Analog versus digital oscilloscopes 2 - Page 1
Forum section: electronics / beginners

author: Trader
author_rank: Frequent Contributor
timestamp: July 29, 2021, 04:09:45 pm
content: I don't know why the post (https://www.eevblog.com/forum/beginners/analog-versus-digital-oscilloscopes/) was closed, but I think this is an interesting topic and there is no need for censorship in a technical forum. A lot of people can learn about the technical differences, advantages, and disadvantages over the years.Talking about PRICE, a good Analog scope is MUCH better than a good Digital Scope.Most of the time you just need to see Signals, you don't need fancy options as serial communication or FFT, etc; it is better to use a dedicated logic or spectrum analyzers.I'm not sure what is the analog scope with the highest bandwidth, but up to 500MHz, a good analog scope will cost between 1/3 or 1/10 of a Rigol MSO5074 or Siglent SDS2104X Plus (hobbyist or officially upgraded) and 1/10 or 1/30 of a Tektronix, Keysight, Rohde & Schwarz, LeCroy, etc.And, as I said, 99% of the time you just want to see the waves. (good analog scopes also created several excellent features to compensate for the lack of storage.)PS: Or an "intermediary" Digital Phosphor Oscilloscope (DPO); there are +-1GHz models costing similar to a 100MHz DSO.

author: TimFox
author_rank: Super Contributor
timestamp: July 29, 2021, 04:16:44 pm
content: Just as with "real cameras", i.e. film-based, it is hard to find good analog oscilloscopes anymore. Similarly, I won't give up mine (or my large-format film cameras) in this life.My basic reply to this question, based on many years with both, is that if you don't know what the problem is, it is better to start with an analog oscilloscope (with sufficient bandwidth).If you know what's going on, but need to make a measurement, the digital oscilloscope is better. Similarly, if you need to freeze a waveform, especially a non-periodic waveform, the digital oscilloscope is better.One technology for which I have no nostalgia is the analog storage oscilloscope.

author: Siwastaja
author_rank: Super Contributor
timestamp: July 29, 2021, 04:47:09 pm
content: All details about some quantization effects are totally unimportant.The large difference is that basically what is called a "digital oscilloscope" today is astorage oscilloscope, and very good at said storage features.While analog storage oscilloscopes exist, they are way more limited in this "storage", and most analog scopes beginners buy are not storage oscilloscopes at all.The big difference here is, a storage oscilloscope cancaptureandstorea waveform, for example, to record one incident, be it a digital communication packet, or a non-repetitive analog phenomenon like someone shouting an obscenity at a microphone, or recording an earthquake. You can record quite long observations, then zoom in and out, scroll it...Analog oscilloscopes are pretty good to observerepetitivesignals, for example to look at how an amplifier works when you can feed the amplifier with a repetitive signal from a Function Generator. Or to look at the triangle wave an fixed-frequency PWM SMPS generates under steady conditions...But the big difference is, they are different instruments altogether, a digital storage oscilloscope can do so many more things an analog scope is completely unsuitable for. Especially nowadays almost every beginner wants to do something with an Arduino or similar at some point, and needs to look at UART or SPI or just GPIO. Analog scope is nearly useless for this. So you would need two scopes --except that you won't, because the reverse is only true if very small details are important (and they usually aren't). Even a remotely modern digital storage oscilloscope can replace an analog one in 99.9999% of cases, although maybe it sometimes happens that you do have a really high BW repetitive signal and can't afford to buy an expensive 1GHz digital scope but happen to find a good deal of an used analog top performer. But I doubt it, the best analog scopes have already found their homes.

author: rdl
author_rank: Super Contributor
timestamp: July 29, 2021, 05:00:05 pm
content: I have a Tektronix 2247A and a Rigol DS1052E and I use both. But, unless I actually need some feature only on the digital scope, I use the Tektronix just because the screen is 1000x nicer to look at.

author: TimFox
author_rank: Super Contributor
timestamp: July 29, 2021, 05:21:05 pm
content: To clarify why I like an analog CRO when I don't know what the problem is: Since the analog scope does not periodically sample the waveform, it will show "fuzziness" or similar when an unexpected high-frequency waveform or noise is superimposed on the "regular" stuff. The user can expand the timebase to examine what can't be resolved at the slower time/div. So long as the hf stuff is within the analog bandwidth, it will be visible even if not resolved due to the finite width of the trace on the phosphor face.With a DSO, if you have an unexpected high-frequency waveform, it may show an alias from periodic sampling that can be confusing.An example from the past: the first decent digital oscilloscope we had at work had 100 MHz bandwidth and displayed 10 k points (which was not bad for that time in history). We were tracing down unexpected noise in a complex system and saw a very clean sinusoidal waveform close to 60 Hz, but which did not synchronize to the line. Eventually, we discovered that we were seeing a 10 MHz clock waveform alias at a timebase setting appropriate for 60 Hz: it was the roughly 6 ppm difference in calibration between the external clock and the internal clock of the DSO. (To check for aliases, change the timebase and see if the apparent frequency, in Hz, changes. That was the lesson learned from that episode.)

author: Siwastaja
author_rank: Super Contributor
timestamp: July 29, 2021, 05:31:25 pm
content: Digital scopes come with intensity grading "emulating" what the analog did, but come with a better digital intensity control. This means, if you have one "weird" occurrence every 50 periodic waveforms, you will see it very dimly on an analog scope, but miss that on cheap early digital scopes. A modern digital scope will show it like the analog one.But if you have one weird occurrence every 1000 periodic waveforms, good luck finding a signal that dim on analog screen, swamped by the bright trace of "normal" waveforms. A modern digital oscillosscope with well functioning intensity grading can possibly show even that if you turn the intensity knob.

author: TimFox
author_rank: Super Contributor
timestamp: July 29, 2021, 05:39:28 pm
content: Yes, when you know what you are looking for, the storage capability of the DSO freezing the result is a great advantage.The "quantization" effects (due to finite ADC resolution) should be negligible, but there are still issues with periodic sampling that need to be understood as well as overcome. Modern DSOs have gone a long way to reduce problems due to sampling aliases. If you can set up a trigger that corresponds approximately to your one in a thousand cycles, then the DSO is the only way to catch the result.

author: Trader
author_rank: Frequent Contributor
timestamp: July 29, 2021, 05:49:10 pm
content: I still believe that the people are comparing $ $ $ $ $ DSOs against $ CROs.There is no doubt DSO is the way to go, but most of the time a CRO can do all the work costing a fraction.Yes, microcontrollers use serial communications as UART, SPI, I2C, but this not means the people look at those signals in a MSO, when necessary (rarely), is MUCH better to use a USB Logic Analyzer.99% of the time a Scope is used only to see Signals, that's it and a good $ $ CRO can do a lot comparing to a $ $ $ DSO, and maybe not so much compared to a $ $ $ $ $ DSO.

