Author Topic: Most (Digital-)Scopes are freezing while vertical adjustement...  (Read 4877 times)

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Online Martin72Topic starter

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Most (Digital-)Scopes are freezing while vertical adjustement...
« on: November 14, 2022, 10:15:55 pm »
Hi,

To keep the BUG thread of the new rigol HD scope free from it, and because I think it´s a thing of general interest, here a dedicated thread for it.
The beginning:

https://www.eevblog.com/forum/testgear/new-rigol-hdo1000-12-bit-dso-bugs/msg4519475/#msg4519475

And most of the following posts there...
So what do you think, when scope´s freezes while adjusting vertical line, is it a bug most scopes then got ?
Keysight are mentioned not to do this, also GWInstek - Not all models.
Carry on here...

Martin
« Last Edit: November 15, 2022, 12:20:01 am by Martin72 »
 

Online nctnico

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Re: Most (Digital-)Scope are freezing while vertical adjustement...
« Reply #1 on: November 14, 2022, 10:24:29 pm »
R&S doesn't freeze either
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 
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Online 2N3055

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Re: Most (Digital-)Scope are freezing while vertical adjustement...
« Reply #2 on: November 14, 2022, 10:27:41 pm »
No it is not a bug. It is how its made and fine. There is no practical reason for that. You look at the screen, you decide you will move waveform, you start moving, scope stops and shows you last captured squiggle as a visual aid, you set it and let go of the button. Scope resumes...
Only problem is if scope waits a lot of time to resume capture after you let go...

Keysight 2000, 3000A and 3000T (and 4000B probably, they are a fancy 3000T) stop while vertical moving, but resume so fast people think they update while moving if you move it slow enough...
"Just hard work is not enough - it must be applied sensibly."
Dr. Richard W. Hamming
 
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Offline skander36

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Re: Most (Digital-)Scope are freezing while vertical adjustement...
« Reply #3 on: November 14, 2022, 10:28:57 pm »
Keysight2k and R&S RTB2k stops updating when adjusting vertical position.
 

Online Martin72Topic starter

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Re: Most (Digital-)Scope are freezing while vertical adjustement...
« Reply #4 on: November 14, 2022, 10:34:09 pm »
Quote
You look at the screen, you decide you will move waveform, you start moving, scope stops and shows you last captured squiggle as a visual aid, you set it and let go of the button.

This is excactly what I think about it.
When examining a say 3-phase sinewave signal, I´ll put them on the screen in a order that fits best to see and while I´m doing this, it doesn´t matter, if the signals will be frozen in this time...

Online 2N3055

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Re: Most (Digital-)Scope are freezing while vertical adjustement...
« Reply #5 on: November 14, 2022, 10:47:58 pm »
R&S doesn't freeze either

I know you have that scope, but are you sure?.
I believe it behaves same as MSOX3000T, it stops while moving but resumes immediately.
"Just hard work is not enough - it must be applied sensibly."
Dr. Richard W. Hamming
 

Online nctnico

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Re: Most (Digital-)Scope are freezing while vertical adjustement...
« Reply #6 on: November 14, 2022, 10:51:31 pm »
Quote
You look at the screen, you decide you will move waveform, you start moving, scope stops and shows you last captured squiggle as a visual aid, you set it and let go of the button.

This is excactly what I think about it.
When examining a say 3-phase sinewave signal, I´ll put them on the screen in a order that fits best to see and while I´m doing this, it doesn´t matter, if the signals will be frozen in this time...
Doesn't work if the signal is varying wildly and you want it on screen fully.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Online Martin72Topic starter

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Re: Most (Digital-)Scope are freezing while vertical adjustement...
« Reply #7 on: November 14, 2022, 11:09:54 pm »
Calculation of extremas was your loving task in math, or ?  ;D

Knowing the appx amplitude and the time is enough for me, because we´re not expecting surprising signals of the DUT in the testfield.. 8)

Online 2N3055

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Re: Most (Digital-)Scope are freezing while vertical adjustement...
« Reply #8 on: November 14, 2022, 11:16:56 pm »
Calculation of extremas was your loving task in math, or ?  ;D


