Author Topic: 350Mhz Scope, 2020  (Read 5758 times)

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Offline nctnico

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Re: 350Mhz Scope, 2020
« Reply #75 on: May 07, 2020, 10:29:20 pm »
I haven't heard about that, what are the justifications for the concerns?
First of all, the higher end R&S offerings (like RTO2K) feature an 8bit ADC and use digital filtering to offer "up to 16bit" with reduced sampling rate. So it seems strange that the entry level scopes should offer a true 10bit ADC while the much more expensive models don't. I recently stumbled over a LeCroy
I'm not quite sure whether this is a good assumption. The entry level models have 2.5Gs/s ADCs where the higher end ones have 20Gs/s. Also the RTB2k and RTM3k are general purpose oscilloscopes where the RTO2k and up are more geared towards dealing with high-speed signals. For a general purpose oscilloscope which is likely used to look at small signals having a 10 bit ADC can be an advantage. High speed signals OTOH need active probes so signal levels are far less of a problem.

Edit: I just did a test on the RTM3004. The smallest step I can get (using sample-hold mode display) is consistent with a 10 bit ADC.
« Last Edit: May 07, 2020, 10:59:40 pm by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 
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Offline 0xdeadbeef

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Re: 350Mhz Scope, 2020
« Reply #76 on: May 07, 2020, 10:58:06 pm »
Well, let's not focus on the RTO2K then. The RTE1K was presented around late 2017 or early 2018 AFAIK, so about at the same time as the RTB/RTM/RTA lines. Its price starts slightly above the RTA4K with similar technical specs. Still, as the RTO2K, it uses an 8bit ADC but provides up to 16bit with digital filtering. AFAIK the only other R&S model with than alleged 10bit ADC is the hand held "Scope Rider".
But anyway, as others stated before, even a good 10bit ADC doesn't provide much benefit in most situations. A 10bit ADC with the baseline noise performance of an 8bit ADC in most gain ranges doesn't seem like a major benefit.
But sorry, this has gotten pretty off-topic.
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Offline EEVblog

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Re: 350Mhz Scope, 2020
« Reply #77 on: May 07, 2020, 11:19:25 pm »
Well, this workflow (zooming out after a capture) is available on many DSOs. It is the standard (or at least configurable) on Tektronix, Rigol, GW Instek, R&S, the older Keysight scopes (DSO7000A / B series and derivatives), the original Siglent SDS2000 series and probably several others. However you have to realise that 'capture outside' the screen only works if there is memory left over after filling the screen. So it won't be the case at time/div settings where the maximum samplerate  is dropped. I have been using DSOs like this forever. I strongly recall being very annoyed by the Siglent SDS2000 not remembering this setting in the early firmware.

Sorry, I stand corrected, I had a brain fart, you are right. Both Rigol (2000) and (modern Megazoom IV) Keysight do this, they will capture full memory depth and allow you to "zoom out" from a shorter time base trigger capture.
Siglent (5000X) however does not do this, it captures the screen and that's it, you can't "zoom out" either in STOP mode or single shot triggered mode.
The Siglent sampling architecture must be implemented very differently.
Through habit I guess I've just learned not to rely on this when capturing.

Now I'm curious to see a list of scopes that do this and those that don't. But this should have it's own thread.
 

Offline EEVblog

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Re: 350Mhz Scope, 2020
« Reply #78 on: May 07, 2020, 11:23:03 pm »
But anyway, as others stated before, even a good 10bit ADC doesn't provide much benefit in most situations. A 10bit ADC with the baseline noise performance of an 8bit ADC in most gain ranges doesn't seem like a major benefit.

Sorry I don't agree. It's trivial to show examples where the 10 bit ADC in the R&S has advantages, I think I may have done this in one of my videos.
I won't argue that for most general uses it doesn't make a big difference, but it's really nice to have.
 
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Offline andrea.longobardi85

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Re: 350Mhz Scope, 2020
« Reply #79 on: May 08, 2020, 06:22:44 am »
Thank you all for your comments, I am inclined to go for the SDS5034X bundle, it doesn't seems the SDS2000X + has any advantages compared to the SDS5000X...
From your inputs the is seems R&S RTB2000, beside 10 bit ADC, doesn't have any significant advantage compared to the SDS5000x.
I do like the RTM3000 but it is out of budget I am afraid:) Thank you all!   
 
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Online tautech

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Re: 350Mhz Scope, 2020
« Reply #80 on: May 08, 2020, 07:30:31 am »
Thank you for sticking around.  ;)

Anyways, based on my use of SDS500X and SDS2000X+, do get yourself a cheap USB mouse to compliment the physical UI and touch display as it certainly opens up a further dimension when using these DSO's.

Is the current probe an urgent requirement or will you take a while to seek out what you need ?
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Offline andrea.longobardi85

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Re: 350Mhz Scope, 2020
« Reply #81 on: May 08, 2020, 08:06:54 am »
I Guess I can wait a bit, although will be nice to know have some option in mind in case suddenly needed.
Any suggestion for a current probe >2MHz?
 

