Owon 14-bit USB scopes - Page 1
Forum section: electronics / testgear

author: balnazzar
author_rank: Frequent Contributor
timestamp: October 11, 2022, 10:23:42 am
content: Hi. I was eyeing those Owon USB scopes who are advertised as 14-bit.The only actual source of information I managed to find is this review:https://youtu.be/LzNmIVRB0lYThe review is about the 2ch version (but also 14 bit) and it's not a Dave-like review, but still it shows how the software behaves, and it seems not that bad (generally, the software is the Achilles' heel of these cheapo usb scopes).Are the 14 bits real? I mean, the corresponding (100 MHz, 1 GSa/s) Picoscope is just 8 bit and costs three times that thing [~1300 vs. ~450, prices in euros and VAT included].Thanks.

author: rf-loop
author_rank: Super Contributor
timestamp: October 11, 2022, 11:54:31 am
content: Quote from: balnazzar on October 11, 2022, 10:23:42 amPerhaps you have not watched this video. In video, starting from 2:40:14bit mode max 100MSa/s14Bit mode BW: 20MHz.And old thread in EEVblog tell more:https://www.eevblog.com/forum/testgear/owon-vds6102a-pc-oscilloscope-with-14-bit-adc-wifi-and-usb-support-(battery)/Specifications are in end of user manualhttps://files.owon.com.cn/probook/VDS6000_Series_2CH_user_manual.pdf

author: jasonRF
author_rank: Regular Contributor
timestamp: October 11, 2022, 02:48:21 pm
content: I don't know about the hardware, but the software has no features. Zero waveform arithmetic, so you cannot even subtract two channels. Likewise, no FFT of any kind. I even emailed the company earlier this year and verified that it had none of those features, although they indicated that they are planning on adding them. If/when they do add an FFT you will need to look closely at how long it is. For example, according to the user manual the 8-bit vds3102 only has a 2k FFT so gives only 1k frequency bins, even though it has 10 MSamples of memory.I have downloaded both the vds3102 and vds6102 software, and the features line up with the documentation. No math menu of any kind on the vds6000 software, and the vds3102 software gives you no choice of any kind for the FFT length. It is fixed.So even if the 14-bit hardware is great, if you want to do anything more than just look at waveforms and do basic measurements on them you will need to write your own software and just use the scope as an acquisition system. For me it was a deal-breaker.I ended up on Ebay and managed to pick up a used (and out of production) multi-resolution Picsocope 5244B for $457 US delivered.By the way, which 8-bit picoscope were you looking at that was priced that high? They have a ton of models.EDIT: Hi Balzannar. I just realized that you started this thread - surely as part of your quest to find a quiet scope. It looks like you are going down the same path I did earlier this year. good luck!jason

author: coromonadalix
author_rank: Super Contributor
timestamp: October 11, 2022, 03:01:06 pm
content: Wait until they make 24 bit scopes ... a war of numbers

author: jasonRF
author_rank: Regular Contributor
timestamp: October 11, 2022, 03:49:07 pm
content: Quote from: coromonadalix on October 11, 2022, 03:01:06 pmYup! But the numbers do have meaning as long as the software/firmware and analog hardware are good enough to make good use of the bits. I don’t know about the hardware, but the Owon firmware/software are not currently good enough, in my opinion.When i was shopping for a used Picoscope I was just looking for a good deal on 2-channel 100-200 MHz scope. I considered high-resolution, extra channels and MSO capabilities to be ‘bonus’ features that would be nice but not worth paying a lot extra for. Had a good deal on an 8-bit 2-channel scope shown up first, i would have been happy with it for sure. But I do like the extra bits. I usually run 12-bit resolution, since you only lose a factor of 2 in maximum sample rate in order to gain the 4 extra bits.24-bits do have their place. I use a 24-bit audio interface for analyzing distortion in audio signals.CheersJason

author: balnazzar
author_rank: Frequent Contributor
timestamp: October 11, 2022, 07:34:19 pm
content: Quote from: rf-loop on October 11, 2022, 11:54:31 amYep, I listened at this. It's a limitation, but with respect to a pure 8-bit scope, you still have the chance to observe low-ish frequency signals with great accuracy. Consider that the25 MHz, 4ch Pico sells for 110 eur more (and, right now, is unavailable).Quote from: rf-loop on October 11, 2022, 11:54:31 amThanks, at a first search that didn't pop up..

