Analog vs digital X-Y mode - Page 1
Forum section: electronics / testgear

author: Miti
author_rank: Super Contributor
timestamp: March 22, 2018, 02:17:52 am
content: Just for fun, I guess no digital can beat an analog scope at X-Y.

author: tautech
author_rank: Super Contributor
timestamp: March 22, 2018, 03:27:01 am
content: Link to file please so we can all play.

author: james_s
author_rank: Super Contributor
timestamp: March 22, 2018, 03:34:22 am
content: File? Isn't it a piece of hardware? I have a scope clock that I built from a kit years ago, the particular one I have is a standalone device but I've seen boards meant to connect to an existing scope.As much as I love my Tek DSO, the XY mode is pretty hopeless, that is one of the few things where analog wins hands down.

author: Miti
author_rank: Super Contributor
timestamp: March 22, 2018, 03:49:34 am
content: It's a kit.http://www.dutchtronix.com/ScopeClockH3-1-Enhanced.htm

author: Tom45
author_rank: Frequent Contributor
timestamp: March 22, 2018, 04:03:32 am
content: So why do digital scopes do so poorly in X-Y mode?

author: ataradov
author_rank: Super Contributor
timestamp: March 22, 2018, 04:07:20 am
content: Quote from: Tom45 on March 22, 2018, 04:03:32 amPixels are much more visible. I'm sure some of those $5000 R&S scopes will look much nicer.And I'm pretty sure scope manufacturers simply don't care, just like with FFT function. I personally never had to use XY mode for anything in my entire life.

author: egonotto
author_rank: Super Contributor
timestamp: March 22, 2018, 04:52:39 am
content: Hello,I think most DSO are good in streaming. They capture many samples and after they postprocess the samples. In x-t-mode they "know" the best samplerate.But in x-y-mode they dont know the best sample rate. If you have 10 Hz than a sample rate of 20kHz would be good, but if you have 10Mhz than you need a much higher samplerate.Perhaps they take 1 sample and process this sample and so on, but this slows the whole.Best regardsegonotto

author: Performa01
author_rank: Super Contributor
timestamp: March 22, 2018, 05:45:16 am
content: Setting up X/Y mode is different for analog vs. digital.For analog, we only need to take care of the channel gain.For digital, we also need to set the timebase to make sure at least one full signal period is captured (but also not too many more). This also determines the sample rate which is usually plenty high enough, hence not a problem.Whatisa problem though is the low amplitude resolution of an 8-bit digital scope.8 bits means 256 steps, but most scopes allow some overscan and e.g. only 200 steps are visible on the screen. On a 400 pixel high display, this means two pixel per amplitude step. In X/Y mode, the same is true for the x-direction. A picture composed of 2x2 pixel clusters on a low resolution 400x400 screen area just cannot look pretty, full stop.A DSO with at least 10 bits and high-res display should be able to produce reasonably nice X/Y figures.

author: tautech
author_rank: Super Contributor
timestamp: March 22, 2018, 07:25:20 am
content: We'll all know when DSO's have really come of age when they can handle Jerobeam Fenderson's oscilloscope music.https://www.youtube.com/user/jerobeamfenderson1Yummy stuff.

author: rf-loop
author_rank: Super Contributor
timestamp: March 22, 2018, 10:14:35 am
content: Also with digital scopes there is one thing what also may affect result. There is some different methods to do X-YSome DSO's may use direcft XY plot method (read X and Y ADC and plot point and repeat)Some DSO may use normal acquisition to sampling buffer (just as in YT mode) and then process it for X-Y "image")This last method make possible to do many automatic measurements also in XY mode. Rise times, pos and negative width, periods - whole buch of measurements including full sample resolution rise and fall times, pulse widths etc etc..I do not know any reason to plot analog clock to oscilloscope display - exept fun. Oscilloscope is tool mainly for inspect more or less unknown signal. But of course if want entertainment box there is lot of many kind goods for this purpose. Much better than oscilloscope. I do not even know where XY is useful today. For what?Yes I have played with clock and other images with my previously owned couple of Tek7000 series and some Tek portable tool as 2465 etc.

author: Fungus
author_rank: Super Contributor
timestamp: March 22, 2018, 02:13:58 pm
content: Quote from: tautech on March 22, 2018, 07:25:20 amMy cat loved it.

