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| Why do you think there aren't more "good" USB oscilloscopes? |
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| 2N3055:
--- Quote from: james_s on February 17, 2023, 04:27:46 am ---Well there are niche uses like yours, but I don't think most scope users are in that situation. Personally I find a compact standalone scope more convenient. --- End quote --- It really depends what you do. If you only repair stuff, never develop new things that require lots of documentation, never do post analysis of data etc, then a standalone scope is simplest thing to use, sure. Switch on, poke around with probe looking at the screen, fix this and that, try again and done... LeCroy and Keysight have a PC application that you run on your PC that is version of scope application from their PC based scopes for that same purpose.. Maybe not a mainstream use, but definitely not such a niche... When you have a scope application open on your PC together with editor, Octave, some datasheets etc and can copy, paste, save etc at the same time without any problems, it helps a lot. And, also, if you do the post analysis, data transfer rates are MUCH faster from a propper USB scope than any of the SCPI combinations I ever tried... |
| 2N3055:
--- Quote from: David Hess on February 17, 2023, 08:48:42 am --- --- Quote from: Gyro on February 16, 2023, 06:03:22 pm ---The cheap screens on desktop scopes is something that I still don't get. They seem to have poor resoulutions compared to what you can get out of a tablet screen for instance. Even at 2 channels, with all the menu and readout stuff around the edges you're lucky to get 6 bit resolution on a 2 channel scope, let alone a 4 channel. Is it just cheaping out or lack of processing power? --- End quote --- It could be, especially since producing the display for a higher resolution and depth screen would lower the peak number of acquisitions per second. Which sounds better for marketing, 40,000 acquisitions per second or 10,000 with a higher definition screen that looks practically the same? --- End quote --- This.. Once you go over certain DPI, there is no benefit to visibility but a huge problem with much more processing.... |
| David Aurora:
--- Quote from: EEVblog on February 17, 2023, 08:01:42 am --- --- Quote from: David Aurora on February 17, 2023, 03:58:43 am --- --- Quote from: james_s on February 17, 2023, 03:48:25 am ---USB scopes are a really niche market item. The computer side with the display and whatnot is so cheap these days that there is very little saved in going with the USB form factor that requires you to drag around a computer and deal with cumbersome controls. For around the same price you can get a standalone instrument. I've used USB TE before and have never been impressed, it's less convenient and offers few advantages. Back in the day the promise was cheaper gear by not having to duplicate the processor and display and such but it never really lived up to that promise IMO. --- End quote --- Speaking for myself, it's not that I'm trying to save a few measly dollars on the screen or power supply or whatever. It's that when I'm called out to a job I already have my laptop with me with a nice big screen and the necessary processing power to run a scope/sig gen/etc, as well as a few bags of tools and test leads and stuff. Carrying less gear helps, especially when parking sucks, there are a million stairs or it's a dodgy area. And it's not just that it saves lugging one scope- it also saves me needing to lug a signal generator, and also an isolation transformer in some cases. Which also means I don't need a power board, extension cables, etc... It all adds up. --- End quote --- Small tablet scope? Not a huge amount bigger than a USB scope box and more convenient. The problem is as others have said, the market for such things is not big. It seems to be either ultra-cheap (Hantek/Owon etc), educational (Analog Discovery), niche like Cleverscope, or pro level modular stuff like Keysigt and others do. Or even the Scopemeter type devices. You seen to want say a screenless scope equivlent to say a $400 Rigol/Siglent type scope. What's wrong with a Picoscope, isn't that what you want? --- End quote --- Yeah but again, the point is not lugging yet another bit of gear when there's already a laptop with me. The tablet thing is weird because yeah, they're small, but they also aren't going to have the same capabilities as a USB one, so it becomes another game of what else you need to bring to round things out. I've definitely considered it though, and may still get one at some point. That said, I've already got a DSO that's probably not much bigger than a tablet scope if we're gonna play the "not much bigger than..." game, but then we're back to square one with a signal generator and isolation transformer and so on. Going for super high end doesn't make sense in my case either because I have real gear at the workshop- for me (and likely others) it's more about having an electronics Swiss army knife. I literally always carry a Leatherman for day to day quick fixes, this is like that. I just want something with enough basic tools to get me out of a jam on site, if deeper analysis is required then I can take repairs back to work or come in with more gear and parts. A good example of how this works for me would be a job a few weeks ago- a large format (as in it needs to be moved in pieces by truck) mixing console installation/restoration in a studio. The deep repairs get done back at the shop, but having the AD2 and laptop with me was perfect for sweeping through the patchbay checking for signals, tracing bad connections, verifying operation of individual sections and so on. I could easily switch windows to update my notes, check the schematic, save reference waveforms for channel comparisons and even play music for listening tests, all from the one place. The catch of course being the horrendous probe adaptor (although I literally just made myself a better one today that plugs straight in and gets rid of the short risk, plus compensates better) The sell with the stuff like Picoscopes is that I could literally throw it and a pair of probes in my existing laptop case with the laptop and I'm set. It's fantastic in theory and DOES fill this gap... in theory. In practice, when I tried one the software was fucking atrocious and completely unusable for real work and got sent back immediately. But as I mentioned earlier in this thread, I'm told they've shipped a loaner out to me to try out the new, finished version 7 software so my fingers and toes are crossed that it delivers. If it does, great, I'll buy one. If it doesn't I'll resume wishing for Diligent to release something that fits the bill, because for me their software is perfect. |
| PlainName:
--- Quote from: David Hess on February 17, 2023, 08:48:42 am --- --- Quote from: Gyro on February 16, 2023, 06:03:22 pm ---The cheap screens on desktop scopes is something that I still don't get. They seem to have poor resoulutions compared to what you can get out of a tablet screen for instance. Even at 2 channels, with all the menu and readout stuff around the edges you're lucky to get 6 bit resolution on a 2 channel scope, let alone a 4 channel. Is it just cheaping out or lack of processing power? --- End quote --- It could be, especially since producing the display for a higher resolution and depth screen would lower the peak number of acquisitions per second. Which sounds better for marketing, 40,000 acquisitions per second or 10,000 with a higher definition screen that looks practically the same? --- End quote --- Are you sure? There is no way a display is updating at 40,000Hz. And if it did you wouldn't notice any difference between that and 10,000Hz. The display is surely decoupled from the acquisition and merely shows a snapshot of the acquisition buffer every screen update (at 30~120Hz). A larger screen may well require more CPU oomph but will that be taken from the waveform capture hardware? Don't they use DMA anymore? Are we, perhaps, being confused and misled by these numbers? |
| peter-h:
--- Quote ---LeCroy and Keysight have a PC application that you run on your PC that is version of scope application from their PC based scopes for that same purpose.. --- End quote --- Those apps are very slow. You are looking at update rates like 1 second - even over 100mbps/1gps ethernet. Poorly written? Sure! Look pretty though and handy for screenshots for posting on EEVBLOG ;) |
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