author: balnazzar
author_rank: Frequent Contributor
timestamp: October 11, 2022, 07:44:50 pm
content: Quote from: jasonRF on October 11, 2022, 02:48:21 pmHi Jason, thanks for the tips! I was looking at the 2408B. It's nowhere to be found right now, except for Farnell that has a single 2408B for sale, priced 1135eur+vat(22%). Any other 4ch Pico with at least 100 MHz bw costs much more.The limitations are quite heavy indeed, but I was attracted by the Python API.I don't know... The Picos are of course much, much better software-wise (and almost surely hardware-wise as well, no matter the resolution..) but they are either nowhere to be found, or priced insanely high, even on Ebay.. Since there is low availability, people who own them don't want to sell cheap, and I understand them...

author: jasonRF
author_rank: Regular Contributor
timestamp: October 11, 2022, 10:14:22 pm
content: Quote from: balnazzar on October 11, 2022, 07:44:50 pmI do not know how it works to order from Europe, but tequipment.net has 2407B in stock. The spec is 70 MHz, but the 2407b and 2207b models that were tested in that picoscope 2000 thread (the one I linked in your other thread) had >100 MHz bandwidth if I read their posts correctly. I don’t know if that sounds reasonable to you or not, as we each have our own requirements and comfort levels. There is an eevblog discount at that store as well.When I was shopping earlier this year I also noticed that there were no good deals on used 4-channel Picoscopes.I am not familiar enough with the Owons to know about a Python api. I just know that they have scpi interface, and I believe there are Python packages online that are designed to do scpi over Python. My programming skills are not so great (unless it is Matlab/Octave which I use all day at work) and I really do not enjoy it, so as a hobbyist I had no interest in a device that would require me to write a bunch of code just to do FFTs or other tasks that I do all the time. But it may be just fine for you.Edit: i did find some python scripts that the manufacturer posted on github, but it was not clear if those are for the older vds3000 scopes, or if they were also for the v newer vds6000a scopes.

author: egonotto
author_rank: Super Contributor
timestamp: October 12, 2022, 08:27:16 am
content: Hello,An important point is that the Picoscopes do not have a fine adjustment of the vertical scale.Best Regardsegonotto

author: balnazzar
author_rank: Frequent Contributor
timestamp: October 12, 2022, 09:56:40 am
content: Quote from: jasonRF on October 11, 2022, 10:14:22 pmIt's a tough call. Tequipment reports that the 70B costs EUR 1,008.19, and that VAT and import duties will be calculated just before finalizing the purchase. I think we are looking at some 1300-1400 eur, from which you can cut off 6% of EEVblog discount. It's too much for my pockets.. I think there are no good deals right now due to scarcity..One thing I could do would be purchasing both the 4ch Owon and the Pico 05A (25 MHz, 200 eur). That would be 650 eur all included. The Owon would give me 4 channels, albeit with the limitations you accurately described. The 05A, on paper offers nothing more that the AD2 I already have, but would give me the possibility to practice with the Pico ecosystem, see if I like it, so that I can decide if I want a more serious Pico for when I'll have the money..

author: balnazzar
author_rank: Frequent Contributor
timestamp: October 12, 2022, 09:57:48 am
content: Quote from: egonotto on October 12, 2022, 08:27:16 amThanks, egonotto. That's just for the 2000 series, or it's an issue even for higher tier models like the 3000 and the 5000 series? Thanks!

author: egonotto
author_rank: Super Contributor
timestamp: October 12, 2022, 10:45:48 am
content: Hello,I believe all scopes. But with the 12 bit or 16 bit devices, that's not so bad anymoreBest regardsegonotto

author: jasonRF
author_rank: Regular Contributor
timestamp: October 12, 2022, 07:22:12 pm
content: As far as I can tell, you can control the axes scaling, but that does not change the gain in the physical front-end. To be honest, even the axis scaling is a little clunky. I never use it, and for what I do it doesn’t matter very much. But I could see that some people may really want that feature. Does the Owon have it? From the user manual it doesn’t look like it does.This is not the only quirk about Picoscopes. The main one that sometimes causes me trouble is the fact that they have no automated measurements of time-delays (or phase delays) between signals in two different channels. They really have no excuse for leaving that out.Jason

author: balnazzar
author_rank: Frequent Contributor
timestamp: October 12, 2022, 09:31:04 pm
content: Quote from: jasonRF on October 12, 2022, 07:22:12 pmGood to know that, thanks. It's a bit disappointing.

