Author Topic: True analog scopes  (Read 50449 times)

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Offline MrAl

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Re: True analog scopes
« Reply #325 on: December 26, 2022, 09:08:59 pm »
Something I don't miss at all with analogue scopes....all the mental arithmetic just to use the scope vs a DSO that when set correctly excludes all that BS and instead lets you focus on the DUT measurement instead.

Pinched from another thread as a fine example:

Apparently using a 100x probe.

 :horse:

Yes that's a good point the digital scopes can measure things right away.

I remember years ago trying to measure the rise, slope, and fall times of switching waveforms in high power converters so i could estimate the switching losses.  It took about 15 minutes to get right and the calculation had to be done on a calculator or computer.
If the scope could measure rise and fall times that would help.  Mine does not have that function though but i see some of the upper echelon scopes have that feature.

 

Offline baldurn

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Re: True analog scopes
« Reply #326 on: December 26, 2022, 09:22:45 pm »
I remember years ago trying to measure the rise, slope, and fall times of switching waveforms in high power converters so i could estimate the switching losses.  It took about 15 minutes to get right and the calculation had to be done on a calculator or computer.
If the scope could measure rise and fall times that would help.  Mine does not have that function though but i see some of the upper echelon scopes have that feature.

Does not require upper echelon scope. Just a newer scope. See attached screenshot of what my humble little entry level scope can do.
 

Online tggzzz

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Re: True analog scopes
« Reply #327 on: December 26, 2022, 09:24:33 pm »
I remember years ago trying to measure the rise, slope, and fall times of switching waveforms in high power converters so i could estimate the switching losses.  It took about 15 minutes to get right and the calculation had to be done on a calculator or computer.

Taking 15mins to work out a rise/slopes/fall times seems long. How long did you take to work out a peak-peak voltage?

OTOH, if it was such an awkward waveform or triggering, what leads you to believe a general purpose scope would have made the same choices?

I can understand that setting up the experiment and transcribing measurements into a very slow computer might have taken 15 mins.
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Online tggzzz

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Re: True analog scopes
« Reply #328 on: December 26, 2022, 09:28:51 pm »
I remember years ago trying to measure the rise, slope, and fall times of switching waveforms in high power converters so i could estimate the switching losses.  It took about 15 minutes to get right and the calculation had to be done on a calculator or computer.
If the scope could measure rise and fall times that would help.  Mine does not have that function though but i see some of the upper echelon scopes have that feature.

Does not require upper echelon scope. Just a newer scope. See attached screenshot of what my humble little entry level scope can do.

I would have thought that if traceability and reproducibility was required, then there would be reluctance to rely on a complex black box calculation.

Spreadsheets (and computer programs) often contain errors, but they can be challenged, examined and corrected in a way that firmware cannot.
There are lies, damned lies, statistics - and ADC/DAC specs.
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Offline baldurn

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Re: True analog scopes
« Reply #329 on: December 26, 2022, 09:35:17 pm »

I would have thought that if traceability and reproducibility was required, then there would be reluctance to rely on a complex black box calculation.

Spreadsheets (and computer programs) often contain errors, but they can be challenged, examined and corrected in a way that firmware cannot.

If you enable the statistics function to gather data for more than just one random screenshot, there simply is no alternative?

If it is just for one random screenshot, just include that screenshot. Anyone can reproduce the calculation, albeit probably not as precise.
 

Offline Fungus

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Re: True analog scopes
« Reply #330 on: December 26, 2022, 10:20:36 pm »
If the scope could measure rise and fall times that would help.  Mine does not have that function though but i see some of the upper echelon scopes have that feature.

It's an entry-level feature these days. Even the venerable Rigol DS1054Z does it.

 

Offline AVGresponding

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Re: True analog scopes
« Reply #331 on: December 26, 2022, 10:21:23 pm »
Something I don't miss at all with analogue scopes....all the mental arithmetic just to use the scope vs a DSO that when set correctly excludes all that BS and instead lets you focus on the DUT measurement instead.

Pinched from another thread as a fine example:

Apparently using a 100x probe.

 :horse:

Yes that's a good point the digital scopes can measure things right away.

I remember years ago trying to measure the rise, slope, and fall times of switching waveforms in high power converters so i could estimate the switching losses.  It took about 15 minutes to get right and the calculation had to be done on a calculator or computer.
If the scope could measure rise and fall times that would help.  Mine does not have that function though but i see some of the upper echelon scopes have that feature.