author: Tom45
author_rank: Frequent Contributor
timestamp: March 22, 2018, 02:49:23 pm
content: Quote from: rf-loop on March 22, 2018, 10:14:35 amOr instead of plotting points, draw a vector from Xn-1, Yn-1to Xn, YnThere is still the question of what sample rate to use. But I don't see any downside to oversampling. So why not sample as fast as possible.But after thinking about it, perhaps the tricky part is how to emulate phosphor persistence.

author: David Hess
author_rank: Super Contributor
timestamp: March 22, 2018, 03:16:05 pm
content: Quote from: Tom45 on March 22, 2018, 04:03:32 amDSOs have six problems with X-Y mode:1. Non-index graded displays cannot be anti-aliased and most DSOs with index graded displays do not anti-alias anyway or anti-alias poorly; this becomes an additional source of quantization noise. Note that the analog examples above show a raster displayed on a vector display device producing further aliasing on the DSOs. A true vector implementation would look better on both types of oscilloscopes.2. DSOs suffer from quantization noise from the digitizer which is usually handled poorly in X-Y mode. High resolution mode should solve this. Average acquisition mode should also solve this unless it lowers the update rate.3. Most DSOs produce display updates by batching record length groups of samples. If the vector generation time does not fill the record length evenly, then the display updates either miss or overlap sections. "Phosphor" type DSOs still update the display in batches determined by the number of samples between display updates.4. DSO display refresh and update rate is orders of magnitude slower than the continuous update rate of an analog oscilloscope. This should not matter above about 60 Hz but combined with 3 above it becomes a problem.5. Almost all DSO displays have a much lower resolution per area than an analog CRT. Many old CRT DSOs operated at 254dpi (100dpc) and could produce a pretty good vector display in X-Y mode except for the record length and update rate issues described above despite lacking anti-aliasing.6. Most DSOs do not support a Z-axis (intensity) input so all of the vectors run together. The Rigol example above shows this.These issues with DSO XY mode could be fixed to produce a display limited only by the display device itself but it is hardly a high priority.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 22, 2018, 03:35:28 pm
content: Hey, I'm impressed those did as well as they did.X-Y is a notoriously hard problem, and low on the list of priorities to address.Tim

author: james_s
author_rank: Super Contributor
timestamp: March 22, 2018, 04:21:53 pm
content: I use XY when working on vector arcade boards, a scope is more convenient than having one of the (hard to find) 19" vector monitors and a power supply producing the multiple oddball voltages they require on the bench. At least I did before I built a 5" vector monitor for one of my other projects.

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: April 28, 2018, 04:11:57 am
content: I have to monitor an I-Q pair of a demodulated signal while the signals are also being captured. My Rigol DSO is great for Y-T plots and I love the compact size and weight. But the X-Y function absolutely sucks (the FFT isn't all that great, either.) I use my 1974 vintage Tektronix dual 100MHz just for the X-Y plots and they are gorgeous. I can tell what's going right/wrong with my instrument. With both 'scopes, I get to look at 6 signals which happens to be how many I have

author: Scratch.HTF
author_rank: Regular Contributor
timestamp: April 28, 2018, 04:36:15 am
content: Despite the retrace lines on the digital scope, it still looks impressive.

author: vk6zgo
author_rank: Super Contributor
timestamp: April 28, 2018, 07:41:55 am
content: Quote from: Miti on March 22, 2018, 02:17:52 amInteresting that the old "tedious"210 does better than the much more capable DS1054Z.

author: ataradov
author_rank: Super Contributor
timestamp: April 28, 2018, 07:43:58 am
content: Quote from: vk6zgo on April 28, 2018, 07:41:55 am210 has a horribly slow display, so it probably contributes quite a bit to the "analog" feel.But it seem like DS1054Z does not even attempt to blank the transitions, so may be some configuration of intensity will improve things.

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: April 28, 2018, 11:50:50 pm
content: Hopefully the linked videos will convince the nay-sayers that analog X-Y rocks(They are too big to attach. The links are to OneDrive).https://1drv.ms/v/s!AhmR5if7W0HCjcJG8SPwrOfTWF-grghttps://1drv.ms/f/s!AhmR5if7W0HCjcJFalJzpym6hx4C_AA bit of description is probably necessary. There are two videos of a real/imaginary pair of signals from a photodetector (after demodulation) for light scattered by electrically charged nanoparticles moving in a liquid. A laser illuminates the sample. The first video shows just random Brownian motion from the particles. In the second video, an electrical field is turned on and off every five seconds or so. When it is on, the nanoparticles move toward the electrode of opposite charge. Movement of the particles causes a Doppler shift of the laser light. The X-Y trace indicates the amplitude and the optical phase difference of the light. The phase is proportional to the position of the particles. When the field is on, you can see "circles". One complete circle is one hertz. In terms of position, it is approximately 1 micron. The frequency of the circles is a perhaps 5 to 10Hz. That's a change of 5 to 10 parts in 100 trillion.Rock on, 48-year old 475 scope!!!(Sorry the videos are upside and grainy).