Offline Wuerstchenhund

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Re: 350Mhz Scope, 2020
« Reply #82 on: May 08, 2020, 08:12:56 am »
Well, this workflow (zooming out after a capture) is available on many DSOs. It is the standard (or at least configurable) on Tektronix, Rigol, GW Instek, R&S, the older Keysight scopes (DSO7000A / B series and derivatives), the original Siglent SDS2000 series and probably several others. However you have to realise that 'capture outside' the screen only works if there is memory left over after filling the screen. So it won't be the case at time/div settings where the maximum samplerate  is dropped. I have been using DSOs like this forever. I strongly recall being very annoyed by the Siglent SDS2000 not remembering this setting in the early firmware.

Sorry, I stand corrected, I had a brain fart, you are right. Both Rigol (2000) and (modern Megazoom IV) Keysight do this, they will capture full memory depth and allow you to "zoom out" from a shorter time base trigger capture.
Siglent (5000X) however does not do this, it captures the screen and that's it, you can't "zoom out" either in STOP mode or single shot triggered mode.
The Siglent sampling architecture must be implemented very differently.

Indeed, it seems the Keysight InfiniVision scopes perform the last sample at full max memory independent on the timebase.

The Rigols seem to do it when memory is set manually (well, the memory management is pretty basic).

However, Keysight Infiniium scopes (at least for DSO8k and newer) don't.

LeCroy scopes don't, and as Siglent follows LeCroy their scopes don't, either.

Tek MDO3k & Co do through a trick (leaving the timebase longer and zooming in when selecting shorter ones), other ones don't (I can't remember so I have to rely on 3rd paty info here).

R&S I don't remember but I don't believe they do.

Quote
Through habit I guess I've just learned not to rely on this when capturing.

Now I'm curious to see a list of scopes that do this and those that don't. But this should have it's own thread.

Wouldn't this make a nice topic for one of your videos? Maybe coupled with a comparison of the nctnico method vs everyone else's method?  :-DD

I would watch that  :-+
 
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Offline Wuerstchenhund

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Re: 350Mhz Scope, 2020
« Reply #83 on: May 08, 2020, 08:17:26 am »
I Guess I can wait a bit, although will be nice to know have some option in mind in case suddenly needed.
Any suggestion for a current probe >2MHz?

Have a look at Hioki, they have various current probes and are also the OEM for many A brand probes:
https://www.hioki.com/en/products/list/?category=17

Based on your requirements (10A/10mA, >5MHz) the 3273-50 might be an option:
https://www.hioki.com/en/products/detail/?product_key=5717
 

Offline EEVblog

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Re: 350Mhz Scope, 2020
« Reply #84 on: May 08, 2020, 08:18:12 am »
Wouldn't this make a nice topic for one of your videos? Maybe coupled with a comparison of the nctnico method vs everyone else's method?  :-DD

What's his method again?, I must have missed that.
I just set the scopes max memory depth and a 1us timebase and STOP it. If it lets me zoom out to slower timebases and still show data then it passes.
Then repeat using a trigger signal just in case there is a difference between manual STOP mode and a trigger event capture.
 
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Online tautech

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Re: 350Mhz Scope, 2020
« Reply #85 on: May 08, 2020, 08:28:39 am »
I Guess I can wait a bit, although will be nice to know have some option in mind in case suddenly needed.
Any suggestion for a current probe >2MHz?
Some but there rise time is not good and current vs frequency derating not very good either.

Maybe if you can find the cheap Pintek PA-699 in the EU it might just do your work:
http://www.pintek.com.tw/
Not to be confused with Pintech that have copied many Pintek products.

Otherwise good current probes are like good scopes....they cost a lot..... but maybe Dave could indicate more specs of the one he's looking at selling and how far away it might be.
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Offline 2N3055

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Re: 350Mhz Scope, 2020
« Reply #86 on: May 08, 2020, 08:33:35 am »
There is Micsig CP2100B current probe that looks interesting.. It's rather new and there are not many reviews yet.
It seems OK. It's 2.5MHz AC/DC 10/100 A probe. Maybe you can give a call to Batterfly and arrange test....
It has very good price. I have Micsig High voltage probes and they are working very well. Good quality so far.
 
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Offline Wuerstchenhund

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Re: 350Mhz Scope, 2020
« Reply #87 on: May 08, 2020, 09:23:12 am »
Get this for $2000 (he will accept an offer for $2k) and hack it:

https://www.ebay.com/itm/Agilent-Keysight-DSOX3014T-100MHz-4Ch-5GS-s-Oscilloscope-with-N2890A-probes/383339365915

So your solution for a 350MHz scope which is for professional use is to spend $2k on a second hand 100MHz scope and then void any chance of warranty and manufacturer support by hacking it? Seriously?

Quote
The think is, that even if you buy the MSO5k, if you really want a Keysight or Tek, you will end up buying one of them as well.

Only if you're brand fixated. Which is quite common if you're a hobbyist.

If the scope becomes a tool that makes you money then price/performance and suitability for the tasks at hand count much more than brand image.
 

