Author Topic: Do You still use analog oscilloscopes in 2019?  (Read 13449 times)

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Online Mr. Scram

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #150 on: August 07, 2019, 04:56:01 pm »
Using my finger, I have done exactly that on a non-storage scope, many times.

Sure a digital scope would have made it easier, but it didn't give me any more useful information.
How does that work? You just go crazy on the button and hope the oscilloscope shows anything useful?
 

Offline GregDunn

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #151 on: August 07, 2019, 05:19:44 pm »
Reading this topic reminded me of a quote that I recall but can't find it again, I recall it was Chuck Yeager at an airshow - a P51 was being compared to a modern jet and someone was extolling the virtues of the P51 - his reply was to the effect of - don't get sentimental - old gear is fine for restoration - but almost always the most modern is the best - something like don't bring a knife to a gun fight.

This is also from a guy (Yeager) so full of himself that he could not be bothered to check his fuel state resulting in a research F-105 crashed into the desert while joy riding.

And who destroyed an NF-104 (as poorly dramatized in The Right Stuff) because he was unwilling/unable to follow the designed flight profile.  He only escaped from that debacle because the court martial board was unwilling to censure him.  A talented pilot, but a little too quick to criticize the educated people.
 

Offline tggzzz

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #152 on: August 07, 2019, 06:44:50 pm »
Using my finger, I have done exactly that on a non-storage scope, many times.

Sure a digital scope would have made it easier, but it didn't give me any more useful information.
How does that work? You just go crazy on the button and hope the oscilloscope shows anything useful?

The technique was described earlier in this thread
https://www.eevblog.com/forum/testgear/do-you-still-use-analog-oscilloscopes-in-2019/msg2599065/#msg2599065

It works; try it and see
There are lies, damned lies, statistics - and ADC/DAC specs.
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Offline David Hess

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #153 on: August 07, 2019, 07:25:19 pm »
How would you make something like button bounce reliably repetitive?

Using my finger, I have done exactly that on a non-storage scope, many times.

Sure a digital scope would have made it easier, but it didn't give me any more useful information.

I have done in that way also when I lacked a storage oscilloscope.  It works but using a storage oscilloscopes makes it much easier.
 

Offline bd139

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #154 on: August 07, 2019, 07:42:57 pm »
Right tools for the job. Use a universal counter for debouncing stuff  :-//
Putting a universal counter on every button of my products made for steep prices. ;D It's not about debouncing, it's about knowing how big your bounce is so you can build a debounce mechanism with purpose whether it's hard- or software.

Pin change interrupt / scan. Disable interrupt/scan. Set timer for 50ms. Handle whatever button was supposed to do. Timer fires, turn on interrupt/scan again, disable timer.

Hardware? Fuck it. It’s 2019. Cheaper to do it in software. I actually used a PIC10F320 to do this recently and replace two logic ICs. 

How would you make something like button bounce reliably repetitive?

Using my finger, I have done exactly that on a non-storage scope, many times.

Sure a digital scope would have made it easier, but it didn't give me any more useful information.

I have done in that way also when I lacked a storage oscilloscope.  It works but using a storage oscilloscopes makes it much easier.

That’s quite funny. Back in the distant past we turned the lab lights out and pulled down the blinds and shut our eyes for 30 seconds to increase trace persistence.
 

Offline David Hess

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #155 on: August 07, 2019, 07:49:41 pm »
That’s quite funny. Back in the distant past we turned the lab lights out and pulled down the blinds and shut our eyes for 30 seconds to increase trace persistence.

I did that but also made a shade out of paper and taped it to the oscilloscope.
 

Online tautech

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #156 on: August 07, 2019, 08:07:36 pm »
A Persistence button is easier to use that a viewing hood !  :P
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Online Mr. Scram

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #157 on: August 07, 2019, 08:09:25 pm »
Pin change interrupt / scan. Disable interrupt/scan. Set timer for 50ms. Handle whatever button was supposed to do. Timer fires, turn on interrupt/scan again, disable timer.

Hardware? Fuck it. It’s 2019. Cheaper to do it in software. I actually used a PIC10F320 to do this recently and replace two logic ICs. 


That’s quite funny. Back in the distant past we turned the lab lights out and pulled down the blinds and shut our eyes for 30 seconds to increase trace persistence.
If software was free a lot of people would be out of a job. Regardless, offloading to hardware has its pros and cons.
 

Offline David Hess

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #158 on: August 08, 2019, 01:39:10 am »
A Persistence button is easier to use that a viewing hood !  :P

Well, I did eventually buy a Tektronix 7834 analog storage oscilloscope and my go to instrument is a 2232 combination analog and DSO; both are one button push away from persistence or digital storage.  I would use a modern dedicated DSO if I found an affordable and acceptable one but that ended up being the 2232.
 