author: nctnico
author_rank: Super Contributor
timestamp: April 28, 2018, 11:56:51 pm
content: Are there any loss-less wav files available for the clock so people can try without needing the actual hardware?

author: CopperCone
author_rank: Super Contributor
timestamp: April 29, 2018, 01:16:56 am
content: for constallation diagrams

author: rstofer
author_rank: Super Contributor
timestamp: April 29, 2018, 01:42:15 am
content: Over in a distant corner of the electronics sandbox, a few of us play with analog computing. Not many people over here...X-Y mode is critical. We usually use one integrator to provide the X axis and the output drives the Y axis. There are cross-coupled differential equations that draw a kind of egg-shaped pattern. Not a circle, more like one that has been stomped on. It's interesting to print two channels of Y(t) but more interesting to plot the simultaneous values of X and Y.FWIW, the classic example is the Predator Prey problem. As the rabbit population increases, eventually there will be more foxes. More foxes will drive down the rabbit population which will reduce the fox population allowing the rabbit population to increase, and so on.When I want X-Y done well, I use my Analog Discovery 2. Among other things, I get a better screen shot.

author: mtdoc
author_rank: Super Contributor
timestamp: April 29, 2018, 03:25:58 am
content: Quote from: rstofer on April 29, 2018, 01:42:15 amLotka–Volterra equations

author: rstofer
author_rank: Super Contributor
timestamp: April 29, 2018, 03:55:42 pm
content: Quote from: mtdoc on April 29, 2018, 03:25:58 amExactly! I need to read through that document. About half way down they give the X-Y plot that I was discussing above. Both populations are displayed on a single graph.These equations don't have to be put into an actual analog computer. MATLAB does a fantastic job of modeling the required integrators (2) and gain stages. Simulink gives the same answers without all the op amps. But I like the old-school approach. There's just a warm fuzzy feeling as the integrators integrate, the multiplier multiplies and the gain stages do their thing.Attached is the Simulink modelNote that the model is pretty superficial. As the article points out, the assumptions are probably not realizable. Notably that the Prey can grow without bound because there is always adequate food. The model could be improved to account for an exponential growth asymptotic as some logistic limit.In my view, the X-Y mode more appropriately displays the interaction between the populations. The Y(t) mode is useful but the X-Y mode drives the point home.

author: chirality
author_rank: Contributor
timestamp: May 21, 2018, 10:56:07 pm
content: I'm curious, of all the <$2000 DSOs on the market as of 2018, which make/models do XY-mode the best (by best, I mean most analog-like)? Keysight? Tek? Rhode & Schwarz? Siglent?

author: tautech
author_rank: Super Contributor
timestamp: May 21, 2018, 11:25:46 pm
content: Quote from: chirality on May 21, 2018, 10:56:07 pmIn a few days we'll know how well the SDS1*04X-E XY mode has been improved as it's just been enhanced in the latest firmware.

author: chirality
author_rank: Contributor
timestamp: May 22, 2018, 12:24:30 am
content: Quote from: tautech on May 21, 2018, 11:25:46 pmThat's great to hear. Please keep me updated! I'm in the market for a DSO and the Siglent is attractive. I just definitely don't want to see an XY mode like this:

author: tautech
author_rank: Super Contributor
timestamp: May 22, 2018, 12:36:33 am
content: Quote from: chirality on May 22, 2018, 12:24:30 amYes, to properly evaluate it it needs be videoed.The new FW I've mentioned is discussed here:https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review/msg1555936/#msg1555936It's not up on the Siglent websites yet but should be in the next few days.

author: CopperCone
author_rank: Super Contributor
timestamp: May 22, 2018, 02:08:22 am
content: Quote from: chirality on May 22, 2018, 12:24:30 amThat looks like some kind of 1970's casino sign from Las Vegas.