 :-DD :-DD :-DD
"Just hard work is not enough - it must be applied sensibly."
Dr. Richard W. Hamming
 

Offline thm_w

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Re: Most (Digital-)Scopes are freezing while vertical adjustement...
« Reply #9 on: November 15, 2022, 12:31:15 am »
Can you edit it to a poll?
Profile -> Modify profile -> Look and Layout ->  Don't show users' signatures
 

Online nctnico

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Re: Most (Digital-)Scope are freezing while vertical adjustement...
« Reply #10 on: November 15, 2022, 12:41:48 am »
Calculation of extremas was your loving task in math, or ?  ;D

Knowing the appx amplitude and the time is enough for me, because we´re not expecting surprising signals of the DUT in the testfield.. 8)
Appearantly you are never involved in electronics development work. That is a world that can be full of surprises. Think of a circuit oscillating unexpectedly.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Online bdunham7

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Re: Most (Digital-)Scopes are freezing while vertical adjustement...
« Reply #11 on: November 15, 2022, 01:19:58 am »
So what do you think, when scope´s freezes while adjusting vertical line, is it a bug most scopes then got ?

No, IMO this is called 'not understanding what you are seeing'.  I'm not going to drag every scope I have onto the bench, so I'll just look at my SDS2354X+.

If you have a low amplitude signal and you stop the scope and then increase the sensitivity a few clicks, you'll see an expanded trace with lines in it due to the digital expansion.  Now if you set up the scope so that you have a fairly low refresh rate--whether due to low sweep rate, low pulse repetition rate or long holdoff time--you may briefly see the same thing as you expand the currently visible trace.  Furthermore, if you have persistence enabled, the scope (properly IMO) clears most of the persistence display and just shows you the most recent trace, expanded as appropriate, until it retriggers again.  If you do this with a varying signal--say AM modulated--then it may take some time to rebuild the persistence display.  These things might be misconstrued as the scope 'stopping' while the vertical knob is being moved.  I don't see any significant interruption of retriggering when adjusting the vertical and if it is there, it is a fraction of the normal retrigger time.
A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit 7.5 digit DMM is good enough for most people.
 
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Offline noisyee

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Re: Most (Digital-)Scopes are freezing while vertical adjustement...
« Reply #12 on: November 15, 2022, 01:39:38 am »

So what do you think, when scope´s freezes while adjusting vertical line, is it a bug most scopes then got ?
Keysight are mentioned not to do this, also GWInstek - Not all models.


Keysight does, even their new MXR. But much more responsive than its competitors - Keysight is always superb at.
I think all digital scopes will display history waveform rather than acquire in real time when adjusting. It's a matter of current time base setting, memory depth and the instruments' processing power. Almost all scopes will freeze at large time base or large memory depth, in which situation it's too hard to process in real time.
Some scopes choose to reacquire until adjusting is done, no matter what current settings are, so they "freeze". Maybe it's a limitation of the hardware, they can't refresh in time so it will make the scope slack if reacquiring-while-adjusting, or it's just a software issue to be optimize, who knows.
Some scopes, like Keysight, choose to periodic reacquire while adjusting at smaller time base or memory depth, so the displayed waveform flickers rather than freezes. Keysight scopes behave more like a analog one which is always welcomed.
 

Online Martin72Topic starter

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Re: Most (Digital-)Scopes are freezing while vertical adjustement...
« Reply #13 on: November 15, 2022, 06:53:34 am »
Hi,

Thankyou, I already knew this more or less.
"Goal" of the Thread is to explain that this behaviour isn't a bug in the scope's software, like someone might think.

Offline JPortici

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Re: Most (Digital-)Scopes are freezing while vertical adjustement...
« Reply #14 on: November 15, 2022, 07:03:08 am »
As i wrote in another thread
"like the "zoom out quirk"

it's really incredible what people fixate on. It's just another non issue.
"Doesn't work as i expect to (without ever reading the manual)" is different than "OMG ITS A BUG"

please dave don't do a video on this as well, the last few of this kind were very cringe
 
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Offline tautech

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Re: Most (Digital-)Scopes are freezing while vertical adjustement...
« Reply #15 on: November 15, 2022, 07:08:07 am »
Hi,

Thankyou, I already knew this more or less.
"Goal" of the Thread is to explain that this behaviour isn't a bug in the scope's software, like someone might think.
Think of it like this:
The modern DSO is a complex data acquisition system for which it makes no sense to maintain data while it is being adjusted.

