Author Topic: Why do you think there aren't more "good" USB oscilloscopes?  (Read 8820 times)

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Online 2N3055

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #50 on: February 17, 2023, 08:49:14 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.

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...
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Online 2N3055

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #51 on: February 17, 2023, 08:51:06 am »
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?

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?

This..

Once you go over certain DPI, there is no benefit to visibility but a huge problem with much more processing....
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Online David Aurora

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #52 on: February 17, 2023, 09:05:51 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.

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.

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?

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.
 

Online PlainName

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #53 on: February 17, 2023, 10:13:25 am »
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?

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?

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?
 

Online peter-h

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #54 on: February 17, 2023, 11:05:23 am »
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..

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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Offline TomKattTopic starter

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #55 on: February 17, 2023, 11:15:30 am »
The fastest USB3 links aren't even remotely close to matching the internal data transfer rates in an oscilloscope.  You can remote the display and control interface, but if you offload the actual captures to the PC for processing, it won't happen as quickly.  This is a limitation of PicoScopes, although not a problem in most cases.  You simply can't dump data at the full capture rate to the PC memory, you have to make a capture and then wait for it to be transmitted.
I agree the triggering and processing has to be done at the hardware level.  I guess what I'm thinking of is more the ability to manipulate the captured information, whether that be longer signal time analysis or improving the MSO LA capabilities by going beyond analysis of what is stored on a single screen capture.

I see now that the 'computer side' of stand alone devices (screen etc) are likely commodity items and there is likely not much of an economic advantage to eliminating those elements and using laptop gear instead.

So, it all comes down to mobility and additional analysis I guess.  To that end, a tablet-like more pc oriented device would serve equally well...  It wouldn't necessarily need to be USB / laptop.  So it becomes more of a niche market product, explaining why I guess there aren't more 'good' ones.
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Online Nominal Animal

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #56 on: February 17, 2023, 11:16:26 am »
There is no way a display is updating at 40,000Hz.
It doesn't have to.  Each display frame contains the acquisitions –– to simplify, one curve per acquisition –– since the last display update.

At 75 Hz update rate, 40k acquisitions per second would be about 533 acquisitions per frame, or 533 curves of the sampled data per frame.
At 10k acquisitions per second, it'd be 133 curves of the sampled data per frame.  Is that visible?  I dunno, not enough practical experience to say.

Those apps are very slow.
It is extremely difficult to make good products that cross niches.  Here, the problem is that as a product, you need software running on arbitrary random machines efficiently, and you need hardware that interfaces nicely with random machines, and you need the combination to work well.

You essentially need a good hardware team that can provide the sampled data to a well-defined (in advance) interface (USB or Ethernet using TCP or UDP stack), and a software team that is more oriented towards games than typical commercial office programs.

To make the combination work well, you need management that can interact effectively with both teams.  Do you have any idea how rare such management is?

The standard commercial solution (not talking about USB scopes only here, but more generally any similar appliance) seems to be that either one part is bought from a different company, or the software is made by the equivalent of a bunch of high-schoolers; regardless of what the appliance is.
 

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #57 on: February 17, 2023, 11:22:12 am »
There is no way a display is updating at 40,000Hz.
It doesn't have to.  Each display frame contains the acquisitions –– to simplify, one curve per acquisition –– since the last display update.

At 75 Hz update rate, 40k acquisitions per second would be about 533 acquisitions per frame, or 533 curves of the sampled data per frame.
At 10k acquisitions per second, it'd be 133 curves of the sampled data per frame.  Is that visible?  I dunno, not enough practical experience to say.

Well, quite. The display rate shouldn't affect the acquisition rate, so having a bigger screen shouldn't mean a reduction of captures from, for instance, 40k/s to 10k/s. Which was the point.
 
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Online 2N3055

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #58 on: February 17, 2023, 12:09:10 pm »
There is no way a display is updating at 40,000Hz.
It doesn't have to.  Each display frame contains the acquisitions –– to simplify, one curve per acquisition –– since the last display update.

At 75 Hz update rate, 40k acquisitions per second would be about 533 acquisitions per frame, or 533 curves of the sampled data per frame.
At 10k acquisitions per second, it'd be 133 curves of the sampled data per frame.  Is that visible?  I dunno, not enough practical experience to say.