author: Rich@RohdeScopesUSA
author_rank: Frequent Contributor
timestamp: May 22, 2018, 03:08:05 am
content: Quote from: chirality on May 21, 2018, 10:56:07 pmThere are several videos of the RTB2000’s XY mode available from 3rd party reviewers, including one pretty thorough one here:Mikes Electric Stuff has also played around with it a bit with some unique combinations:https://mobile.twitter.com/mikelectricstuf/status/959025632830197761-Rich

author: nfmax
author_rank: Super Contributor
timestamp: May 22, 2018, 07:47:41 am
content: Last year I had occasion to use XY mode on my Keysight MSO-X 2024A, to characterise the transfer function of an opto-isolator circuit (tweaking for best noise margins with lowest power dissipation). It worked beautifully, including a simulated 'spot' following the signal - which was a triangle output from the built-in generator. First time I'd ever tried XY mode, though!

author: tautech
author_rank: Super Contributor
timestamp: May 22, 2018, 08:49:40 am
content: Quote from: tautech on May 22, 2018, 12:36:33 amWell I've managed to find a copy of the new SDS1004X-E series FW and the XY mode is dramatically improved.With lowest memory depth set it really flies for a cheap DSO.But unfortunately even just a 10s video is 30+MB on my phone so it's too big to post here.Tonight might be YT A/c setup night.Done.https://youtu.be/wUCdaVq3kL0

author: borjam
author_rank: Unknown
timestamp: May 22, 2018, 10:38:05 am
content: Quote from: tautech on May 21, 2018, 11:25:46 pmAny plans for the two channel SDS1202X-E? Seems that despite belonging to the same "family" firmware development is diverging a lot.

author: tautech
author_rank: Super Contributor
timestamp: May 22, 2018, 11:01:02 am
content: Quote from: borjam on May 22, 2018, 10:38:05 amThe last 1202X-E FW was back in Jan so any improvements it supports that's been added to the 4ch X-E should follow in time. The divergence is due to the substantial additional functionality the 4 ch models provide and the need to get all that stuff right.

author: bd139
author_rank: Super Contributor
timestamp: May 22, 2018, 11:10:37 am
content: Someone should try this on an HP 546xx. They have a superior X-Y mode. Not bad for 1994...https://youtu.be/D2uEvRPd4w8

author: chris_leyson
author_rank: Super Contributor
timestamp: May 22, 2018, 12:33:21 pm
content: Nice tutorials from Jerobeam Fenderson

author: nctnico
author_rank: Super Contributor
timestamp: May 22, 2018, 12:40:14 pm
content: At least some DSOs can do color grading in XY mode:

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: May 22, 2018, 11:25:17 pm
content: I've put together a short sequence of videos to show why an ancient analog scope beats the crap out of a budget DSO in XY mode. There's no audio but there's a description which I've included here, too.Quote

author: alsetalokin4017
author_rank: Super Contributor
timestamp: May 23, 2018, 03:40:18 pm
content: Well, to be fair, it is possible to get a _slightly_ better display of the ScopeClock on the Rigol DS1054Z than what was shown in the OP.But it definitely looks better on the analog scopes.

author: joeqsmith
author_rank: Super Contributor
timestamp: May 24, 2018, 04:34:30 am
content: I had someone ask me about the X-Y mode on one of my old scopes. I was not sure what they were asking so I ran is various settings. One comment I had was about the sparse amount of data. I suspect they were thinking audio and I was looking at much higher frequencies.Is the goal here just use use a scope for art? I watched some of these fancy YT videos like the one linked above. I then tried using Labview to put together a simple program to use the sound card but it was far too slow. I ripped some of the audio tracks from YT and then tried it with some of the dedicated PC sound card scopes. Looks like they may do a decent job. YT compresses the audio so the graphics don't look very impressive but the dedicated programs far exceed what I could do with Labview. I tried playing these files into one of my scopes and could post a clip but it's not very impressive with the YT compression. At best you would have some idea on the update rate of my old scopes.As mentioned, I think if the goal is to benchmark the visual effects, a standard audio clip may be a good place to start.The letter 'D'

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: May 24, 2018, 12:57:45 pm
content: Quote from: joeqsmith on May 24, 2018, 04:34:30 amSometimes science is artI created the clips with preset waveforms from my function generator (such as chirp, FM modulation etc). The signals were demodulated about a fixed frequency to generate a quadrature pair which are the XY signals (like a lock-in amplifier).My real-world application is demodulation of a modulated photodetector signal from nanoparticles moving in a liquid. The phase information in the signal relates to the position of the particles. If the particles are just moving randomly, the XY trace will show a random walk. If there is linear motion such as due to movement in an electric field, the phase will change linearly and the XY trace will rotate. Observing this directly and live on a CRT scope in XY mode is tremendously valuable. It tells me if there are issues with sample or hardware and I can "see" when the particles are moving due to the electric field (which is the primary purpose of the experiment). Without this, I'd be working "blind". It is analogous to the use of vectorscopes for video. For my particular application, the frequencies are in the audio band.