Offline scatterandfocus

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #159 on: August 11, 2019, 06:17:36 pm »
I thought my first scope would be a low cost used analog one.  It turned out to be a dud.  So that got me looking at dso's.  Navigating that world of interdependent specifications, models which has this feature or that feature (and actually works as expected), firmware bugs, hardware bugs, which companies actually reasonably support their products, has turned out to be a confusing mess eating up weeks of free time.  So now I guess I'm back to looking at old analog scopes where everything seems much more straightforward.  It's just a matter of finding a seller who isn't trying to pass off junk at a high price.
« Last Edit: August 11, 2019, 06:22:33 pm by scatterandfocus »
 

Offline 0culus

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #160 on: August 11, 2019, 06:43:41 pm »
I mean, my work area now has both a Tek 7904A and a 7104 sitting beside it, so my persuasion is clear. However, I'm thinking I'll look into an older Tek DPO eventually. I have one at work, and once it gets booted the scope itself works pretty damn well. The DPO FastAcq features are useful for hunting rare glitches, and I can get into one for a price that I can afford for personal use. Plus if I find the right connector cable, I can connect it to my TLA715 logic analyzer system.
« Last Edit: August 11, 2019, 06:46:04 pm by 0culus »
 

Offline bob91343

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #161 on: August 12, 2019, 07:44:06 pm »
Scatrter, what are you looking for in a used analog 'scope?  I now have four of them plus one digital.  They are all Tektronix of varying age and specification.  One in the ham shack, one at the work bench, two in the closet, plus the digital on the bench.  The ones in the closet are backup; I have this dread of not having a decent working unit.
 

Offline scatterandfocus

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #162 on: August 13, 2019, 01:36:25 am »
Bob, probably nothing much in terms of what many people seem to be using scopes for.  I'm mostly interested in analog audio with some automotive uses on the side.

The seller of the dud scope that I received has offered to replace it with another unit.  So I'll see how that goes.

On dso's, I guess I don't get much of what they are about.  Oscilloscopes are for looking at  waveforms, right?  Meters are for accurately checking voltage and current.  Spectrum analyzers are  for looking at the frequency domain.   Logic analyzers are for looking at digital signals.  So then, why is so much piled into these low cost dso's?  Who is it all for?  Does a dso give better voltage and current measurements than a meter?  Does it provide better FFT than an analyzer?  Better decoding than a logic analyzer? Better waveform display than an analog oscilloscope?  A better interface than dedicated instruments?  I guess the only real strength that I see of dso's is the storage aspect.  But in what cases is it needed to store waveforms rather than just looking at them in realtime?  Is storage a necessity or just a nicety?  And when looking at dso's, I'm asking myself if I really need what they provide, the same as asking myself if I need an arbitrary waveform generator over a simpler audio generator.  And if I get a dso, will I still be using it in 10-20 years, or will it be technically obsolete in 5 years and not repairable when it breaks?
« Last Edit: August 13, 2019, 01:49:34 am by scatterandfocus »
 

Offline 0culus

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #163 on: August 13, 2019, 01:44:23 am »
Storage becomes real handy when you're looking for a rare event (as do complex triggers). 
 

Offline scatterandfocus

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #164 on: August 13, 2019, 01:50:18 am »
Oculus, in what practical use cases? 
 

Offline CatalinaWOW

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #165 on: August 13, 2019, 02:02:34 am »
I'll reply for Oculus since I have found storage useful since I was using it in analog storage scopes.  You have a noise problem.  It only causes a problem when the noise spike lines up with an edge of a signal in your device.  When that occurs something happens that shouldn't.  Now how do you identify where that spike is coming from?  You look at possible offending lines, signals that have energy in them so they might be the source of the crosstalk.  But which one is it?  You trigger on the offending event.  It happens only every so often so it is a blip on the screen, but when you can store, digital or analog you can see what is happening at your gate and on the candidate offender.  When you find one that lines up you have your culprit. 

Both digital and analog storage work for this, but digital made it cheaper and more versatile.
 

Offline scatterandfocus

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #166 on: August 13, 2019, 02:17:00 am »
CatalinaWOW, I assume that you are looking for glitches in digital signals.  I don't know if that will ever be a practical use case for myself.  And if I do have a need for that in the future, I think I would have a better idea of what I need at that point (rather than now).  And as tech marches on, there will likely be better tools for that task in the future.
« Last Edit: August 13, 2019, 02:25:06 am by scatterandfocus »
 

Offline 001

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #167 on: August 13, 2019, 07:00:21 am »
Thanck You! This tread is awesome  :-+
 

Offline tggzzz

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #168 on: August 13, 2019, 07:03:39 am »
Bob, probably nothing much in terms of what many people seem to be using scopes for.  I'm mostly interested in analog audio with some automotive uses on the side.