That's a Tek TDS display. My TDS420A can measure rise times, and fall times. In fact it has 7 pages of things it can measure (4 items to a page in fairness).

How much did I pay for this upper echelon 'scope? £100. Shipped.
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Online tggzzz

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Re: True analog scopes
« Reply #332 on: December 26, 2022, 10:38:35 pm »

I would have thought that if traceability and reproducibility was required, then there would be reluctance to rely on a complex black box calculation.

Spreadsheets (and computer programs) often contain errors, but they can be challenged, examined and corrected in a way that firmware cannot.

If you enable the statistics function to gather data for more than just one random screenshot, there simply is no alternative?

If it is just for one random screenshot, just include that screenshot. Anyone can reproduce the calculation, albeit probably not as precise.

MrAl was doing a complex test-specific calculation of switching losses, not a simple standard stats function.  If the measurement is important, it needs to be visible and reproduceable, which is questionable if done inside one specific instrument. (just like a spreadsheet calculation without the formulae being visible)

Here's the relevant context you snipped...
I remember years ago trying to measure the rise, slope, and fall times of switching waveforms in high power converters so i could estimate the switching losses.  It took about 15 minutes to get right and the calculation had to be done on a calculator or computer.
If the scope could measure rise and fall times that would help.  Mine does not have that function though but i see some of the upper echelon scopes have that feature.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Online tggzzz

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Re: True analog scopes
« Reply #333 on: December 26, 2022, 10:40:51 pm »
If the scope could measure rise and fall times that would help.  Mine does not have that function though but i see some of the upper echelon scopes have that feature.

It's an entry-level feature these days. Even the venerable Rigol DS1054Z does it.

If his.calculation was that simple, why did it take 15 mins? If it took 15mins, it would have been so specific and complex that it wouldn't have been a standard scope feature.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline baldurn

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Re: True analog scopes
« Reply #334 on: December 26, 2022, 11:18:39 pm »

MrAl was doing a complex test-specific calculation of switching losses, not a simple standard stats function.  If the measurement is important, it needs to be visible and reproduceable, which is questionable if done inside one specific instrument. (just like a spreadsheet calculation without the formulae being visible)


Yes and how do you know how precise that measurement is if you do not do statistics on it? Just to be sure, since this thread IS about analog vs DSO, how would you do it with an analog scope (a true analog scope, not those half digital things that can do digital measurements)? I am actually curious and does not know the answer. Would it not be in fact be hard and time consuming to get the same level of precision, that we get by default just by pressing the stat button?
 

Online tautech

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Re: True analog scopes
« Reply #335 on: December 26, 2022, 11:55:54 pm »
I remember years ago trying to measure the rise, slope, and fall times of switching waveforms in high power converters so i could estimate the switching losses.  It took about 15 minutes to get right and the calculation had to be done on a calculator or computer.
If the scope could measure rise and fall times that would help.  Mine does not have that function though but i see some of the upper echelon scopes have that feature.

Does not require upper echelon scope. Just a newer scope. See attached screenshot of what my humble little entry level scope can do.
Yeah but they are just measurements and sure you can use/apply them for the measurement MrAl was trying to do but in you 2kX+ the PA feature is a far better solution however for best accuracy all/any probes need be de-skew'ed.
Trouble is to complete the full range of PA measurements differential and current probes are required but at least with your 'newer scope' within PA you have connection guides for each type of PA measurement.
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Offline mag_therm

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Re: True analog scopes
« Reply #336 on: December 27, 2022, 12:22:04 am »
My reply #39 was perhaps a little sarcastic, but that was why I think DSO are not well enough developed yet, still not easy to set up and use, and settings are not persistent and further, not easily accessible or readable.
Also users who rely on capturing a file from equipment to take  back to office, have lost the ability to quickly visualize a problem.

Imagine a 5000 kW inverter that is intermittently tripping at full power.
So we need to run  it at full power with scope probes on it. Shut down, safety rules, blah-blah, change probe position, reset scope, restart
... over and over to find where the problem might be.
It might take 4 to 8 persons, engineers, electricians  mill operators, safety man  etc 4 to 24 hours or 40 hours to do all this.
Then consider what to do with, and the cost of, wasted product. Then consider the down time, loss of production per hour if this unit is mission critical.