author: joeqsmith
author_rank: Super Contributor
timestamp: May 24, 2018, 04:48:13 pm
content: Quote from: bd139 on May 22, 2018, 11:10:37 amHunting around this site, I found were this same post was made in 2012 or so. Someone had the raw file but the links were dead. Doing a quick Google search, the are still available if we wanted to use this as some sort of benchmark. Just search for oscillofun.flac.Quote from: JohnnyMalaria on May 24, 2018, 12:57:45 pmIf you wanted to detail a setup, we could use this as a test case as well. Or if you wanted to model it in software and create a raw WAV file, that may make things even easier and possible allow more people to run it for you.

author: joeqsmith
author_rank: Super Contributor
timestamp: May 25, 2018, 12:37:19 am
content: Link to the oldest thread I could find showing oscillofun.https://www.eevblog.com/forum/suggestions/audio-signals-quality-in-x-y-mode-what-is-important-what-is-not/msg164751/#msg164751

author: james_s
author_rank: Super Contributor
timestamp: May 25, 2018, 12:45:42 am
content: I use the XY mode on my 465B scope while working on vector arcade game boards, it's a lot more convenient than trying to rig up a fullsized vector monitor which are rare and valuable in addition to being bulky, fragile and requiring some odd voltages.

author: joeqsmith
author_rank: Super Contributor
timestamp: May 25, 2018, 01:12:04 am
content: Oscillofun does appear to a much cleaner source. I took a few screen shots while it was playing.

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: May 25, 2018, 03:11:38 am
content: Audio is too restrictive because of the limited bandwidth. It precludes the ability to compare technologies in the 100kHz+ range and sub ~20Hz. It also introduces variation due to different soundcard characteristics such as THD, equalization, DAC jitter etc.A 2-channel DDS arbitrary waveform generator allows for better control, consistency and wider bandwidth (DC to many MHz). In my case, I have a FeelTech FY2300 that goes to 20MHz. It's basically the same as the 6600 but with a lower max. frequency and a different physical form.The simplest test is to set up a sine wave on both channels at the same frequency somewhere in the 10s of Hz region with a 90deg phase difference between them. Then introduce a small frequency difference (say 1Hz). In XY mode, an ellipse should appear to "rotate" at 1Hz. Increase the frequency difference and compare the scopes. At some point, the DSO will show its weakness due to the buffered acquisition. Increase the frequency of both channels to the next decade and repeat the frequency difference observations. Repeat this for each decade. You could also have one channel at 3 times the frequency of the other to generate a Lissajous figure and then add small frequency differences to cause rotation.Now choose an arbitrary waveform for one channel and keep the other as a sinusoid. Do a similar investigation of decade and frequency difference. At lower frequencies, the CRO will prevail but at higher decades the DSO will start to show detail that is too fast for the human eye to pick out on the CRO. This is because the weakness of the DSO at lower frequencies becomes a benefit at higher ones.In my case, I have a '74 Tektronix CRO and a 2017 Rigol DS1104Z.In essence, you need to compare both technologies at the frequency range that is important to you. For me, it's a no brainer to use both and pick the most suitable one for your application.Playing around with different combinations of arbitrary waveforms on each channel as a function of decade and frequency difference is a revealing exercise.I am curious to learn how the more expensive DSOs fair across the frequency range.

author: CRTbrain
author_rank: Contributor
timestamp: August 27, 2024, 03:05:52 pm
content: digital scope do poorly with XY because they inherently have slow update rate. R&S has the fastest update rate with MXO4 and MXO5....but they don't yet support XY mode...and maybe their XY mode, when released, will be in SW or maybe in HW. All digital scopes so far have XY done in SW.

author: tautech
author_rank: Super Contributor
timestamp: August 27, 2024, 03:47:59 pm
content: Quote from: CRTbrain on August 27, 2024, 03:05:52 pmThings have changed some since this thread started and would do well to carefully examine how to achieve excellent DSO XY performance from this thread:https://www.eevblog.com/forum/testgear/oscilloscope-music-on-dsos-post-your-results/

author: pdenisowski
author_rank: Super Contributor
timestamp: August 27, 2024, 04:41:24 pm
content: Quote from: CRTbrain on August 27, 2024, 03:05:52 pmI guess you'll just have to wait and see

author: wolfy007
author_rank: Frequent Contributor
timestamp: August 29, 2024, 03:09:04 pm
content: Digital scopes dont do so bad these days, even some of the cheap ones, below are a few examples from various age groups and price range using the Dutchtronix clock (my favourite XY test), all of which show the clock fairly smoothly once you get the setting right.