The seller of the dud scope that I received has offered to replace it with another unit.  So I'll see how that goes.

On dso's, I guess I don't get much of what they are about.  Oscilloscopes are for looking at  waveforms, right?  Meters are for accurately checking voltage and current.  Spectrum analyzers are  for looking at the frequency domain.   Logic analyzers are for looking at digital signals.  So then, why is so much piled into these low cost dso's?  Who is it all for?  Does a dso give better voltage and current measurements than a meter?  Does it provide better FFT than an analyzer?  Better decoding than a logic analyzer? Better waveform display than an analog oscilloscope?  A better interface than dedicated instruments?

In general, no it is not better, but it is often good enough. But that requires defining "better" and "good enough".

Fundamentally you should use the tools available, understanding their limitations and using imagination to work around the limitations.

Quote
I guess the only real strength that I see of dso's is the storage aspect.  But in what cases is it needed to store waveforms rather than just looking at them in realtime?  Is storage a necessity or just a nicety? 

That is indeed the killer use case. It is needed for single-shot events, e.g. PSU switch on/off behaviour. For events that can be made repetitive, it is not an advantage. "Repetitive" is within the limitations of the CRT's phosphor's time constant.

Quote
And when looking at dso's, I'm asking myself if I really need what they provide, the same as asking myself if I need an arbitrary waveform generator over a simpler audio generator.  And if I get a dso, will I still be using it in 10-20 years, or will it be technically obsolete in 5 years and not repairable when it breaks?

That is indeed a question with modern equipment, not just scopes. The low-cost of some scopes makes them disposable items. When bought new, a Tek 465 cost about a year's salary :)

If you are interested in audio, then you are probably interested in low-level signals. A lower bandwidth scope can have more sensitive vertical settings. With digital scopes you have to be very careful to understand the consequences of the ADC, particularly the effective number of bits and linearity.
There are lies, damned lies, statistics - and ADC/DAC specs.
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Offline 2N3055

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #169 on: August 13, 2019, 08:32:15 am »
Oculus, in what practical use cases?

If I may add few thoughts.. You can have glitches on analog signals, injected from some sort of interference (mobile tower, some sort of machinery, garage opener etc etc..) or from a separate faulty circuit in same device. As already mentioned, you need to verify startup sequence of PSU, sometimes several voltages at he same time to see if sequence of events is right. There are all sorts of circuits that are automating some sequence of events (open this valve, 100 msec later enable 12V, sometime later  do this and that.) You can have a problem with a walkie talkie that flashes the display when you press TX, and it overheats quickly when you do that so you really want to do this as little as possible.

And on and on.

Many many years ago, we used to have ampermeters, and voltmeters, and ohmmeters. As separate instruments. Even had them separate for different ranges: 10V voltmeter and 100V voltmeter and a separate 500V AC voltmeter. And at one point, people realized they could put one one moving coil instrument in a box with switches and different shunts and resistors and a battery and a multi-meter was born. After many years they became digital, they started measuring temperature, capacitance, frequency etc etc...
Today nobody wants to use anything else. There are no people saying "we should be using old analog ampermeters, those are better" That would be just silly.

Modern digital scope is really a "signal multi-meter". In addition to showing repetitive waveforms it can measure hundreds of other parameters. Better ones have whole analysis packages built in. That saves time and enables you to use different, faster and better workflows..

Regards
 

Offline tggzzz

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #170 on: August 13, 2019, 08:42:25 am »
There are no people saying "we should be using old analog ampermeters, those are better" That would be just silly.

Ooh, a challenge.

Try measuring charge with a modern meter.

At school we measured charge using a ballistic galvanometer. Principle: dissipate the charge through the meter in a time that is much shorter than the meter's response time. The needle is kicked and the maximum deflection is proportional to the current*time, i.e. charge.
There are lies, damned lies, statistics - and ADC/DAC specs.
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Offline bd139

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #171 on: August 13, 2019, 08:50:24 am »
I prefer analogue ammeters for watching change. They are also much faster responding when you consider the brain has to interpret the value and the value trend. Flitting digits is hopeless. The analogue bargraph on most DMMs is totally hopeless as well. I include the 87V there.

Thus I use these rather nice analogue ammeters on a regular basis...



I probably nearly never use the DMM current ranges. I usually use it in volts and measure across a resistor if I need current. Mainly because I don't have to futz with changing the leads then.

Incidentally they also seem to promote intense concentrate on accuracy which isn't actually that important in perhaps 80% of cases. Hmm it's 1.063 amps vs it's 1 amp.
« Last Edit: August 13, 2019, 08:53:28 am by bd139 »
 
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Online Mr. Scram

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #172 on: August 13, 2019, 09:06:10 am »
I prefer analogue ammeters for watching change. They are also much faster responding when you consider the brain has to interpret the value and the value trend. Flitting digits is hopeless. The analogue bargraph on most DMMs is totally hopeless as well. I include the 87V there.