To prove the point, engage Stats or a Histogram and see how user adjustments ruin the acquired results.  :horse:
Avid Rabid Hobbyist.
Some stuff seen @ Siglent HQ cannot be shared.
 

Online 2N3055

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Re: Most (Digital-)Scopes are freezing while vertical adjustement...
« Reply #16 on: November 15, 2022, 07:39:41 am »
.............................
Keysight scopes behave more like a analog one which is always welcomed.

Or not. I couldn't care less for fake analog like emulations.  It is aesthetical personal preference with no bearing to actual work in this case.

Like analog: do you think that trace should also have focus drift, and change intensity all the time while you change timebase..
"Just hard work is not enough - it must be applied sensibly."
Dr. Richard W. Hamming
 

Offline JPortici

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Re: Most (Digital-)Scopes are freezing while vertical adjustement...
« Reply #17 on: November 15, 2022, 07:51:12 am »
Hi,

Thankyou, I already knew this more or less.
"Goal" of the Thread is to explain that this behaviour isn't a bug in the scope's software, like someone might think.
Think of it like this:
The modern DSO is a complex data acquisition system for which it makes no sense to maintain data while it is being adjusted.

To prove the point, engage Stats or a Histogram and see how user adjustments ruin the acquired results.  :horse:

However one could argue that since the offset is applied in the analog domain the scope doesn't *need* to stop, you need to clear the measurements.
Anyway i believe the fuss is over the fact that until the recent past most people had seen TDS2000 and simillar scopes, with 2.5kS acquisitions. Indeed it looked istantaneous, because the scope was refreshing faster than their movement. With deep acquisitions, not so much.
 

Online 2N3055

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Re: Most (Digital-)Scopes are freezing while vertical adjustement...
« Reply #18 on: November 15, 2022, 08:41:13 am »
Hi,

Thankyou, I already knew this more or less.
"Goal" of the Thread is to explain that this behaviour isn't a bug in the scope's software, like someone might think.
Think of it like this:
The modern DSO is a complex data acquisition system for which it makes no sense to maintain data while it is being adjusted.

To prove the point, engage Stats or a Histogram and see how user adjustments ruin the acquired results.  :horse:

However one could argue that since the offset is applied in the analog domain the scope doesn't *need* to stop, you need to clear the measurements.
Anyway i believe the fuss is over the fact that until the recent past most people had seen TDS2000 and simillar scopes, with 2.5kS acquisitions. Indeed it looked istantaneous, because the scope was refreshing faster than their movement. With deep acquisitions, not so much.

Well that is the problem: offset is not really directly applied in analog domain...
That is not a potentiometer you're turning. It is an encoder. It will reconfigure analog path, but with software in the loop... Also there is a offset DAC and with certain screen display modes, you need to recalculate offset+signal to get propper absolute values and set screen scales.. And propagate that to math and measurements.
CRTs have absolute scales, DSO can have sliding scales (0 is the center or signal is the center modes)..
Scopes that work with decimated data will be faster doing that.... Less data buffers to reconfigure..

"Just hard work is not enough - it must be applied sensibly."
Dr. Richard W. Hamming
 
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Offline noisyee

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Re: Most (Digital-)Scopes are freezing while vertical adjustement...
« Reply #19 on: November 15, 2022, 10:11:31 am »
.............................
Keysight scopes behave more like a analog one which is always welcomed.

Or not. I couldn't care less for fake analog like emulations.  It is aesthetical personal preference with no bearing to actual work in this case.

Like analog: do you think that trace should also have focus drift, and change intensity all the time while you change timebase..

Yeah, I mean response faster like an analog one is welcomed. :)
I don't think refresh in real time when change setting is that important. But some scopes always show lagging display changing setting is really annoying.
 