Offline maginnovision

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Re: 350Mhz Scope, 2020
« Reply #88 on: May 08, 2020, 05:48:39 pm »
In my case that's not true. If I pulled out initially to always see everything I'd spend more time calculating the timing measurements of the different signals than I would simply viewing the waveforms. Another issue I've run into is some scopes changing measurement resolution based on timebase in a way I lose the resolution I needed. I don't use $20k - $50k scopes though, I only need and use general purpose scopes. Maybe some more expensive scopes are better about that.
 
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Online jemangedeslolos

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Re: 350Mhz Scope, 2020
« Reply #89 on: May 08, 2020, 06:56:47 pm »
Which Picoscope model do you have 2N3055?
It seems interessting to investigate  ;)
 
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Online Gandalf_Sr

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Re: 350Mhz Scope, 2020
« Reply #90 on: May 08, 2020, 07:36:40 pm »
Is this the right forum for an argument?
If at first you don't succeed, get a bigger hammer
 

Offline Martin72

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Re: 350Mhz Scope, 2020
« Reply #91 on: May 08, 2020, 08:09:46 pm »
There is Micsig CP2100B current probe that looks interesting.. It's rather new and there are not many reviews yet.
It seems OK. It's 2.5MHz AC/DC 10/100 A probe. Maybe you can give a call to Batterfly and arrange test....
It has very good price. I have Micsig High voltage probes and they are working very well. Good quality so far.

It seems to be an interesting thing for it´s Price(Batronix).
Like (almost?) other probes, it´s accuracy decreases when measuring higher currents(40-100Apk, 15%...), but comparing to other probes, much expensive ones, it seems to be a real bang for bucks thing.
 
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Offline maginnovision

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Re: 350Mhz Scope, 2020
« Reply #92 on: May 08, 2020, 08:15:28 pm »
Yes the spec is conservative but the typical isn't bad. Once you start hitting those high currents you're probably comparing to known good waveform or estimating power where it's probably good enough. If you really wanted you could probably characterize it yourself for the frequencies you need if it were a critical measurement and the low cost was important or made you feel better.
 
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Offline nctnico

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Re: 350Mhz Scope, 2020
« Reply #93 on: May 08, 2020, 08:20:27 pm »
Is this the right forum for an argument?
For as long as people keep playing the ball and not the person there is no argument. Just an exchange of opinions and information.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 
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Offline Martin72

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Re: 350Mhz Scope, 2020
« Reply #94 on: May 08, 2020, 08:25:46 pm »
Yes the spec is conservative but the typical isn't bad.

Yepp, an interesting thing, makes me curious to compare it with our tek probes or lecroy ap011 at work and my owon cp05+ at home…

 
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Offline maginnovision

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Re: 350Mhz Scope, 2020
« Reply #95 on: May 08, 2020, 08:26:52 pm »
Yes the spec is conservative but the typhttps://jlcpcb.com/vical isn't bad.

Yepp, an interesting thing, makes me curious to compare it with our tek probes or lecroy ap011 at work and my owon cp05+ at home…

Sounds like fun!
 

Offline Martin72

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Re: 350Mhz Scope, 2020
« Reply #96 on: May 08, 2020, 08:33:51 pm »
Slightly OT, but one more time:

At work I´m used to using the lecroy ap011 current probe, because it´s so handy.
Someday I used this for measuring switching current from an Inverter.
The next day, I must change for some reasons to the tek A6303, a 100A/2Mhz probe.
The ap011 got 120khz bandwith…
Boy, what a difference concerning the visible waveforms...
 
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Offline 2N3055

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Re: 350Mhz Scope, 2020
« Reply #97 on: May 08, 2020, 08:45:45 pm »
Yes the spec is conservative but the typical isn't bad.

Yepp, an interesting thing, makes me curious to compare it with our tek probes or lecroy ap011 at work and my owon cp05+ at home…
Yes, please!!! ^-^
 

Offline Martin72

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Re: 350Mhz Scope, 2020
« Reply #98 on: May 08, 2020, 09:02:07 pm »
I´ll take the challenge, more to come in an separate thread, could last some weeks...
 
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Offline Someone

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Re: 350Mhz Scope, 2020
« Reply #99 on: May 09, 2020, 12:57:36 am »
So when nctnico says a scope can't do this very specific (and not fully explained) thing, just ignore it. Because with only a tiny change to any part of the application or acceptable solution, just about any scope will do the job.

Yeah, but he's not wrong.
It's an interesting and demonstrably potentially useful benefit.
But nctnico is wrong to generalise it as something other scopes can't do, because they can but in subtly different ways. Its a very narrow (and poorly/not defined) example to try and push some point like the marketing "comparisons" people keep laughing at.

The case of slow and infrequent triggers allows that type of use, and impedes/prevents acquisition of more rapid events (or they get lost in the long capture). Its a simple tradeoff (or "trap" as you might embellish it) that is chosen for the specific setting.

The inflammatory nature of this discussion has been the refusal of nctnico to acknowledge either the narrow applicability of the use case, or that it can be achieved by using a zoom window/view, or other methods.

Its a massive blow up over different methods to set the memory depth (auto vs manual vs implicit vs explicit).
 


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