author: rstofer
author_rank: Super Contributor
timestamp: July 29, 2021, 06:36:57 pm
content: Quote from: Trader on July 29, 2021, 05:49:10 pmNo, it can't. The single shot capture, measurements and decoding are all essential for MCU work and the analog scope doesn't usually have the features or the number of channels. I'm sure they are out there but I have never seen a 4 channel analog scope. Want to watch SPI? Four channels is the way to do it whether it is decoded or not. You absolutely want to sync on the CS' and watch MISO, MOSI and Clk. Can you get by with 2 channels and external trigger? Sure! But it is tiring...I have a Tek 485 and a Rigol DS1054Z and I use the Rigol. Sure, the Tek has more bandwidth when I need it but it provides absolutely NONE of the features of the Rigol. Other than squiggly lines...As to cost? My very used 485 cost about $200 plus shipping, call it $250. For another $100, I can get a brand new 100 MHz 2 Channel Siglent with all of the modern features (that don't require 4 channels). With a warranty! And that isn't even the cheapest equivalent scope around.https://www.amazon.com/Siglent-Technologies-SDS1202X-Oscilloscope-Channels/dp/B06XZML6RDThere just isn't all that much $ savings in buying a decent analog scope over an entry level digital. That mythical $50 analog scope in perfect condition is probably a little rare out in the field.The reason the other thread was closed is that it went off the rails and got personal.

author: TimFox
author_rank: Super Contributor
timestamp: July 29, 2021, 06:52:51 pm
content: I agree with you about single-shot capture and other DSO features, but there are 4-channel analog CROs: any of the plug-in Tektronix 7000 series units can accept two two-channel vertical plug-ins (I have a 7603 which can hold two vertical and one horizontal plug-in).

author: David Hess
author_rank: Super Contributor
timestamp: July 29, 2021, 07:14:13 pm
content: Quote from: Trader on July 29, 2021, 04:09:45 pmThat is almost always an apple to oranges comparison. The analog oscilloscopes involved were almost always priced for a more expensive market than a low end DSO, so the comparison is between an instrument with an inflation adjusted cost of at least $5000 versus a low end DSO costing $1000 or less. Nobody is interested in an analog oscilloscope that originally cost $200 in 1980.Quote from: Siwastaja on July 29, 2021, 05:31:25 pmUnfortunately their intensity grading is always or almost always horridly implemented. It does not duplicate the intensity curve of a CRT, so it cannot be used for tangential measurements, and it does not look nearly as good.

author: Siwastaja
author_rank: Super Contributor
timestamp: July 29, 2021, 07:28:40 pm
content: Quote from: Trader on July 29, 2021, 05:49:10 pmNot really. For exaple Rigol DS1054Z series almost a decade ago totally changed the game IMHO, and others have followed. Yes, the usability kinda sucks and it was buggy, which is always a problem with cheap instruments, but the specs made it (and other similar products) very good replacements for analog scopes even for those special purposes where analog still outperformed cheap digital instruments, and obviously much much more.For almost a decade, a $400 DSO has been able to store megabytes of waveforms, intensity grading, protocol decoding, etc.Single-shot events happen on analog levels, for example power supply trouble shooting in microcontroller circuits and similar. Logic analyzers are of no use for such cases. They are specialized for protocol decoding alone, while a modern (even a cheap) DSO is a true multi-purpose instrument.The key is to understand what these instruments can be used for. Every beginner has some vague idea what a "scope" is used for. If they then listen to bad advice such as Trader's, they think that an analog scope is useful for them, or even better than a cheap DSO. Most often it is not and then they need to buy the DSO anyway to get what they actually needed. Analog scope is a pretty specialized limited use instrument which has its strong points in the right hands, but almost never it is the right solution for a modern beginner of 2000's, especially with limited budget. Maybe it's ok if they are doing audio amplifiers only.

author: bdunham7
author_rank: Super Contributor
timestamp: July 29, 2021, 09:02:09 pm
content: Quote from: David Hess on July 29, 2021, 07:14:13 pmTrue enough. If I ever upgrade to a Siglent SDS 2104X+ I will hack it and do a comparison with the 2465B. I suspect the old Tek will have met its match with only a few minor advantages left.QuoteSome are bad, some newer ones are better but they definitely have a different brightness/repetition rate curve, with the DSO being a lot flatter. That means you can't tell as much by how it looks, but you can spot more infrequent signals. But it is always problematic to judge new technology by how well it replicates old--a decent entry-level DSO these days will have intensitycolorgrading. With some setup care, the feature is very useful. Here's a picture of a pulse that repeats at 20MHz but every millionth pulse has some extra amplitude.

author: bdunham7
author_rank: Super Contributor
timestamp: July 29, 2021, 09:23:36 pm
content: Quote from: Trader on July 29, 2021, 04:09:45 pmThe OP in that post was an idiot and a troll. There's no requirement to tolerate incoherent babbling in a tech forum, although EEVBlog is fairly tolerant of stupidity--a position I agree with, b/t/w. This is the least censored forum that I know of.I'm not sure why you are posting this, but most of what you argue is silly. There are good 500MHz analog scopes for $100-130? Where? And if there were, modern entry-level DSOs have a multitude of useful features beyond what those analog scopes have. You think most DSO users are just looking at a waveform 99% of the time? I don't. Even if that were true, in order to see a waveform you have to trigger on it--and modern entry-level DSOs have advanced trigger features that you just don't find on earlier analog scopes.Oh, and DPO is an advanced version of DSO, it refers to intensity grading. I"m not sure what you are looking at , but decent name-brand 1GHz DPO scopes are still going for a lot more than an entry level 100MHz DSO if they work.

author: james_s
author_rank: Super Contributor
timestamp: July 29, 2021, 10:42:15 pm
content: I love my Tektronix 465B CRO, it's a beautiful instrument, but I would probably not go out and buy one if I didn't have it already. Once I got a good DSO I found I never really used the analog scope anymore, about the only time I pull it out is if I need XY mode or if I'm just feeling nostalgic and want the warm fuzzy feeling of using one. I do like the way an analog scope operates in real time and all of the controls respond instantly, but the single shot and measurement capabilities of a DSO outweigh this in almost all applications. It's hard to make a price comparison because AFAIK nobody makes analog scopes anymore so what is available is the used market and few people want them anymore because decent DSOs have gotten so cheap. For a while it was easy to get a working analog scope for next to nothing, now a lot of those supplies have dried up and they are harder to come by. They are also bulky and heavy so shipping is expensive and risky.

author: John B
author_rank: Frequent Contributor
timestamp: July 29, 2021, 10:49:15 pm
content: CROs seem to have reached collectable status. Every online auction I've seen in years has resulted in competition and greatly inflated prices for what you're getting as a tool.Single shot capture is a must have nowadays.

