
content: Hi KuonI had similar requirements and chose the GW Instek MDO-2204EX oscilloscope.It's around $1.800 and you get 6 instruments in one compact package.Instrument 1: Digital Storage Oscilloscope 4ch 200MHz/1Gs.The measured analog bandwidth on my scope is 289MHz using the Leo Bodnar generator.Plenty fast 120Kfps update rate.4x10M point memory with up to 29.000 segments and extensive search functions.Extensive math functions:Source Ch1-4,Ref1-4Measurement Pk-Pk,Max,Min,Amp,High,Low,Mean,CycleMean,RMS,CycleRMS,Area,CycleArea,ROvShoot,FOvShoot,Freq,Period,Rise,Fall,PosWidth,NegWidth,Dutycycle,FRR,FRF,FFR,FFF,LRR,LRF,LFR,LFF,Phase,RPRFShoot,FPREShoot,+Pulses,-Pulses,+Edges,-EdgesOperators +,-,*,/,<,>,<=,>=,==,!=,||,&&Functions Intg,Diff,Log,Ln,Exp,Sqrt,Abs,Rad,Deg,Sin,Cos,Tan,Asin,Acos,AtanApp Bode plot: 20-25MHz, log gain & phase 10/15/30/45/90pt/dec, >80dB dynamic rangeApp Data logging: waveforms, screenshotsApp Digital filtering: LP/BP/HP,trackingApp DVM: 3 digit DC/DCrms/ACrms, 5 digit Frequency/Duty-cycle, floating windowApp Go-NoGo: compare, violation stop/count, separate entry/exit, toleranceApp Mask: compare, violation stop/count(save), auto/manualCalibration: Probe compensation, Signal Path Compensation, Full calibrationEasy screenshot and trace save to USB for report generation.Instrument 2:Serial bus decoder: UART/SPI/I2C/CAN/LINFlexible trigger with bin/oct/hex including don't care (wildcards).Flexible memory search in up to 29.000 segments: bin/oct/hex including don't care (wildcards).Instrument 3: 500MHz spectrum analyzerHigh resolution 1M point FFT with very fast update rate.Easy UI with Centre/Span or Start/Stop frequency setting.You save time by not having to switch back to scope mode to adjust.Sample/Min/Max/Avg, RBW auto/1-5K:1, Lin/bDV/dBmWindows:Rectangular: single shotHanning/Hamming: periodicBlackman: amplitudeInstrument 4: Dual 14bit 25MHz Arbitrary Waveform GeneratorSine,Square,Pulse,Ramp,DC,Noise,Sinc,Gaussian,Lorentz,Exp.Rise,Exp.Fall,Haversine,Cardiac.Arbitrary with on screen editor or download from PC.Functions: AM,FM,FSK,SweepInstrument 5: 5000 count DMMVdc,Vac,Idc,Iac,Ohm,Beep,DiodeThermocouple in°C/F with characteristics B/E/J/K/N/R/S/THere you can use the thermocouple you are missing in the other multimeter.Instrument 6:Dual 1-5V 1A PSU0,1V step3,3/5V presetsHere you can power small development boards like an ESP32 or similar.All instruments can be remote controlled from LabView via USB if you want to automate measurements.In my view all this for $1.800 is a bargain.Good luck with your decision.Best regardsSoren

author: nctnico
author_rank: Super Contributor
timestamp: February 08, 2019, 02:59:40 pm
content: You can also buy the GW Instek MSO2104 and uphack it to have the spectrum analyser and more bandwidth.

author: tggzzz
author_rank: Super Contributor
timestamp: February 08, 2019, 04:16:36 pm
content: Quote from: kuon on February 08, 2019, 12:14:41 pmVery much so.Stackexchange is OK for the boring ephemeral questions that can be answered quickly and simply, e.g. "Which button do I press to make SquirdleFish v5.4 frobble the widget from left to right?Stackexchange (and imitators) is,by design, bad for discussions, bad for contentious/subtle topics, and bad for basic theory.

author: maginnovision
author_rank: Super Contributor
timestamp: February 08, 2019, 05:07:36 pm
content: Since you want silent I would suggest you go try them out in a quiet room. Also no open source oscilloscope is worth the price, at least not now. On silence I would suggest the rtb2000 from R&S. Quite a few of us here have them as we got fully unlocked 4 channels for 2k. Another option would be something like the entry level keysight 3000t since they have the #1 UI responsiveness but also fairly low memory. They can be hacked though so even though base scope costs a bit you can get your moneys worth.

author: tautech
author_rank: Super Contributor
timestamp: February 08, 2019, 08:01:03 pm
content: Quote from: kuon on February 08, 2019, 12:14:41 pmFrom the review thread previously linked:https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review/msg1555936/#msg1555936Also, follow the link in that post to see how that might apply for current measurements using a SDS1104/1204X-E.

author: Keysight DanielBogdanoff
author_rank: Unknown
timestamp: February 08, 2019, 08:32:10 pm
content: Like @maginnovision mentioned, our 3000T are pretty great and quite quiet. We also just came out with the new DSOX1204G that uses the same chipset as the 2/3/4/6000 scopes but would be in the low range of your budget.

author: Andreas
author_rank: Super Contributor
timestamp: February 08, 2019, 08:37:05 pm
content: Quote from: kuon on February 08, 2019, 12:14:41 pmI think you will like the PicoScopes: you get also a API and a SDK to build own applications (besides Windows + LINUX-version) from them for the USB-scopes.The support is also open for "new features" (delivered usually at the next regular update with the free software).Look at the PicoScope 5444D: fanless design USB 3.0 powered 4 channels for SPI, 512 MB memory and the best: high ADC resolution for dynamic current measurements.with best regardsAndreas

author: kuon
author_rank: Regular Contributor
timestamp: February 09, 2019, 05:46:34 am
content: Thank you for all your messages, that is very helpful.I'll try to arrange something with a friend who works at the EPFL here (the tech school close to me), to test a few different scopes, especially the pico one.

author: tggzzz
author_rank: Super Contributor
timestamp: February 09, 2019, 08:52:03 am
content: Quote from: kuon on February 09, 2019, 05:46:34 amAt this point, that will probably clarify your mind and shape decision more thancontinueddiscussion.Have fun, safely: don't forget probing technique and the different types of probe.