author: balnazzar
author_rank: Frequent Contributor
timestamp: October 20, 2022, 05:33:24 pm
content: Quote from: jasonRF on October 11, 2022, 02:48:21 pmMh, I bought an Owon VDS1022i because it's a littleinsulatedscope for just 119 eur (Amazon). Consider that comes with two probes.Look, this is just the calibration waveform, but it can do the FFT and some math:

author: agusugid
author_rank: Contributor
timestamp: February 04, 2023, 03:09:17 am
content: Inside VDS6102A

author: jasonRF
author_rank: Regular Contributor
timestamp: February 04, 2023, 01:57:02 pm
content: Quote from: agusugid on February 04, 2023, 03:09:17 amNice photos! It looks pretty good inside, and as expected has the HAD1520 ADC chip. I would be interested in hearing your experiences using the scope, and whether they update the features/software.Enjoy!Jason

author: agusugid
author_rank: Contributor
timestamp: February 06, 2023, 08:36:37 am
content: I think it has decent hardware.Pretty hot after + 30 minutes.You must connect it directly to USB3 port, using hub will not work in my experience.Can only use a good quality USB cable, the included cable works fine (thick cable), using thinner cable lead to error or excessive noise.Using included power supply is the best way.Noise is pretty low. In 2mV/Div, measured below 2mV without test probe attached.Can not clearly see differences between 8 bit or 14 bit mode, all seem in hi res modeand the difference in sampling rate made it even harder to see the difference. Can not set the sampling rate manually.No lag in various memory depth in all bit depth mode.Self calibration runs relatively fast with some relay clicking. Autoset in slow side.Can not hear relay clicking sounds when changing the coupling mode, maybe use solid state realy??The software maybe the weakest point in this scope, very basic functionality, even cannot change background color and wave colorRegardsAgus

author: 2N3055
author_rank: Super Contributor
timestamp: February 06, 2023, 02:51:41 pm
content: Quote from: agusugid on February 06, 2023, 08:36:37 amIs that P-P or RMS ?Are you sure it is 2mV? That is not really low noise but very high...

author: agusugid
author_rank: Contributor
timestamp: February 06, 2023, 11:42:28 pm
content: Image attachedin 14 bit mode and 8 bit Mode

author: YurkshireLad
author_rank: Frequent Contributor
timestamp: February 07, 2023, 12:06:56 am
content: Quote from: jasonRF on October 11, 2022, 02:48:21 pmCan you use generic oscilloscope software with the Owon? Eg.https://www.roomeqwizard.com/features.htmlhttps://www.sillanumsoft.org/

author: ci11
author_rank: Regular Contributor
timestamp: February 07, 2023, 01:47:15 am
content: Quote from: coromonadalix on October 11, 2022, 03:01:06 pmActually, there has been a 24-bit scope for sometime now - the National Instruments 5922 in PCI of PXI interface. It varies its bit-depth between 16- and 24-bit, with sampling rate between 15MS/s and 500kS/s. So while it is extremely quiet with a noise floor at about 6µV, it's really more suited to being configured as a data collection VI or frequency domain work, not time domain as a scope is often called for. What's more, if used with an interactive UI like NI's InstrumentStudio running on their controllers, be prepared to wait as you crank those virtual knobs - it can be painfully S L O W. Not cheap either.

author: agusugid
author_rank: Contributor
timestamp: February 07, 2023, 02:57:08 am
content: Quote from: YurkshireLad on February 07, 2023, 12:06:56 amI don't think the softwares will work with owon scope.For REW I will use hi res sound card

author: agusugid
author_rank: Contributor
timestamp: February 07, 2023, 03:02:24 am
content: Quote from: jasonRF on October 11, 2022, 02:48:21 pmMath function is available. You can do - + * / with both channelsFFT also availale, but I think Owon should not give the function as it so useless

author: 2N3055
author_rank: Super Contributor
timestamp: February 07, 2023, 08:36:56 am
content: Quote from: agusugid on February 06, 2023, 11:42:28 pmThat is not 2 mV, it is around 200uV RMS which is more normal.....This is amount of noise that, for instance, has Rigol DS1054Z (unlocked to 100MHz) that is an 8bit scope.It is still not low noise but OK. Low noise would be quite less than 100uV RMS. There are quite a few inexpensive 8 bit scopes (Micisg and Siglent comes to mind) that have much lower noise than that.So Owon is 14 bit but noise levels are at just OK-ish entry level 8 bit scope level.. And it is not even that inexpensive.For general purpose work, DS1054Z (or Micsig or Siglent) would be better choice overall..