author: Trader
author_rank: Frequent Contributor
timestamp: July 29, 2021, 11:29:28 pm
content: Quote from: Siwastaja on July 29, 2021, 07:28:40 pmI said: "THERE IS NO DOUBT DSO IS THE WAY TO GO, but most of the time a CRO can do all the work costing a fraction."Is very improbable a beginner will buy a CRO just because of my comment. And I also said: "comparing $ $ $ $ $ DSOs against $ CROs".A LOT of people work with electronics and never had an oscilloscope, mostly in poor countries. I found several times 20MHz to 60MHz CROs for ~$50, and as a hobbyist, I think is a good idea to get a CRO for ~$50 and in the future a DSO for +$350.This is my opinion, nobody will be hurt for spending that little and this scope will Teach a LOT to that begginer.ps.: several CROs has very good trigger functions:

author: Trader
author_rank: Frequent Contributor
timestamp: July 29, 2021, 11:41:26 pm
content: Quote from: bdunham7 on July 29, 2021, 09:23:36 pmI didn't say a so low price, you said that. On AVERAGE a 500Mhz CRO costs 50% of a DPO and 25% to 10% of a DSO.What means AVERAGE? This means, if you look at some big or local marketplaces for a couple of months, eventually someone sell a CTO for a bargain. (it's not so easy, but possible)This is not advice, but I'm very happy with a 100MHz DSO and a 400MHz CRO, if someday I need much more, I'll check the "old" DPOs, of 1GHz for ~$500 instead of a new DSO for +$5,000

author: John B
author_rank: Frequent Contributor
timestamp: July 29, 2021, 11:48:36 pm
content: but most of the time a CRO can do all theworkcosting a fraction.this scope willTeacha LOT to that begginer.Compare "teach" and "work", are they the same outcome? There's a lot of interesting things you can learn by setting up experiments with repetitive signals, ie the "teach" aspect, but will a CRO suffice for a typical modern project where you have to deal with transient signals, digital signals, or compare multiple iterations of a signal? This is where a DSO is a tool for doing work.

author: bdunham7
author_rank: Super Contributor
timestamp: July 29, 2021, 11:56:29 pm
content: Quote from: Trader on July 29, 2021, 11:41:26 pmLeaving aside your peculiar definition of the word "AVERAGE" (does it mean something different in caps???) what '500MHz CRO' are you referring to? Can you show us just one?

author: Trader
author_rank: Frequent Contributor
timestamp: July 30, 2021, 12:10:13 am
content: Quote from: bdunham7 on July 29, 2021, 09:23:36 pmSo, the best way to avoid a post being closed is focus only on the Technical Arguments instead of commenting about other people's posts using terms like: "idiot and a troll", "incoherent babbling", "stupidity", "you argue is silly".Thank you for explaining and also giving an example.

author: Trader
author_rank: Frequent Contributor
timestamp: July 30, 2021, 12:17:37 am
content: Quote from: bdunham7 on July 29, 2021, 11:56:29 pm500 Mhz is just a round number, I know some Teks of 400 Mhz, but I think (my opinion) even a 750 MHz waveform is very acceptable at a Tek 350 Mhz.

author: tggzzz
author_rank: Super Contributor
timestamp: July 30, 2021, 12:31:38 am
content: Quote from: rstofer on July 29, 2021, 06:36:57 pmIf you need to capture, store and processdigitalsignals, then use a tool designed to work in the digital domain. Logic analysers and protocol analysers can be very cheap, much much cheaper thananynew scope.A scope is ananalogue domaintool, and is the best way to seeanaloguesignals, such as the voltages on MISO and the other lines you mention. Once you have ensured those analogue voltages will be correctlyinterpretedasdigital signals, flip to debugging in thedigital domain.

author: tggzzz
author_rank: Super Contributor
timestamp: July 30, 2021, 12:41:07 am
content: Quote from: John B on July 29, 2021, 10:49:15 pmIt isn't that clearcut. Many analogue waveforms can be made repetitive with suitable design strategies - and can therefore be visualised with analogue domain tools with or without storage.Most of the things that benefit from single shot capture aredigital signalswhich are best captured, filtered and processed bydigital domain toolssuch as logic analysers and protocol analysers.I seem to need a digitising scope's single shot capture facility about once every two years. The rest of the time I use digital domain tools.

author: John B
author_rank: Frequent Contributor
timestamp: July 30, 2021, 01:13:59 am
content: My digital domain tools are on my DSO.

author: bdunham7
author_rank: Super Contributor
timestamp: July 30, 2021, 01:20:40 am
content: Quote from: Trader on July 30, 2021, 12:10:13 amI didn't say that. There's nothing wrong with using qualitative terms. However, if you prefer technical terms, the foundation of any technical debate is agreement on the meaning of the terms. If you use the term 'AVERAGE' to mean a rarely found low value, 500MHz to refer to a scope with a -3db point of 350Mhz, etc, it makes it difficult to know exactly what you are saying. I'm still wondering what you think 'DPO' means...and I don't mean just the words behind the acronym.As for the 2465A that can display a signal beyond its specified BW, most scopes will do that if you overdrive them, the limiting factor is usually the trigger. A Rigol DS1054Z can be made to trigger on and display a 400MHz signal, but that doesn't make it a 400MHz scope and isn't all that useful in real life. Not useless, just limited to an occasional crude display of whether a signal is present.

author: bdunham7
author_rank: Super Contributor
timestamp: July 30, 2021, 01:27:09 am
content: Quote from: tggzzz on July 30, 2021, 12:41:07 amTwo examples of when single shot actually solves unusual, non digital problems.1. Uncorrelated signals on multiple channels. Modern DSOs have dropped the 'ALT' trigger function, but a single shot can yield a clear view of uncorrelated multiple channels.2. Noisy or unknown signals that you can't seem to trigger properly on--just slow the timebase down a bit and take a random (or triggered in some cases) single shot and then zoom in and see what is going on. When you see it, it makes it easier to figure out how to trigger on it.

author: Trader
author_rank: Frequent Contributor
timestamp: July 30, 2021, 03:02:29 am
content: Quote from: bdunham7 on July 30, 2021, 01:27:09 amWhat about this?

author: bdunham7
author_rank: Super Contributor
timestamp: July 30, 2021, 03:26:19 am
content: See my earlier reply to David Hess. Those infrequent aberrations are captured quite well by any decent modern DSO, and then usually can be observed separately using advanced trigger techniques. So the 2467B, a very impressiveand expensiveinstrument in its time, can merely show you occasional glimpses of your rogue signals, whereas a proper DSO can display them quite clearly in living color.

author: Trader
author_rank: Frequent Contributor
timestamp: July 30, 2021, 04:47:14 am
content: Quote from: bdunham7 on July 30, 2021, 03:26:19 amDid you see the videos I posted before? ("#11: Tektronix Oscilloscope Triggering controls and their usage" and "Tektronix 2465A oscilloscope demonstration"), that CROs have a lot of triggering and zoom features.Do you know the 80-20 rule? You are highlighting specific situations, but most time (maybe 99%) the Waveform and Amplitude are the most important info to measure, and complex debug are hard even for a professional.A Rigol 1054z can read up to 125MHz inside the -3db and barely anything after that. A CRO with good sensitivity up to 300-500 MHz is not so expensive.I'll repeat one more time, I'm NOT saying that a CRO is better than a DSO (I also prefer a DSO), I'm saying that a Good CRO can do almost all the necessary work for a hobbyist and even a professional, and they cost much less than a DSO of the same bandwidth.