Well, quite. The display rate shouldn't affect the acquisition rate, so having a bigger screen shouldn't mean a reduction of captures from, for instance, 40k/s to 10k/s. Which was the point.

Point is that screen with 2x resolution has 4x of pixels and that display engine has to crunch 4x more data for same result.
Which means 4x more capable infrastructure for that. Not impossible but not free...
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Online Nominal Animal

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #59 on: February 17, 2023, 12:18:29 pm »
The display rate shouldn't affect the acquisition rate, so having a bigger screen shouldn't mean a reduction of captures from, for instance, 40k/s to 10k/s. Which was the point.
Oops.  I missed the point, as usual.  Sorry :-[

I can understand the reduction of captures if each capture sequence is at most as long as is shown on the screen, but otherwise I'd expect the captured signal (and the acquisition buffer) be wider than the screen.

That leads to an interesting question: Should an USB scope always provide the sample sequences, or would it be better if it sometimes returned the combined acquisition buffer instead?

There are many forms such a buffer could take, but the simplest form I can think of has 256 8-bit bins per time unit, forming a 256-bin histogram of the acquired curves at that point in time relative to the trigger.  The computer could request updates only on a specific section (a screenful), and when paused, request the entire buffer (up to whatever time depth is available), or the data from the latest acquisition.  (That assumes an 8-bit ADC, by the way.  For an N-bit ADC, I'd expect 2N samples per time unit.)

Typical data rate could be for example 1920 time units 25 times each second, i.e. 12,288,000 bytes per second.

More generally, given W time units, F times per second, N-bit ADC, we have W×F×2N bytes per second at 8-bit bins (up to 255×F acquisitions per second), and 2×W×F×2N bytes per second for 16-bit bins (up to 65535×F acquisitions per second).

While one might think that this contains the display information, it is actually just the histogram of the acquisitions; i.e. full information (except order of acquisitions), time-wise limited to W time units relative to trigger point.  It's also quite feasible to implement on any hardware that has the memory bandwidth to store both the latest acquisition and access one entry of the 2N-byte or -word histogram for that time point.  Maximum sample depth or W does not affect the work needed to be done, assuming double buffering, except for the zeroing of the memory after it has been sent (to prepare for it to be useable as the histogram buffer).
 

Online PlainName

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #60 on: February 17, 2023, 12:29:52 pm »
Quote
Should an USB scope always provide the sample sequences, or would it be better if it sometimes returned the combined acquisition buffer instead?

It would be nice if one had the choice :)

Much of the time, a snapshot of the acquisition buffer every display update would be fine - we often want a real-time display as we're poking at things and setting up. But sometimes you want a looong capture you can scroll through at your leisure, and the USB scope scores there because it has the entire PC storage resource to play with.
 

Offline jasonRF

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #61 on: February 17, 2023, 01:42:03 pm »
So why do you think there aren't more USB scopes on the market?

current offerings satisfy demand
This.  Most professional users want a bench scope (I have never seen a USB scope at work), and when a USB scope is in order there are already enough 'good' options available.  There is a pretty big barrier to entry in this market: need to have good hardware, good software, and to chip business away from Picotech need to have either a significantly lower price or some better specs or additional features that people care about. 

There are companies that are trying to do this, for example TiePie
https://www.tiepie.com/en/usb-oscilloscope/handyscope-hs6
but if you are going to spend that much, do you go with the 'unknown' brand or just go with Pico?  Keysight offers a couple of models but they have weird limitations (eg the 1250 point FFT size).  They also fit into Keysight card-cages alongside other instruments to make self-contained systems, and I suspect that is what they are really designed for. 

For the hobby market
- snip -
people expect cheap, which is what the chinese ones deliver. But cheap means you don't have any money left for a decent software development team.
Look at the Digilent Analog Discovery 2 for example, there is basically nothing in the hardware yet it's US$400, the same price as a great and vastly more capable in many respects 4CH USB bench scope. Why? Because the software and support is awesome and you pay a premium for that.
- snip -
is exactly right.  Some of the 'cheap' scopes have good-enough hardware.  But the software keeps them far away from being a 'good' scope.  The Owon vds6102a multi-resolution scope is a prime example.   Some of the cheap scopes are a mediocre mixed-bag for hardware and software - the DreamSourceLab scopes are examples: only 10 mV/div sensitivity, fast updates on USB3 models, software that actually works well but has almost no features beyond the basics. 