When DSO came into use, I saw a step: that it can take the electrician or electronics technician half an hour or more to get usable traces from a basic DSO. Do a setting change to home in on a problem... more delays.  Everybody else standing around and waiting, line shut down.
That was not only anecdote, I saw it as trend in many countries.
And I could compare that to times when we had the old type scopes and recorders which were faster and easier to use.
 

Offline mwb1100

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Re: True analog scopes
« Reply #337 on: December 27, 2022, 01:05:24 am »
When DSO came into use, I saw a step: that it can take the electrician or electronics technician half an hour or more to get usable traces from a basic DSO. Do a setting change to home in on a problem... more delays.  Everybody else standing around and waiting, line shut down.
That was not only anecdote, I saw it as trend in many countries.
And I could compare that to times when we had the old type scopes and recorders which were faster and easier to use.

This sounds like a technician who is not very well trained or experienced with the test equipment.  Would a similarly untrained technician be able to get results quicker with an analog scope?
 

Offline mag_therm

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Re: True analog scopes
« Reply #338 on: December 27, 2022, 01:38:03 am »


This sounds like a technician who is not very well trained or experienced with the test equipment.  Would a similarly untrained technician be able to get results quicker with an analog scope?
That is an interesting question, and I don't think easy to find out the answer.
That is because new starters in electronics will usually not be exposed to old tech.

I read the aircraft pilots forums where all the present incidents/accidents are discussed.

One of the near disasters was the Qantas flight out of Singapore where an oil pipe in engine broke,
in an early model A380. nearly leading to disaster.
On the flight deck were extra pilots, trained in the management systems.
However they, even collectively,  could not identify key issues, and were searching ( I call "pecking" ) through menus and following procedures,
until fortunately, the aircraft landed safely under manual control.
I may have it a bit wrong, but the official findings are interesting.

We also have stay focussed on the fact that high value engineered stuff stays current for 25 years or more.
That is aircraft, military, space, large industrial , electric power etc.

My opinion is that the underlying tech on the present range of ordinary DSO is following best practice, but the HMI, ergonomics, "intuitiveness" is poor.
 

Online tautech

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Re: True analog scopes
« Reply #339 on: December 27, 2022, 01:49:03 am »
My reply #39 was perhaps a little sarcastic, but that was why I think DSO are not well enough developed yet, still not easy to set up and use, and settings are not persistent and further, not easily accessible or readable.
Also users who rely on capturing a file from equipment to take  back to office, have lost the ability to quickly visualize a problem.
Consider also the scope novice encountering a waveform they need consult a mentor to understand what they see/have captured.....this is the real power of a DSO that experienced engineers seem to always fail to see.  :-//

This sounds like a technician who is not very well trained or experienced with the test equipment.  Would a similarly untrained technician be able to get results quicker with an analog scope?
My opinion is that the underlying tech on the present range of ordinary DSO is following best practice, but the HMI, ergonomics, "intuitiveness" is poor.
Nothing new, all models of scopes have always offered a different UI presenting just another challenge for the user to learn.
Really the modern DSO is set out on a logical manner with most commonly used features in the top level of menus.
The only difference is one must train oneself to understand the simple logic of where everything is.....press a channel button and everything relating to the channel input is there, coupling, 0V pos, invert, input attenuation and so on.
Greybeards go on as if this basic stuff is from some other planet.  :-//
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Offline asis

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Re: True analog scopes
« Reply #340 on: December 27, 2022, 01:52:32 am »
Interesting discussion here.

The fact is that no matter how prepared an electronics engineer is, he is not able to quickly make a decision and choose a means of measurement (any) because he needs to quickly restore all previously acquired skills in order to apply them to analyze events.


Well, let's imagine the situation using the example of Neuralink developers with a multi-channel, essentially analog oscilloscope which does not even have any intelligible synchronization.
How should he interpret what he sees in this stream?
 

Offline mag_therm

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Re: True analog scopes
« Reply #341 on: December 27, 2022, 02:05:35 am »

Greybeards go on as if this basic stuff is from some other planet.  :-//
[/quote]

I as graybeered give example of "poor" HMI based on the GWI1202B here

A most basic selection is trigger source.
It requires  3 "pecks" to get the menu followed by a "screwing around" the Variable knob which has no detents.
Try to align it with the selection.
That really puts me off using it.
 I will let the 17 year old here try it and ask him.
 