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Online nctnico

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Re: Most (Digital-)Scopes are freezing while vertical adjustement...
« Reply #20 on: November 15, 2022, 11:50:30 am »
As i wrote in another thread
"like the "zoom out quirk"

it's really incredible what people fixate on. It's just another non issue.
I don't think you fully understand what is going on. What the Rigol seems to be doing is wait until the DSO thinks the user is done adjusting the vertical position for so long that it is perceived as lag. The magic number for humans to experience something without delay is somewhere between 100ms and 200ms. Wait longer, and it is perceived as laggy. So for a fluent user experience (which isn't a non issue!) it is better for a DSO to just try to put traces on the screen while the vertical position is adjusted. This helps both giving visual feedback to the user and prevent perceived lag.

Actually, this makes me wonder whether there is a similar lag / delay on the Rigol when you change the trigger level.
« Last Edit: November 15, 2022, 12:02:08 pm by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline alm

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Re: Most (Digital-)Scopes are freezing while vertical adjustement...
« Reply #21 on: November 15, 2022, 12:50:47 pm »
Anyway i believe the fuss is over the fact that until the recent past most people had seen TDS2000 and simillar scopes, with 2.5kS acquisitions. Indeed it looked istantaneous, because the scope was refreshing faster than their movement. With deep acquisitions, not so much.
Actually the old Tek digital scopes with CCDs had pretty low refresh rates compared to modern scopes. I see no reason why a scope sampling say 10 * 1 ms/div in 2.5 kS, which should take 10 ms to fill, would refresh any faster than a scope sampling 10 * 1 ms/div in 10 MS, which should also take 10 ms. It just has to sample faster and move more data, but any scope with such deep memory should be able to handle that, since that's the whole reason for buying a deeper memory scope.

Based on ntcnico's description it sounds more like a UI choice rather than anything dictated by the hardware.

Offline JPortici

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Re: Most (Digital-)Scopes are freezing while vertical adjustement...
« Reply #22 on: November 15, 2022, 12:58:30 pm »
I completely understand where the issue is. I used to have a rigol after all, or i wouldn't be so critical of the brand at all times.
Judging by the first impression video the vertical movement behaves exactly as it does with many other scopes I own, owned or used. Acquisition is stopped and current data is moved around so the user can see where it will be placed after the move.

Fine with me.
Maybe the lag after moving stuff around can be improved, maybe not.

What is not fine is what other OLDER rigol scopes used to so which was stop EVERYTHING and not even update the screen so you are guessing where it's going to be. That is not fine at all, that is a bug/poor design choice, and that is not what i saw in the first impression video.
 
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Offline joeqsmith

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Re: Most (Digital-)Scopes are freezing while vertical adjustement...
« Reply #23 on: November 15, 2022, 01:11:26 pm »
..
So what do you think, when scope´s freezes while adjusting vertical line, is it a bug most scopes then got ?
Keysight are mentioned not to do this, also GWInstek - Not all models.
..

I have no idea what you are saying.  I went back and looked at the thread and still wasn't sure.  Sounded like Dave had made some video but I skipped to the top post and nothing. 

So set any scope to say 1 second per division and then adjust the offset then change the gain.  Both adjustments will cause the scope to stop plotting.  So, assuming the scope isn't some Siglent POS with poor encoders,  if you continue to adjust say offset, the scope "freezes" the entire time.  Minutes, hours, days....    Once you stop making adjustments, the scope will start plotting where it left off or maybe it resets to T0 but in both cases it is not smooth.   

Online bdunham7

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Re: Most (Digital-)Scopes are freezing while vertical adjustement...
« Reply #24 on: November 15, 2022, 03:17:35 pm »
What the Rigol seems to be doing is wait until the DSO thinks the user is done adjusting the vertical position for so long that it is perceived as lag.

I don't know if this comes into play, but the fact that its acquisition is more than the one screenful (to support the zoom-out...) probably slows down its retrigger quite a bit.
A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit 7.5 digit DMM is good enough for most people.
 


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