Some scopes might have okay software, but have some weird hardware issues.  Virtins comes to mind, and while I have never used their Multi-Instrument software, it looks feature-rich.  The issue is the hardware.  Sample-rates are only 2.5 times the bandwidth with a single channel running, so with 2 channels running you only have 1.25x sampling.  Likewise, only 40 kSample memory.  But they have some nice-looking signal generators built-in that can also stream, which could be interesting for lower-frequency work.  If I saw one for a good price on ebay I would probably pick it up for funsies just for the streaming waveform generator. 

When I was looking to get a 'nice' USB scope for hobby use last year I quickly realized that Pico was the only game in town.  Since I did not have that large of a budget I just patiently waited for a good deal on ebay and got lucky on a used 5244B.  This approach only worked because I did not need more than 2 channels;  it is very rare to see large discounts on 4-channel scopes. 

jason
« Last Edit: February 17, 2023, 01:45:16 pm by jasonRF »
 

Online 2N3055

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #62 on: February 17, 2023, 01:48:41 pm »
So why do you think there aren't more USB scopes on the market?

current offerings satisfy demand
This.  Most professional users want a bench scope (I have never seen a USB scope at work), and when a USB scope is in order there are already enough 'good' options available.  There is a pretty big barrier to entry in this market: need to have good hardware, good software, and to chip business away from Picotech need to have either a significantly lower price or some better specs or additional features that people care about. 

There are companies that are trying to do this, for example TiePie
https://www.tiepie.com/en/usb-oscilloscope/handyscope-hs6
but if you are going to spend that much, do you go with the 'unknown' brand or just go with Pico?  Keysight offers a couple of models but they have weird limitations (eg the 1250 point FFT size).  They also fit into Keysight card-cages alongside other instruments to make self-contained systems, and I suspect that is what they are really designed for. 

For the hobby market
- snip -
people expect cheap, which is what the chinese ones deliver. But cheap means you don't have any money left for a decent software development team.
Look at the Digilent Analog Discovery 2 for example, there is basically nothing in the hardware yet it's US$400, the same price as a great and vastly more capable in many respects 4CH USB bench scope. Why? Because the software and support is awesome and you pay a premium for that.
- snip -
is exactly right.  Some of the 'cheap' scopes have good-enough hardware.  But the software keeps them far away from being a 'good' scope.  The Owon vds6102a multi-resolution scope is a prime example.   Some of the cheap scopes are a mediocre mixed-bag for hardware and software - the DreamSourceLab scopes are examples: only 10 mV/div sensitivity, fast updates on USB3 models, software that actually works well but has almost no features beyond the basics. 

Some scopes might have okay software, but have some weird hardware issues.  Virtins comes to mind, and while I have never used their Multi-Instrument software, it looks feature-rich.  The issue is the hardware.  Sample-rates are only 2.5 times the bandwidth with a single channel running, so with 2 channels running you only have 1.25x sampling.  Likewise, only 40 kSample memory.  But they have some nice-looking signal generators built-in that can also stream, which could be interesting for lower-frequency work.  If I saw one for a good price on ebay I would probably pick it up for funsies just for the streaming waveform generator. 

When I was looking to get a 'nice' USB scope for hobby use last year I quickly realized that Pico was the only game in town.  Since I did not have that large of a budget I just patiently waited for a good deal on ebay and got lucky on a used 5244B.  This approach only worked because I did not need more than 2 channels;  it is very rare to see large discounts on 4-channel scopes. 

jason

I assure you predominant number of Picoscopes is sold to companies...
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Offline jasonRF

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #63 on: February 17, 2023, 03:15:53 pm »

I assure you predominant number of Picoscopes is sold to companies...
I believe it.  And I would be shocked if they did not dominate that market.  My writing can be meandering, but in the first part of my post I was trying to say that we probably don’t have a lot more ‘good’ usb scopes because Pico has cornered the market for the most part.  It would take a lot of up-front investment for another company to challenge them.  The big players like Tek/Keysight/etc must believe that there just in’t enough money to be made in that market. 

Jason
 
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Offline hans

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #64 on: February 17, 2023, 04:05:55 pm »
I personally think the reason an USB scopes are not very popular, is  similar to how many other TE doesn't use GUI's that only operate on PCs. Most people want buttons and don't mess around with desktop software. You boot it up and it always is up in 1min, anyone can use it, etc.