author: bdunham7
author_rank: Super Contributor
timestamp: July 30, 2021, 05:40:30 am
content: Quote from: Trader on July 30, 2021, 04:47:14 amI was able to test my garage door opener at 315MHz with mine, using the FFT function. And I've demonstrated it previously displaying a stable signal at 400MHz. And that's a pretty low-end scope-- sold mine and moved up. Where are you seeing these inexpensive CROs in good working order? I think a good portion of the novices buying these don't even realize that they have problems--I rarely find one that is 100% tip-top, they all seem to need some work. The only reason these might seem cheap (and they don't seem cheap to me these days) is because they are very old and completely depreciated.QuoteI have a small collection of CROs and I routinely repair, calibrate and even sell them. I'm well aware of the triggers, B-sweeps, expansion, etc. The only way you could believe that this would suffice for any advanced use or that a 'good CRO' can do most of what a DSO can is if you have no clue about what the capabilities of even a low-end decent modern DSO are. If you have an old-school cheapo DSO like a DS1052E, then you don't have much of an advanced feature set to compare to. Or perhaps you don't know what other people are looking at with their scopes--one clue for you is that BW isn't usually all that big of a deal. If 200MHz @3dB isn't good enough, it's not all that likely that 350MHz is going to be the answer. With exceptions, of course. If a CRO works for you, great. Don't assume it will work well for most other people, that's not helping them at all.

author: james_s
author_rank: Super Contributor
timestamp: July 30, 2021, 05:55:35 am
content: Quote from: bdunham7 on July 30, 2021, 01:27:09 amI very frequently use single shot to capture things like startup and transient response of power supplies. I also frequently capture and save waveforms for later comparison. It's also not uncommon that I want to look at the analog aspect of a digital signal.

author: Siwastaja
author_rank: Super Contributor
timestamp: July 30, 2021, 08:21:27 am
content: Quote from: james_s on July 30, 2021, 05:55:35 amExactly this, and much more. Power sequencing, RC circuits...Problems with three-stating, pull-up values, speed, interference... Analog levels like current measurements, comparator setpoints. Whatever. Most control aspects in modern electronics are non-repetitive, or irregularly repeating (i.e., not constant frequency) events, and can't be sampled as binary signals either, or doing that loses too much information. So both analog scope and logic analyser are out, often.Logic analyser is more optimal, possibly fast to use, for some large datasets, but if you go the recommended-by-some "buy an analog scope and a cheap logic analyser" way, you very likely find out you need tostillbuy a DSO.A beginner usually does not have unlimited budget and bench space.A modern low-cost DSO can alone and completely replace these three instruments (DSO, analog scope, logic analyser) no problem whatsoever, and to a limited but often quite sufficient extent, also a spectrum analyser. I do exactly that, all the time, both professionally and for hobby, no problem. If I required very large amounts of bus decoding, a logic analyser would be a timesaver, making life a bit easier. A process optimization, really. I can see no use for analog scope at all, it would be "just for fun".You can buy a massive set of different kitchen knives and lie to yourself that now you have "right tool for every job" but as every professional chef and kitchen enthusiast know, a good universal kitchen knife that is kept sharp does most of the jobs and all those specialized ones see no use.I have had all three instruments mentioned at my disposal and I always end up working with the DSO alone.

author: tggzzz
author_rank: Super Contributor
timestamp: July 30, 2021, 09:48:57 am
content: Quote from: bdunham7 on July 30, 2021, 01:20:40 amAmusingly, my Tek485 (nominally 350MHz) will trigger on sine waves >1GHz. The limiting factor appears to be theamplitude, because that has fallen to ~0.2 divisions. Tek made good triggering circuits

author: tggzzz
author_rank: Super Contributor
timestamp: July 30, 2021, 09:50:07 am
content: Quote from: John B on July 30, 2021, 01:13:59 amI can't afford an 8/16/32/64 channel scope

author: tggzzz
author_rank: Super Contributor
timestamp: July 30, 2021, 09:54:18 am
content: Quote from: bdunham7 on July 30, 2021, 01:27:09 amThere are use cases where digitising scopes are very valuable. Anybody that has needed to use an analogue storage scope will be in no doubt of that!Nonetheless, an attitude thatonlydigitising scopes are useful is incorrect. The aphorism in my .sig indicates my views.

author: bdunham7
author_rank: Super Contributor
timestamp: July 30, 2021, 01:48:13 pm
content: Quote from: tggzzz on July 30, 2021, 09:48:57 amMy 485 is as of yet unrestored and has an aberration on the very fastest timebase, so I can't test that. On most scopes if you just keep increasing the input amplitude, you can still get a vertical amplifier response well after the trigger has given up. Perhaps the tunnel diode triggers of the 485 are exceptionally good. Trigger response on sine waves well above the specified bandwidth is not an unusual feature on scopes, but rather a necessity to ensure a stable trigger in normal operation.QuoteOK, then compare scopes to aircraft. Gliders do fly, and certainly build skills like coordination, energy management, etc. If you just want to demonstrate that they can be made to work, you can. However, if you actually need to get somewhere, you select a conventional powered aircraft --unless you happen to live on the edge of a huge cliff overlooking your destination. I can demonstrate the abilities of an analog scope all day long, but when I need to see something there's a 99% chance I'm grabbing a DSO of some sort.

author: Trader
author_rank: Frequent Contributor
timestamp: July 30, 2021, 02:10:55 pm
content: About the Single Shot Capture, yes I totally agree this is big disadvantage of the CROs, solved by the storage scopes.I'm not recommending buying a CRO instead of a DSO, I just think, finding a good ~$50 CRO will help a lot a hobbyist with a restricted budget for a DSO. (but today this is changing with a lot of chinese cheap scopes)As I showed in the previous video ("DSO Oscilloscope vs Analog - When I use which one and why"), some Real-Time events are much better in a CRO and only good in an expensive DSO. So the CROs could be interesting as a 2nd or 3rd option.With an Analog Oscilloscope, some events can be perceptible by the eye, enough to find the problem, other events, using a camera give a pretty nice result.https://www.eevblog.com/forum/beginners/single-sequence-on-analog-scope/msg165889/#msg165889http://www.fadstoobsessions.com/Downloads-Products/Webcam-Oscilloscope.php

author: Trader
author_rank: Frequent Contributor
timestamp: July 30, 2021, 02:20:04 pm
content: This "Output Channel" could be a very interesting feature to add Storage Capability to an Analog Scope.Maybe a device that gets the output signal, Store it, and output as a continuous/repetitive signal (to be injected in the scope's channel 2?).Of course, this is just a thought exercise, this Problem is Already Solved by the DSOs.

author: rstofer
author_rank: Super Contributor
timestamp: July 30, 2021, 02:33:56 pm
content: There's nothing wrong with 2 channel CROs! We used them to get to the Moon back in 1969. But that was a long time ago and we have moved on. We don't use pay phones anymore either.The thing about triggering, whether DSO or CRO, is that it is sometimes necessary to create a hardware signal to trigger the trace. This happens all the time in FPGA work. In fact, when looking at SPI, the first thing we trigger on is CS'. I can't find it at the moment but somewhere around here I have a circuit for detecting the start condition for I2C. Very handy when trying to synch up to the data stream.Not only can we trigger on these conditions but with a DSO we also get to see the signals before the trigger. That is a very powerful feature!