Thus I use these rather nice analogue ammeters on a regular basis...



I probably nearly never use the DMM current ranges. I usually use it in volts and measure across a resistor if I need current. Mainly because I don't have to futz with changing the leads then.

Incidentally they also seem to promote intense concentrate on accuracy which isn't actually that important in perhaps 80% of cases. Hmm it's 1.063 amps vs it's 1 amp.
 

Offline edigi

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #173 on: August 13, 2019, 09:22:24 am »
So then, why is so much piled into these low cost dso's?  Who is it all for?

In the last couple of decades so much has changed in the electronics that that the role of oscilloscopes has changed also significantly. Naturally one thing has not changed: An expensive dedicated test equipment is typically better in what it's dedicated for (cheap ones not necessarily).
Nevertheless a decent DSO can be a substitute for some of those dedicated equipment (especially for hobbyist if they don't have very demanding requirements from them in certain areas, or big $ pocket which is actually kind of the same thing).

Thus these low cost DSOs are mostly for hobbyist (in my country I know that some repair shops are using them). There are couple of equipment that one cannot avoid even as hobbyist and DSO is one of them. For DSO vendors those extra features costs from little to nothing. Just SW on existing HW.

Although the main role of looking at  waveforms like you wrote, but not only that.
This has to do a lot with how electronics has changes in the last couple of decades. Back the majority of the stuff was analogue (well with some exceptions like 74 series of ICs and 8051 micro that arrived gradually).
Deep down naturally still everything is analogue, however from practical purposes real analogue stuff (where core functionality is still analogue) has remained only a few places.

Today most of the signal generation and processing has transferred to digital domain. (This does not necessarily mean DSPs as MCUs have become quite powerful, many times MCUs are used instead). For fast logic CPLDs and FPGAs are used even by hobbyist.
Thus we have purpose made chips that communicate via some interface (like SPI and SPI can use fast bitrates...) and generic chips where logic is defined via some HDL language (and where really fast communication is needed  e.g. LVDS is used).

Naturally if you work with analogue audio and periodic signals (and couple of more areas) none of these change impacts you.
However most of us that has something to do with modern electronics are very much impacted.

Naturally even in these realms some signals can be made periodic. However sometimes it becomes increasingly hard, sometimes downright impossible. E.g. although I've occasionally did, I'm generally unwilling to change HDL code to make something periodic as the synthesized HW will be different and glitches invisible because of the difference made.

Spectrum analyzers are  for looking at the frequency domain.

Sure. However DSO has the high impedance input and can provide better resolution for lower frequency ranges. Potentially you may have probes for the DSO that even if you could have for SA, you'd rather not duplicate them for pure economical reasons.
I can't emphasize enough the probing part of this story.

]
Logic analyzers are for looking at digital signals.

Sure again. Logic analyzers have the same probing issue again if you work with fast signals (and even couple of $ MCUs can produce such fast signals nowadays that without proper probing your analyzer fails to see or even worse potentially corrupts it). This has been recently discussed in the forum and it worth checking these 2 videos (sorry for reiterating again):

[001] Sigrok and Logic Analyzers


[009] DSLogic Logic Analyzer Review and Teardown


So while some vendors tried to address the problem, and certainly there is generic solution in the nxk$ domain, if the number of signals that you need to check does not exceed what your DSO is capable of DSO is actually comes very handy in case of fast signals.

Better waveform display than an analog oscilloscope?

I guess it heavily depends on how you define the term better.
I'd rather look for better triggers as there is no replacement for that.

So as short version: killer use cases for DSO, single-shot events (including protocol decoding), probes that you have available for fast signals, FFT and so on.
I guess everyone who has switched to DSO (almost everybody based on the offerings of the oscilloscope vendors) has at least one good enough reason, since DSOs tend to be significantly more expensive than the analogue oscilloscopes that you find.
 
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Offline bd139

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Re: Do You still use analog oscilloscopes in 2019?
« Reply #174 on: August 13, 2019, 09:24:34 am »
Re: the Keithley....

I'm honestly not sure why that exists. Say I'm looking at PA transistor current. As the transistor gets hotter, current goes up. Difficult to read trends over a 5 second period with any kind of digital metering. The real time trend graph is good for sure but you can see the same thing watching a needle creep up and it doesn't cost $1750 which is a bad ROI unless you spend all day looking at it. If I want to log something over time then use a generic bench meter with a PC interface and do it there. Very limited in what you can do with the data on a device when there's Excel and Mathematica available on something larger and more powerful.

Some analogue action from me to demonstrate the current metering response...



 


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