I don't think it's the problem that laptops are going out of fashion. In university we sometimes have people showing up with iPad Pro's to C programming classes in 1st year CS/EE. "Because it's a capable piece of kit right?"... yes the iPad Pro with M1 is very fast.. but it runs a crippled OS and is not made for power users. As staff we have to inform them politely they didn't got the right equipment. There is a reason many universities give 'strong recommendations'  or even 'requirements' for which laptops to use. In my old school from 2008 era we still had school machines, but they went out of fashion and nobody used them. I don't see these anymore, except for in the library, I think...

As @EEVBlog suggested, HDMI outputs can help with the small displays, But for reasons I state before, the PC connectivity can be very important. Namely; a scope has quite a neat seat of hardware under FPGA control (ADCs, DACs) which could also be used in 'rolling' timebase more (a ADC/DAC stream). People pay tons of money to have A/D and D/A boxes for radio equipment.
In essence an USB scope doesn't have to be simpler than a desktop scope. But it seems to be a common design goal, I agree.
 The main challenge is to transmit waveform data over a cable. The FPGA in the scope can do all the triggering, acquisition, segmenting, etc. Then on a desktop screen, it could be rendered and analyzed with far more processing power.. For automation, which I'm all for in a modern lab, this can be a bliss. If you just want to probe around, give me knobs.

But let's say a scope is trying to reach 1M wfm/s at 120pts per waveform. Then that's 120MS/s to transmit over USB, with some framing associated. Even if those samples are >8-bit (e.g. hi-res ADC or hi-res oversampling etc.), then that's about 240MB/s of data to transfer. Modern USB standards can easily cope with this. You could even higher waveform pts to accommodate larger displays or sampling fidelity.
Problem is that this kind of custom protocol and implementation is not simple.. and the PC needs to have some grunt as well to do the phosphor drawing outside of FPGA/ASIC fabric.
« Last Edit: February 17, 2023, 04:08:12 pm by hans »
 

Offline Infraviolet

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #65 on: February 17, 2023, 08:15:07 pm »
David Aurora, I know that picoscope USB oscilloscope software is available as a linux version.

As for why not more high quality ones made,  perhaps it is a mattter of the analog parts of the scope being the priciest, and so all the computer stuff built in to modrn scopes is cheap by comparison. To make a profit they might have to still sell a USB scope for just as much as a full scope, and that might well put off a lot of buyers?
 

Online nctnico

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #66 on: February 17, 2023, 09:07:13 pm »
So why do you think there aren't more USB scopes on the market?

current offerings satisfy demand
This.  Most professional users want a bench scope (I have never seen a USB scope at work), and when a USB scope is in order there are already enough 'good' options available.  There is a pretty big barrier to entry in this market: need to have good hardware, good software, and to chip business away from Picotech need to have either a significantly lower price or some better specs or additional features that people care about. 

There are companies that are trying to do this, for example TiePie
https://www.tiepie.com/en/usb-oscilloscope/handyscope-hs6
but if you are going to spend that much, do you go with the 'unknown' brand or just go with Pico?
Well, TiePie has been around for at least 3 decades. So this isn't some kind of unknown new brand. To be honest, I'm surprised they are still around; in my mind I was thinking they are somehow relatted to Picoscope but it seems they are not. Anyway, I have used one of their earlier devices a very, very long time ago. At least 30 years ago.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline Kasper

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #67 on: February 17, 2023, 09:24:51 pm »
I used Picoscope years ago and really liked it.
 

Offline jasonRF

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #68 on: February 17, 2023, 09:57:05 pm »
So why do you think there aren't more USB scopes on the market?

current offerings satisfy demand
This.  Most professional users want a bench scope (I have never seen a USB scope at work), and when a USB scope is in order there are already enough 'good' options available.  There is a pretty big barrier to entry in this market: need to have good hardware, good software, and to chip business away from Picotech need to have either a significantly lower price or some better specs or additional features that people care about. 