Offline aeg

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Re: True analog scopes
« Reply #342 on: December 27, 2022, 02:08:34 am »
Something I don't miss at all with analogue scopes....all the mental arithmetic just to use the scope vs a DSO that when set correctly excludes all that BS and instead lets you focus on the DUT measurement instead.

Pinched from another thread as a fine example:


OK, I'll bite... If the DSO excludes all the BS, what's that to the left of the rising edge?

Hint: transcendental functions
 

Online tautech

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Re: True analog scopes
« Reply #343 on: December 27, 2022, 02:11:45 am »
tautech said:
Quote
Greybeards go on as if this basic stuff is from some other planet.  :-//


I as graybeered give example of "poor" HMI based on the GWI1202B here

A most basic selection is trigger source.
It requires  3 "pecks" to get the menu followed by a "screwing around" the Variable knob which has no detents.
Try to align it with the selection.
That really puts me off using it.
 I will let the 17 year old here try it and ask him.
So you have a bad experience with a single brand and you throw all DSO's by implication into the same group ?

That's like saying all opamps are crap just because you can't get one to work like you want to.
« Last Edit: December 27, 2022, 02:26:26 am by tautech »
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Online tautech

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Re: True analog scopes
« Reply #344 on: December 27, 2022, 02:29:25 am »
Something I don't miss at all with analogue scopes....all the mental arithmetic just to use the scope vs a DSO that when set correctly excludes all that BS and instead lets you focus on the DUT measurement instead.

Pinched from another thread as a fine example:


OK, I'll bite... If the DSO excludes all the BS, what's that to the left of the rising edge?

Hint: transcendental functions
Gibbs ears, if that's what you mean, DSO's do that too.
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Offline mag_therm

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Re: True analog scopes
« Reply #345 on: December 27, 2022, 02:41:56 am »

So you have a bad experience with a single brand and you throw all DSO's by implication into the same group ?

That's like saying all opamps are crap just because you can't get one to work like you want to.
Is SDS1000CML current or obsolete? Looks like I can still buy one.
 

Online tautech

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Re: True analog scopes
« Reply #346 on: December 27, 2022, 02:49:04 am »

So you have a bad experience with a single brand and you throw all DSO's by implication into the same group ?

That's like saying all opamps are crap just because you can't get one to work like you want to.
Is SDS1000CML current or obsolete? Looks like I can still buy one.
Current and now a + version with LAN and other stuff I don't remember....maybe a higher res display than earlier models.
We don't bother with them as the SDS1202X-E is too much next level compared to the older CML design.
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Offline mag_therm

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Re: True analog scopes
« Reply #347 on: December 27, 2022, 02:59:50 am »
Here, SDS1202X-E  is discontinued and replaced  " SDS1202X+ (DISCONTINUED > SEE SDS1000X-E SERIES)"

Any way these things seem all about same price and tarred by the same brush, see page 33 of SDS1000CML manual.
That is same problem I have with excessive menu depth on the GWInstek.
What is your comment on that?
 

Offline BillyO

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Re: True analog scopes
« Reply #348 on: December 27, 2022, 04:09:03 am »
Greybeards go on as if this basic stuff is from some other planet.  :-//
Hey, don't paint us all with the same brush.  @65yo I'm a greybeard, but I still like, understand and use DSOs.  I still love my old CRO too, though.
Bill  (Currently a Siglent fanboy)
--------------------------------------------------
 

Offline mag_therm

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Re: True analog scopes
« Reply #349 on: December 27, 2022, 04:33:09 am »
To further my argument that these el cheapo basic  DSO have "poor" HMI:
Both of the following oscilloscopes are on the bench here, (along with a Tek 466, not mentioned here).

Audio work, for example,

Eico TR410 1 CH (year about 1963):
Display area ~ 120 by 120 mm circle
Front panel 200 W by 270 H
Approx 23 control positions status all visible

GWI 1202B 2CH (year about 2017):
Display area ~ 120 by 80 mm rectangle
Front panel 380 W by 200 H
Approx 49 control positions status press/not visible plus menus up to 3 deep, too numerous to count, most status not visible.
(There are 6 controls and underlying menus  dedicated for CH2 and Math)
 


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