author: Trader
author_rank: Frequent Contributor
timestamp: July 30, 2021, 02:43:34 pm
content: Quote from: Trader on July 30, 2021, 02:20:04 pmThis also reminds me the RAW option, you can get the raw data, send to PC and do a lot of good work, e.g.: in the DS1054Z, the FFT is much better calculated using the PC power processing, you can even calculate a good accurate THD.Be able to use a CRO to get the signal and sending it to a PC (like a USB scope) will be very interesting, since the high quality of some CROs (Teks).https://groups.google.com/g/hermes-lite/c/zpvR1FV1JZw/m/EaDyjHMyCQAJ

author: tggzzz
author_rank: Super Contributor
timestamp: July 30, 2021, 03:35:27 pm
content: Quote from: bdunham7 on July 30, 2021, 01:48:13 pmYes.QuoteOf course, but that completely misses the point. If you don't have skill and imagination, then you need to be rich (and vice versa).(Apart from that, gliders can fly higher than commercial airliners (except Concorde), often fly higher and faster than light aircraft, can travel further than you imagine, and can stay up for longer than their pilots can stay awake. But that is irrelevant to this thread)

author: tggzzz
author_rank: Super Contributor
timestamp: July 30, 2021, 03:39:13 pm
content: Quote from: Trader on July 30, 2021, 02:43:34 pmThat cheap DSO is, I believe, limited to post processing what's on it screen - not everything captured in its memory. Post-processing in the PC removes that problem.As for measuring distortion, the ENOB becomes important.You clearly understand that the art is in knowing the strengths and limitations ofeachof your tools, and using the appropriatecombination. Not everybody grasps that!

author: TimFox
author_rank: Super Contributor
timestamp: July 30, 2021, 03:40:27 pm
content: When using good DSOs at work, I preferred to download the raw data as a .csv file and do my processing and graphing on my office computer. I especially liked the modern DSOs that would load such files onto a USB thumb drive.Even for trivial math processing, I would put the data into Excel, then into "Grapher" (from Golden Software, a high-powered graphic-presentation software package) that allowed me to limit, scale, set axis limits, set axis titles, change point symbols, change line width and color, etc. before inserting the graph into a report.Unfortunately, most analog CROs don't have a useful analog output that could be externally digitized (some do).

author: David Hess
author_rank: Super Contributor
timestamp: July 30, 2021, 03:49:16 pm
content: Quote from: John B on July 29, 2021, 10:49:15 pmI recommended against purchasing analog oscilloscopes even a couple years ago before that was the case. With rare exceptions, the same people who have such a limited budget that a used analog oscilloscope is all that they can afford are also unsuited to recognizing good deals or being able to repair and maintain such an old instrument.As far as collectable status, I suspect something more general is going on because used test equipment of all types has become much rarer and more expensive over the past couple of years.QuoteIt was a must 20 years ago yet somehow we got by, or at least I did, through various clever tricks.Quote from: bdunham7 on July 29, 2021, 09:02:09 pmWhile a DSO should be superior in displaying signal anomalies, this is highly dependent on the specifics; levels of parasitic oscillation or glitching which would be apparently on an analog display can be all but invisible on a DSO. I have run into this problem several times now with 8-bit DSOs, although oddly enough my Tektronix 7854 which is 10-bits and has no index grading at all could see them easily despite being a digitizing oscilloscope rather than a digital storage oscilloscope.That is why I gave an objective test although most people are not aware of its significance. Can a DSO with intensity grading make tangential measurements? No, or at least I have never found one which could.What good would this be? Not all DSOs can apply standard deviation and RMS measurements to every parameter, and tangential measurements are excellent for verifying that the standard deviation or RMS measurement is accurate. When I was testing DSOs to see if they could make accurate standard deviation and RMS measurements of Gaussian noise, tangential measurement on an analog oscilloscope served to verify the signal source to better than 2%. The alternative would have been something like a sampling RMS voltmeter.The DSOs which have problems with this are the ones which make measurements on the display record, because the display processing destroys much of the information contained in the acquisition waveform.

author: bdunham7
author_rank: Super Contributor
timestamp: July 30, 2021, 04:01:43 pm
content: Quote from: tggzzz on July 30, 2021, 03:35:27 pmIt's not irrelevant, it's directly on point. Despite your glider theoretically having all those attributes on a good day, it has almost zero practical applications other than recreation. If I suddenly needed to go to Las Vegas quickly (a 200-mile straight line for me, ~300 mile/4-6 hour drive), I could go to a local airport and get a beat up rental Skyhawk (or a T182 Skylane, perhaps) and reliably be there in under two hours. That's going to be difficult to match with any glider no matter how skilled you may be.Also, I don't know the economics angle very well, but I suspect that gliding is overall a tad more expensive then general aviation, at least here in the US.

author: tggzzz
author_rank: Super Contributor
timestamp: July 30, 2021, 04:03:56 pm
content: Quote from: David Hess on July 30, 2021, 03:49:16 pmI, and I suspect others, would also like to understand that phenomenon.QuoteMake that 42 years, in my case.

author: TimFox
author_rank: Super Contributor
timestamp: July 30, 2021, 04:49:27 pm
content: 50 years ago, we survived by taking Polaroid exposures of single-sweep waveforms. CROs, cameras, and films were rated for "writing speed", in cm/sec, for that purpose.Polaroid film was available with a nominal (not well-controlled) speed of ASA 10,000 for high-speed capture.This was cumbersome, but more reliable than analog storage oscilloscopes.Nostalgia isn't what it used to be...

author: bdunham7
author_rank: Super Contributor
timestamp: July 30, 2021, 05:06:02 pm
content: Quote from: David Hess on July 30, 2021, 03:49:16 pmBy 'tangential measurements' are you referring to tangential noise measurement, similar to this but applied more generally to things other than amplifier input noise?https://w140.com/tekwiki/images/c/c8/Measuring_conventional_oscilloscope_noise_garuts_samuel.pdfI'm not sure why this technique would not work on any DSO, intensity grading or not. It appears to at least nominally work on mine. As for the accuracy of the DSOs built in RMS measurements, there is a significant limitation when measuring input noise because the RMS measurement will include any DC offset, which shows up at very low levels (500uV/div, e.g.) even when AC coupled. At higher levels of Gaussian noise, the RMS and StDEV match what my AWG says they are.

author: tggzzz
author_rank: Super Contributor
timestamp: July 30, 2021, 05:15:34 pm
content: Quote from: bdunham7 on July 30, 2021, 04:01:43 pmThe point I was making is in the sentence you snipped. Maybe you missed it, so here it is again:"Of course, but that completely misses the point. If you don't have skill and imagination, then you need to be rich (and vice versa)."QuoteIn the region of £12/launch, plus £30/hour including instructor. More importantly it isfun, e.g. +3g/-1g and formation flying and aerobatics all before going solo, flying alongside raptors, no falling asleep because flying straight and level is soboring.

author: james_s
author_rank: Super Contributor
timestamp: July 30, 2021, 05:36:13 pm
content: Quote from: tggzzz on July 30, 2021, 04:03:56 pmI have wondered if it is the fact that so much of the electronics industry has moved overseas that all the used gear is in China now, or perhaps it's a generational thing where gear gets replaced in cycles as new waves of technology appear. For a while the market was flooded with stuff like analog scopes and 70s-80s gear as businesses upgraded to DSOs and other 90s-2000's gear. Then there was a wave of that gear as businesses upgraded and now we are at a point where the last round of high end gear that was purchased is still working. Or maybe the pandemic has resulted in enough people taking up hobbies or getting more into the hobbies they have and buying up supplies of gear leading to shortages. Either way it has been well over a year since I've seen anything resembling a deal on any sort of used test equipment I watch for. Thankfully I have just about everything I really need at this point.