There are companies that are trying to do this, for example TiePie
https://www.tiepie.com/en/usb-oscilloscope/handyscope-hs6
but if you are going to spend that much, do you go with the 'unknown' brand or just go with Pico?
Well, TiePie has been around for at least 3 decades. So this isn't some kind of unknown new brand. To be honest, I'm surprised they are still around; in my mind I was thinking they are somehow relatted to Picoscope but it seems they are not. Anyway, I have used one of their earlier devices a very, very long time ago. At least 30 years ago.
I obviously had no idea they have been around that long.   I see that they only have one US distributor, and it is not exactly a well-known vendor.  That may be why they were unknown to me until i was in the market last year.   

Jason
 

Online David Hess

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #69 on: February 17, 2023, 09:58:57 pm »
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.

As others pointed out before my reply, the display is a histogram produced from multiple acquisitions.

Although I wonder now whether the size of the display record has any effect on the processing required since every sample is processed once no matter what the size of the display record is.  It could matter if the acquisition record is decimated because of lack of processing power.
 

Online David Aurora

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #70 on: February 17, 2023, 11:30:44 pm »
David Aurora, I know that picoscope USB oscilloscope software is available as a linux version.

As for why not more high quality ones made,  perhaps it is a mattter of the analog parts of the scope being the priciest, and so all the computer stuff built in to modrn scopes is cheap by comparison. To make a profit they might have to still sell a USB scope for just as much as a full scope, and that might well put off a lot of buyers?

I'm not on Linux, so  :-//

Likely Linux users have had the same issues as Mac users though in that they claimed it worked on that platform, but when you actually buy it and plug it in you find out the old version doesn't work anymore and the new version was beta with half the features you need missing/broken. The stable release of 7 just dropped in the past few weeks though so that may no longer be an issue, I'll find out when my test device arrives.

As for the other point, I don't think a USB variant needs to be cheaper than the standalone version. You can get full DSOs for less than many Picoscope models, I don't think people look at them as the cheaper option. It's not about price, it's about convenience/portability/extended functionality in software. Which, if done well, creates its own value. Another example being what Dave said earlier in the thread, Analog Discovery 2 boxes absolutely aren't worth their price for the hardware, the value is in the software.

I get that I'm in the minority of people who want a USB scope, but I think part of the unpopularity of them is the clear misunderstanding you see in threads like this about where they fit in the grand scheme of things. I doubt anyone with a clue about electronics is looking for a USB scope to be their primary scope, or expecting one for $100, or wishing they had real knobs, or whatever. They supplement real test gear rather than replace it.

My current life is a tech fixing audio gear and my previous life was as a recording engineer/producer, and in this world I've seen these exact same arguments hashed out for decades now with the same misunderstanding. Does a $500 USB audio interface replace a million dollar recording facility? Absolutely not. Is it the best tool for the job when you're fucked for time and need to edit drums on a plane between sessions? 100%.
 

Online EEVblog

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #71 on: February 18, 2023, 06:03:37 am »
My current life is a tech fixing audio gear and my previous life was as a recording engineer/producer, and in this world I've seen these exact same arguments hashed out for decades now with the same misunderstanding. Does a $500 USB audio interface replace a million dollar recording facility? Absolutely not. Is it the best tool for the job when you're fucked for time and need to edit drums on a plane between sessions? 100%.

I have a top of the range National Instruments USB scope, yet I would greatly pefere to use a bottom of the range Rigol/Siglent on the bench because of the convenience.
And there is somethign about having a scope right next to your work on the bench so you don't have the glance up at monitor. Same argument for handheld vs bench multimeter for bench use, handheld wins almost every time, you can bring the meter right physically close to the work.
 

Offline JPortici

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #72 on: February 18, 2023, 06:06:25 am »
David Aurora, I know that picoscope USB oscilloscope software is available as a linux version.

As for why not more high quality ones made,  perhaps it is a mattter of the analog parts of the scope being the priciest, and so all the computer stuff built in to modrn scopes is cheap by comparison. To make a profit they might have to still sell a USB scope for just as much as a full scope, and that might well put off a lot of buyers?

I'm not on Linux, so  :-//

Likely Linux users have had the same issues as Mac users though in that they claimed it worked on that platform, but when you actually buy it and plug it in you find out the old version doesn't work anymore and the new version was beta with half the features you need missing/broken. The stable release of 7 just dropped in the past few weeks though so that may no longer be an issue, I'll find out when my test device arrives.