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 29, 2024, 04:04:09 pm
content: I couldn't say how legit, but the Batronix demo video for the Magnova oscilloscope had what looked like X-Y mode that impressed me more than any other modern scope so far.

author: Phil1977
author_rank: Frequent Contributor
timestamp: August 29, 2024, 06:38:37 pm
content: Does anyone know how much dead time the current digital scopes have in xy mode?AFAIK modern xy mode is a spin-off of the digital phosphor technology. Many digital scopes even keep the trigger activated in XY-mode. This means, each time the trigger is activated, a snapshot of the signal on X and Y is taken and summarized to the display matrix.But this also means that the time between the snapshots is just plotted to the screen.In the end we have (at least) three main differences comparing analogue to digital:- Analogue is without any dead time. XY-mode does not even need an electron beam return blank.- Analogue has no latency or display update rate- Analogue has no quantisation effects reducing the available resolutionIs there any modern digital scope that really addresses all these issues? At least for lower bandwidths I could imagine a continuos, triggerless data acquisition like in roll-mode. Display update rate is a matter of computing power and the relevance of quantisation is a matter of available memory - so very theoretically it may be possible, but did anyone do it?

author: MathWizard
author_rank: Super Contributor
timestamp: August 30, 2024, 03:38:13 am
content: Quote from: David Hess on March 22, 2018, 03:16:05 pmSo what could happen if you took some scope, and tried to get it working with a nice gaming PC. Surely if it's possible, someone with nothing better to do, has tried it.So with say a 1440p, 144Hz monitor, and some top of the line CPU and GPU ?? How good of an X-Y scope or regular scope could you make then ??What about years ago, when all CRT scopes had tiny screens, did people try to hack them together with nice big CRT TV's ??

author: Phil1977
author_rank: Frequent Contributor
timestamp: August 30, 2024, 04:23:16 am
content: Quote from: MathWizard on August 30, 2024, 03:38:13 amThis both doesn't work. You can't use a TV CRT for scope purpose and vice versa. Scope CRTs have electrostatic deflection, while TV CRTs have magnetic deflection. Both have their advantages/disadvantages and can mostly not be exchanged.Using a gaming PC? Yes, such a GPU is powerful but the system is everything but not almighty. A state of the art scope samples e.g. with 12bits and 2GS/s. A 12bit value is usually transferred as a 16bit value into a PC. That means we have 4GB/s (16bit = 2byte) per channel, meaning 8GB/s for two channels. We would at least need some specialized hardware that directly moves the data to the GPU memory. I´m not aware anything like that would exist.This data processing needs to be done in the FGPA of the scope (it has direct access to the samplers and to fast memory).

author: Someone
author_rank: Super Contributor
timestamp: August 30, 2024, 04:34:05 am
content: Quote from: MathWizard on August 30, 2024, 03:38:13 amOh dear, another one of those threads:https://www.eevblog.com/forum/testgear/oscilliscope-memory-type-and-why-so-small/?allThe video and audio world have fancy CRT emulating diagnostic displays including x-y traces. It's possible to do if there is a budget/demand for it. General purpose scopes have more important things to improve first.

author: David Hess
author_rank: Super Contributor
timestamp: August 30, 2024, 04:52:15 pm
content: Quote from: Phil1977 on August 29, 2024, 06:38:37 pmOld DSOs also work that way in XY mode.QuoteBandwidth has nothing to do with sample rate, especially in XY mode. One of the odder uses of those ancient Tektronix sampling mainframes was to produce an XY display with GHz of bandwidth, all at a sample rate of about 50 kS/s. With one exception, analog oscilloscopes otherwise have limited XY bandwidth because they have low horizontal bandwidth and the vertical delay line adds phase shift to the Y input. The one exception that I know of is the Tektronix 7104 because it has a high bandwidth vertical amplifier design for its horizontal deflection plates, achieving like 350 MHz on its X axis.But you bring up an interesting question. I just tested my 30 year old 2232 DSO, and in roll mode at slow sweep speeds, it generates its digital XY display continuously without any pause for triggering, just like the roll mode display is produced.