author: Trader
author_rank: Frequent Contributor
timestamp: July 30, 2021, 06:37:14 pm
content: Quote from: james_s on July 30, 2021, 05:36:13 pmIf you have (for example) a $350 Rigol DS1054Z 100MHz, you can do almost everything you need as a hobbyist and also do a lot of professional experiments and debugs.To have a 2nd ~$350 "low-end" scope, 200/250Mhz, 2CH won't add so much to you. (my opinion).A ~$1,350 Rigol MSO5074 (hacked to 350MHz) or a ~$1,400 Siglent SDS2104X Plus (hacked to 500MHz) (plus 4*500MHz probes $ $ $) will add much more certainly, a better FFT, etc.On eBay you can find a (for example) 4CH Tektronix 2465A 350MHz for ~$150, and at least, bring more quality to your waveform analysis, since it performs well even at 750MHz.Single-shot capture below 125Mhz, you can use the low-end DSO, for high frequencies waveforms you can use the CRO, and now you have 4 more channels to play, costing 90% Less (I excluded the Keysight and Tek DSOs from the same range, that costs at least 2X the Rigol/Siglent).In summary: I think these CROs fill this gap between $350 and $1,350 scopes, as a 2nd scope.

author: tggzzz
author_rank: Super Contributor
timestamp: July 30, 2021, 07:19:47 pm
content: That's a considered, nuanced, balanced, rational argument.Shame too many people don't think in those terms!

author: bdunham7
author_rank: Super Contributor
timestamp: July 30, 2021, 07:31:56 pm
content: Quote from: Trader on July 30, 2021, 06:37:14 pmIf you can find (or have found) a good condition 2565/A/B for $150 and you have room on the bench and a specific need for its capabilities, then go for it. Most of the ones I've seen for $150 on eBay are broken or even incomplete. I have several (2445, 2465B, 2221A, and more) that I have fixed up and the specific reasons I might drag one out are usually related to vector graphics or a specific need for the Z-axis input. Also, on one occasion I needed something with better input overload recovery, but I also have two other DSOs that would suffice. If I had room to keep one on the bench, I might use it sometimes just because it was there. IMO the gap that an old high-performance CRO would fill is small and waning, but YMMV. What do you use yours for?

author: tggzzz
author_rank: Super Contributor
timestamp: July 30, 2021, 07:53:11 pm
content: Quote from: bdunham7 on July 30, 2021, 07:31:56 pmUndoubtedly many Tek 24x5 and similar machines on fleabay are suspect, and need a little work. But not all.Undoubtedly digitising scopes will be the way of the futureBut...A good working analogue scope is a joy to use and is very capable, and can be used for many purposes.100MHz was fine for digital logic 40 years ago, but modern jellybean logic requires far more than that.Anybody that declares that only digitising scopes should be considered and that working analogue scopes should be ignored is, IMHO, a twit.For most of my purposes, a sufficient combination is a 2 channel >300MHz analogue scope (assure signal integrity), plus cheap logic/protocol analyser and printf statements. If those aren't sufficient then you need serious thought or money.

author: Trader
author_rank: Frequent Contributor
timestamp: July 30, 2021, 08:23:05 pm
content: Quote from: bdunham7 on July 30, 2021, 07:31:56 pmEverything on eBay is suspicious, even a new product. A while ago I bought a "Used" power supply and the seller sent a totally broken device, I returned it, simple.But if the seller is honest, he/she will put real pictures, and inform, as best possible, the device status, etc...Any used scope requires a certain examination and maybe calibration (yearly). A good CRO costing 80% less than a "medium-end" chinese DSO, I think it's a good deal.

author: radiolistener
author_rank: Super Contributor
timestamp: July 30, 2021, 08:26:19 pm
content: Analog and digital oscilloscopes both have pros and cons. So this is just a choice of user.For a noob, it's better to select a new model of digital oscilloscope from a known brand, like Rigol or Siglent.

author: TimFox
author_rank: Super Contributor
timestamp: July 30, 2021, 08:56:46 pm
content: A related question, relevant to new students of the art:In my education, during the previous century, my schools were careful to have us start with traditional equipment (stopwatches, thermocouples with potentiometers, analytic balances, analog voltmeters, etc.) to learn the basics, knowing that when we went on to "real work", we would use more modern equipment, but needed to know what they did (instead of treating them like a black box) and what limitations were important.In that regard, it is easier to understand what a CRO is doing, since you can slow it down to see the trace moving in real time. Going from there to a fashionable DSO, you can then learn how to deal with aliasing, finite resolution, latency, etc. while appreciating the measurement, storage, and mathematical capabilities.

author: Trader
author_rank: Frequent Contributor
timestamp: July 30, 2021, 08:59:40 pm
content: I guess, these are the "cheap" basic and "hackable" scopes from 350MHz to 1GHz.* Rigol MSO5074 # $1,000 (long FFT) # (hack up 350 MHz)* Siglent SDS2104X Plus # $1,400 + 4 new probes (more default features, cheap options, long FFT) # (hack up 500 MHz)* Tektronix MDO34 # >$4,800 # (up to 1GHz, hackable?)* Keysight DSOX3014T # >$4,800 # (up to 1GHz, hackable?)My preference will be a Tektronix or Keysight of 1GHz, but the "basic" model costs $5K. And any scope, if hacked, will void the (3-5 years) warranty...IMHO, as the 2nd scope for a hobbyist that already has some decent DSO and has some budget restriction, could be a good CRO.

author: bdunham7
author_rank: Super Contributor
timestamp: July 30, 2021, 09:35:52 pm
content: Quote from: TimFox on July 30, 2021, 08:56:46 pmI agree totally with the importance of the 'historical' aspect of science and technology, learning why things are done the way they are by learning how they were developed. I also enjoy going back and seeing things that I missed--how and when they were developed, etc. Technoanthropology perhaps. But my interest is in the details, the little tidbits that make up device, as well as the general progression. A DSO seems like a natural evolution of the oscilloscope, but fundamentally it is an entirely different sort of machine. The only reason it strongly resembles an analog oscilloscope is because is because that is the format that users expect to see, from a graticuled screen to knobs for vertical sensitivity and horizontal timebase. Behind the scenes it is an entirely different beast, eliminating many of the issues that older types had while introducing new ones. Understanding things like analog triggers, phosphors, delay lines, etc helps you understand why a DSO is configured the way that it is and in a limited way, how to use one, but that historical understanding actually tells you very little about what it is actually doing inside, nor what it is actually capable of in its best form.

author: TimFox
author_rank: Super Contributor
timestamp: July 30, 2021, 09:42:10 pm
content: This is not only for historical interest, but to give the novice student a feeling for how measurement works and what it means.For example, nobody uses analog voltmeters anymore (although I own a few), since DVMs are more convenient and accurate.However, if a novice starts with a Simpson 260 VOM, he can see a physical needle move and understand the resolution of the measurement (between marks on the dial), and watch it change in quasi-real time.If he starts with a DMM, all he sees is a number pop up--many consider a readout to be inherently perfectly accurate (like on a pocket calculator) because it's digital, innit?Operating a traditional analytic balance manually gives far more insight than the modern digital-readout scales, that again just pop up a number like magic.But, once the student progresses past basic understanding, then on with the modern units and understanding what their capabilities and limitations are.