As for the other point, I don't think a USB variant needs to be cheaper than the standalone version. You can get full DSOs for less than many Picoscope models, I don't think people look at them as the cheaper option. It's not about price, it's about convenience/portability/extended functionality in software. Which, if done well, creates its own value. Another example being what Dave said earlier in the thread, Analog Discovery 2 boxes absolutely aren't worth their price for the hardware, the value is in the software.

I get that I'm in the minority of people who want a USB scope, but I think part of the unpopularity of them is the clear misunderstanding you see in threads like this about where they fit in the grand scheme of things. I doubt anyone with a clue about electronics is looking for a USB scope to be their primary scope, or expecting one for $100, or wishing they had real knobs, or whatever. They supplement real test gear rather than replace it.

My current life is a tech fixing audio gear and my previous life was as a recording engineer/producer, and in this world I've seen these exact same arguments hashed out for decades now with the same misunderstanding. Does a $500 USB audio interface replace a million dollar recording facility? Absolutely not. Is it the best tool for the job when you're fucked for time and need to edit drums on a plane between sessions? 100%.

However to get a dso as powerful as the pico you have to drop big money over the DSO that costs the same.
Wfm/s are way less important than what the average person things, there are analog scopes or keysights if you care about wfm/s, what's important is what you can do with the computer at your disposal: as many* decoders as you want, plus the capability of creating your own. As many* math traces, math with formula, plotting math, math on math, multiple views at the same time (spectrum, persistence, actual data)

*there is probably an actual limit, i haven't reached it yet.

What picoscopes lack is the capability to trigger on anything different than an edge (it does edge, pulse, sequence of edges,  runt?) especially decoders or triggering on math traces, as they are all calcuated on the PC side after the acquisition. That's fine as they cost 10x less than DSOs that do that*

*not the four bog standard decoders of course, all the exotic ones and the custom ones

Me, when i'm using the pico i'm usually with my laptop and other equipment, all running on USB, inside a car or simillar environments, on the go. I don't have access to power outlets, i don't have space for more than one screen. USB instruments are what i need for convenience. On the bench depending on what i have to probe, it's either dso or pico, usually pico as it's one click away from starting and probing is already done, but dso if i have to probe around
« Last Edit: February 18, 2023, 06:09:04 am by JPortici »
 

Offline EPAIII

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #73 on: February 18, 2023, 07:06:29 am »
I fail to see how the desirability and capability of the two types of scope are related.

There is no reason in the world why a high capability scope can not be made in a form factor that no one wants.
Paul A.  -   SE Texas
And if you look REAL close at an analog signal,
You will find that it has discrete steps.
 

Online 2N3055

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Re: Why do you think there aren't more "good" USB oscilloscopes?
« Reply #74 on: February 18, 2023, 09:15:46 am »
My current life is a tech fixing audio gear and my previous life was as a recording engineer/producer, and in this world I've seen these exact same arguments hashed out for decades now with the same misunderstanding. Does a $500 USB audio interface replace a million dollar recording facility? Absolutely not. Is it the best tool for the job when you're fucked for time and need to edit drums on a plane between sessions? 100%.

I have a top of the range National Instruments USB scope, yet I would greatly pefere to use a bottom of the range Rigol/Siglent on the bench because of the convenience.
And there is somethign about having a scope right next to your work on the bench so you don't have the glance up at monitor. Same argument for handheld vs bench multimeter for bench use, handheld wins almost every time, you can bring the meter right physically close to the work.

Like I said before. It really depends on what you do. For repair type of work physical standalone scopes are good choice.
My son did a lot of assignments for uni using Pico because there you have to document what you do. I do a lot of development using Picos, because, you guessed it, I need to document what I do.
Also like JPortici said (him and I are example of people that do work that Picos are good for), there are many things you can do with them no other scopes can. It decodes twice the number of protocols than my fully unlocked MSOX3104T.
You can define your own probes and can connect sensors, linearize them and convert a value to true physical property. For instance, connect NTC circuit and show temperature on screen. On X-Y  plot where other value is power from math channel that came from two other sensors... OR X-Y plot of 7 other values on same plot...
OR...
Picoscopes are analytic scopes. Cheapest ones you can buy. You need to go with higher end LeCroy with additional advanced math packages to get something better.. And even then Pico has some functions no other scope has.

They are great because they are different, so they can do different things. I'm always amazed when people buy 8 scopes that are all basically the same functionality...
"Just hard work is not enough - it must be applied sensibly."
Dr. Richard W. Hamming
 
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