author: agusugid
author_rank: Contributor
timestamp: February 07, 2023, 09:09:57 am
content: Quote from: 2N3055 on February 07, 2023, 08:36:56 amI never said that the noise is 2mVAnd for the noise, I compared it with other USB scope in this price range .... not the bench scope like siglent or rigol which I believe has lower noise.RegardsAgus

author: 2N3055
author_rank: Super Contributor
timestamp: February 07, 2023, 09:37:09 am
content: Quote from: agusugid on February 07, 2023, 09:09:57 amWell you did say it.. but never mind. We could have misunderstanding here.In Eleshop Owon VDS6102A is €322.31 +VAT..My point is that is not really THAT low cost..Rigol DS1102Z-E and Siglent SDS1202X-E are same price range and better in every respect. And Siglent SDS1202X-E will have 3x less noise... Both will be fully featured "real" scopes that are proven to be working really well. Siglent SDS1202X-E will also have good FFT with 1MPts..Unless you got your Owon for half the price, it wasn't a good deal at all, in my opinion..

author: agusugid
author_rank: Contributor
timestamp: February 07, 2023, 10:23:04 am
content: Quote from: 2N3055 on February 07, 2023, 09:37:09 amWhat kind misunderstanding did you mean?my post is still there to read. But yes, I agree, never mind.I got mine about USD 280 incl. shipping. Curiosity does have its price. Rigol 1054Z about USD 470 in local shop here.I have bench scopes too, but don't think the bench better in every aspects compared to this USB scope. At least in portability and larger display the USB scope has its advantage.For speed and simple measurement, this Owon scope is not lacking compared to entry level bench.But in general if you have more budget and can afford bench scope like Siglent or Rigol, that's still a better choice in my opinion.Best regardsAgus

author: jasonRF
author_rank: Regular Contributor
timestamp: February 07, 2023, 12:37:21 pm
content: Quote from: agusugid on February 07, 2023, 03:02:24 amThat is an improvement. The subtraction function is of course key for a lot of measurements, and also a place where the extra bits can really help.I just looked through the manual on the owon site, and they haven't updated it yet to include the math. Does it let you pick the size of the FFT? Or does it work like on the vds3102, where you only get a 2k FFT so just 1k frequency points? I usually find that I want a pretty long FFT to really get the information I am looking for, but even a 2k FFT can be useful.jason

author: agusugid
author_rank: Contributor
timestamp: February 08, 2023, 05:43:27 am
content: Quote from: jasonRF on February 07, 2023, 12:37:21 pmAttached the panel control for FFT. So Useless. Can not even show 1 khz from the channel 1 wave.

author: 2N3055
author_rank: Super Contributor
timestamp: February 08, 2023, 07:37:17 am
content: Quote from: agusugid on February 08, 2023, 05:43:27 amYou have to make it sample at lover sample rate if you want it to show anything at all. This is common mistake. You have only 10 periods on the screen. Set timebase to something like 10ms/div, not 500us/div and see if something starts to show up. In general FFT won't show good results (even on good implementation) if you can see details of signal in time domain..Play with timebase a bit.But yeah FFT is not very good.

author: agusugid
author_rank: Contributor
timestamp: February 08, 2023, 12:19:53 pm
content: Just realize that the software can not auto detect the peak freq and put it in the center of the window. No autoscale at all in vertical or horizontal axis.Have to manually slide the fft to find the peak freq.As you said, the more samples, the better8bits vs 14bits shows different fft resultBest RegardsAgus

author: jasonRF
author_rank: Regular Contributor
timestamp: February 08, 2023, 02:07:51 pm
content: FFT looks usable - and seems like it must be larger than 2k.I see you are in peak detect mode. I have only used FFTs in normal sampling mode on my scopes. Given how oversampled you still are it might not matter too much, but does the FFT look much different in normal vs peak detect? I would especially be curious whether it changed the levels if the 2nd and 3rd harmonics.Jason

author: agusugid
author_rank: Contributor
timestamp: February 09, 2023, 02:07:09 am
content: Quote from: jasonRF on February 08, 2023, 02:07:51 pmImage attached. I think the difference is minimal.Agus

author: agusugid
author_rank: Contributor
timestamp: February 10, 2023, 02:28:39 am
content: Thermal imaging for VDS6102A after 30 minutesRoom temperature about 30CADC and FPGA are the hottest spot

author: agusugid
author_rank: Contributor
timestamp: June 23, 2023, 02:37:31 pm
content: Difference between 14bit vs 12bit vs 8 bit