author: tggzzz
author_rank: Super Contributor
timestamp: July 30, 2021, 09:51:15 pm
content: Quote from: TimFox on July 30, 2021, 08:56:46 pmPrecisely.If you understand the basics, you can apply them to any equipment that will be developed in the future. That's a solid engineering education.If you spend a lot of your time puzzling over a consequence of a setting hidden two levels down in a menu system, you will know how to use that instrument. That is fine for technicians .I was lucky I learned that from Asimov's story " Profession ", available on the web and just as relevant now as in 1957.To avoid misunderstandings, we need both engineers and technicians, of course, just as we need both doctors and nurses.

author: TimFox
author_rank: Super Contributor
timestamp: July 30, 2021, 10:01:45 pm
content: My favorite gadget from that time in my life was the traditional "analytical balance", with two pans and standard weights. I remember the final (least-significant) part of the balancing involved turning a knob that moved the end point of a metal chain to change the balance. A quick Google for "analytical balance" only turned up the modern units (one pan and digital innards), but I found one source in India that still sels the older kind (for roughly $200 USD),https://www.indiamart.com/proddetail/chainomatic-analytical-balance-7916098133.html?pos=1&pla=nAs a youngster, we visited a friend of the family who worked at Lincoln Labs at MIT. I remember the sign on a door: "Balance room. Do not slam door."

author: tggzzz
author_rank: Super Contributor
timestamp: July 30, 2021, 10:14:07 pm
content: My favourite is from school physics lessons, measuring voltage to 0.1% when the best available analogue meters were 2%.Tools: a not very stable NiFe cell, an uncalibrated but sensitive meter, a Weston Standard Cell, a 1m rule and 1m of resistance wire. Plus imagination and understanding, of course.

author: bdunham7
author_rank: Super Contributor
timestamp: July 30, 2021, 10:38:01 pm
content: Quote from: TimFox on July 30, 2021, 09:42:10 pmWhat I'm pointing out is that a DMM operates on an entirely different principle than a Simpson 260 and having 'the basics', or even a thorough understanding of an analog VOM does not inform you as to the internal operation of the core a DMM -- and thus does not give you any insight into its capabilities nor its potential shortcomings. Some fundamentals carry through, from Archimedes to Newton and so on, but others don't. An advanced engineer that specialized in taut-band meters and VTVMs will not have any clues about how a dual-slope ADC might work unless they learn that anew. Of course they would understand precision voltage dividers and amplifiers, so their previous education wouldn't be totally wasted.

author: TimFox
author_rank: Super Contributor
timestamp: July 30, 2021, 10:43:53 pm
content: tggzzz:I remember one of those, a true "potentiometer", where the wire was supplied mounted on a meter stick. 1 mm resolution was 0.1% of full-scale.Here's one, made by Central Scientific Co. of Chicago, now in Constantinople:http://www.hasi.gr/instruments/ele66We also had some of the original-style Wheatstone bridges, where the resistive legs were varied by placing tapered metal pegs into mating sockets between the wire-wound resistors inside the box.

author: TimFox
author_rank: Super Contributor
timestamp: July 30, 2021, 10:45:46 pm
content: Quote from: bdunham7 on July 30, 2021, 10:38:01 pmI'm not referring to learning how to design and build a DMM, I'm referring to measuring voltage as a new concept for the novice student. The guts of a DMM are additional to the guts of a VOM, and should be learned later.

author: tggzzz
author_rank: Super Contributor
timestamp: July 30, 2021, 11:49:48 pm
content: Quote from: TimFox on July 30, 2021, 10:43:53 pmThat's itI suspect the school made their own rather than buy one, though.The other trick at school was to use a sensitive but slowammeterto measurecharge. Understanding the principles behind such ballistic galvanometers neatly ties together the concepts and practical aspects of current, charge, time constants, and integration. Won't get that from a DMM, no matter how many digits it has.The nearest I have to a wheatstone bridge is a 7-decade Kelvin-Varley divider plus a nice stable 9.999571V voltage source. Sounds like the internals of some of the Fluke voltmeters from the 1960sI also have a couple of working saturated Weston cells, one of which dates from 1949

author: james_s
author_rank: Super Contributor
timestamp: July 31, 2021, 02:49:15 am
content: Quote from: tggzzz on July 30, 2021, 07:53:11 pmJust about the *only* reason to consider an analog scope outside of a few specialized niche uses like XY mode is price. If you find a good deal on a *working* one or just want the experience of using one then by all means go for it, they are still useful instruments. The key there is finding a working one that is a good deal, these are getting harder to find all the time and they're only going to keep getting harder to find as time goes on. Nobody is making them anymore and every one that gets worn out, blown up, destroyed in shipping, or otherwise scrapped is one less available for someone to buy. A working >300MHz analog scope is a specialized item, they were always expensive and never all that common, I've never even seen one in the flesh, much less actually owned one. Most people are not suggesting ignoring working analog scopes, but it is not really realistic to assume that most people can just go out and find a good deal on one. It's like suggesting someone go out and buy a 30 year old car, I have one, I love it, it gets me around just fine and I wouldn't trade it for anything, but it's still a 30 year old car, some of the parts are hard to come by these days, and if I didn't know how to work on it myself and didn't enjoy working on cars it would be a hassle. A 30 year old scope is the same way.

author: Trader
author_rank: Frequent Contributor
timestamp: July 31, 2021, 03:34:59 am
content: Quote from: james_s on July 31, 2021, 02:49:15 amI agree, it's not easy, but still possible, these screenshots are just some scopes sold in the last 3 months, there are much more.https://www.eevblog.com/forum/beginners/analog-versus-digital-oscilloscopes-2/msg3617766/#msg3617766If you want a 350-500 MHz scope those are the DSO basic models [70-100 MHz], costing 6X more, and you need to "upgrade it", losing the 3-years warranty.https://www.eevblog.com/forum/beginners/analog-versus-digital-oscilloscopes-2/msg3617782/#msg3617782The Tek 350MHz has an effective bandwidth (-3db) at 430MHz. Image shows 2 equal amplitude signals fed into CHs 1 & 2, 1 at 40MHz, the other 400MHz. On a 400MHz scope it is normal for the 400MHz signal to have 30% less vertical deflection (70.7% of the real amplitude), CH 2 lost ~18% (-1.7db) at 400MHz.

author: bdunham7
author_rank: Super Contributor
timestamp: July 31, 2021, 03:54:35 am
content: Quote from: james_s on July 31, 2021, 02:49:15 amWhile I agree with most of what you said, I have to point out that even XY mode is a questionable issue. Although it doesn't look quite as good as a lower frequency XY display on an analog scope, I can display a 99.999999MHz X and 50MHz Y pattern, see the attachment for a very short video.You can't do that on any analog scope that I've ever seen, certainly not on any with a fixed delay line. Not that I typically find this feature useful...

author: bdunham7
author_rank: Super Contributor
timestamp: July 31, 2021, 04:02:42 am
content: Quote from: Trader on July 31, 2021, 03:34:59 amOf the scopes you listed, the fourth is obviously broken and I think the third is as well, but I couldn't find the auction and the picture shown isn't clear enough. The other three I can't be sure, but I'd give you 50-50 odds at best of getting a properly working scope. And calibration is another story on these.

author: Trader
author_rank: Frequent Contributor
timestamp: July 31, 2021, 05:05:42 am
content: Quote from: bdunham7 on July 31, 2021, 04:02:42 amAs I said: "Everything on eBay is suspicious, even a new product."See the "Sold" scopes, I selected this model, there are many. My opinion is just related to the budget for the 2nd scope, if possible get a better DSO.

author: james_s
author_rank: Super Contributor
timestamp: July 31, 2021, 05:48:08 am
content: Quote from: bdunham7 on July 31, 2021, 03:54:35 amI just know I've tried several different Tektronix DSOs connected to a vector arcade game board and none of them have displayed a usable picture, my 465B on the other hand displays a beautiful sharp image that looks just like it does on a proper vector monitor. Testing vector game boards is definitely a niche application though.

author: james_s
author_rank: Super Contributor
timestamp: July 31, 2021, 05:52:44 am
content: Quote from: Trader on July 31, 2021, 03:34:59 amWarranties are meaningless to me, unless something is DOA it isn't worth the effort to pack it up and ship it in for service. Besides, you can easily undo the hack and the manufacture will never know. I got my 1GHz TDS784C for around $500 and my TDS3000 that I upgraded to 500MHz was about the same price. Today both would probably cost more but they're still modestly priced for what you get. The only downside of the TDS700 is it's a boatanchor, but it's still smaller and lighter than the high end Tek analog mainframes.

author: bdunham7
author_rank: Super Contributor
timestamp: July 31, 2021, 05:56:23 am
content: Quote from: james_s on July 31, 2021, 05:48:08 amYes, any actual vector graphics or anything requiring a Z-axis input, an old Tek is your best friend, almost as good as an actual XY monitor.

author: james_s
author_rank: Super Contributor
timestamp: July 31, 2021, 06:01:46 am
content: Quote from: bdunham7 on July 31, 2021, 05:56:23 amI actually don't even use the Z input most of the time, the deflection amps are fast enough that the line between the objects isn't visible, the only artifact is a dot in the middle of the asteroids.

author: magic
author_rank: Super Contributor
timestamp: July 31, 2021, 07:17:11 am
content: Quote from: tggzzz on July 30, 2021, 11:49:48 pmDid you verify linearity of this fine instrument, though?

author: PA4TIM
author_rank: Super Contributor
timestamp: July 31, 2021, 08:09:16 am
content: I bought a 100 MHz Rigol (>10 years ago, it was the first version) I also have a nice collection analog scopes, even more back then, upto 250 MHz and 1GHz sampling scopes/plugins. I preferred the analog scopes so much more as that crap Rigol that I gave it away to a student. I almost never used it because measurement results were way off and mechanically it sucked even more (knobs falling off, switches that needed to be pressed several times before it worked.Then, a year later, I bought a 350 MHz Hameg. (the first models designed by R&S and fabricated in Europe) And that was the end of using my Analog CROs other then for some very rare cases or just for fun. Replaced it this year with a 300 MHz full featured R&S (4 ch, 2 LA 8 ch pods, protocol decoders, bodeplot, arb generator and pattern generator). OK, it costs a lot more as a 40 year old CRO but the CRO scopes that I have where high end versions and far out of reach of a hobbyist when new. The CRO that you could buy on a hobby budget back then, was not great in quality and performance. Old analog scopes will die sooner or later. I have no problem repairing them (repaired my 7704 several times, the plugins even more) most of the others came in defect (and for free) as long as I can find parts and that can be a double problem for a beginner (no repair skills and no parts) 7000 or 24XX scopes are not very repair friendly. 465 and alike are a lot more repairable.My MSO is a swiss knife, great quality and so much more functions as an analog scope. I have a pristine 100 MHz late Hameg analog scope that has a component tester still above my bench for the rare cases I want a ACRT.I also have 2 LA's (+80 channel Tek and a 16 ch Zero) but bv far the most used is the LA from my MSO's. But I am in the repair business, not a firmware developer. The scope LA is fast, real time and can deal with higher voltages. For decoding the zero is more convenient (it knows +100 protocols)

author: tggzzz
author_rank: Super Contributor
timestamp: July 31, 2021, 10:34:16 am
content: Quote from: james_s on July 31, 2021, 02:49:15 amBasically I agree, except...Too many people on this forumdoexplicitly and unequivocably state that working analogue scopes should be ignored - often in favour of a 1054z! Such people also deny that analogue scopes do have some advantages over low-end digitising scopes, and that analogue scopes' relative simplicity is an advantage for a beginner.

author: tggzzz
author_rank: Super Contributor
timestamp: July 31, 2021, 10:38:43 am
content: Quote from: magic on July 31, 2021, 07:17:11 amWhich do you estimate would be more linear: a 2% moving coil meter or a length of piano wire

author: rsjsouza
author_rank: Super Contributor
timestamp: July 31, 2021, 11:53:24 am
content: Quote from: tggzzz on July 31, 2021, 10:34:16 amThe problem is in the absolutes indeed. The test equipment is what you make of it and analog can still be useful and beat digital in some applications but it certainly beats having "no scope". So many started with just a multimeter and the leap to an oscilloscope immensely enriches the experience and ability to develop oneself in this field. Obviously that an used analog will require spare time and expertise (and frequently another oscilloscope) to buy, repair and maintain an older very high bandwidth "clunker".This topic is not new and many long and winded threads were posted already. The one below is already five years old and in our exchange we were already talking about the use cases and pitfalls of buying and owning older gear.https://www.eevblog.com/forum/testgear/question-about-analog-oscilloscopes-vs-digital-oscilloscopes/msg968187/#msg9681871Another issue is locality: IME the wear and tear of the average used oscilloscope available for sale in certain places/countries tends to be proportional to the average price of test gear in that place. After all, the effort to buy one can be so high that you will use it until it runs aground.

author: magic
author_rank: Super Contributor
timestamp: July 31, 2021, 01:46:05 pm
content: Quote from: tggzzz on July 31, 2021, 10:38:43 amProbably the wire. But even assuming uniform material, just 3% difference in diameter between the two sections is enough to eat 90% of you 0.1% error budget

author: TimFox
author_rank: Super Contributor
timestamp: July 31, 2021, 02:26:00 pm
content: One could test this by assembling two identical units (using wire from the same roll) and measuring the error between them at different points using a galvanometer, were it important.

author: David Hess
author_rank: Super Contributor
timestamp: July 31, 2021, 10:27:18 pm
content: Quote from: bdunham7 on July 30, 2021, 05:06:02 pmThat is right.QuoteIt depends on the display device faithfully reproducing the sum of two probably density functions, which is interesting because as the article you linked shows, it also works on sampling oscilloscopes that do not produce an index graded display.QuoteI am not referring to those errors which do need to be accounted for. The limitation I am referring to comes from measuring the display record *after* it has been processed for the display. This destroys the statistical properties of the signal.Quote from: james_s on July 30, 2021, 05:36:13 pmI think it simply took that long for a majority of the existing old test equipment to get sold through Ebay.Quote from: Trader on July 30, 2021, 08:23:05 pmEven if an analog oscilloscope offered on Ebay is not suspicious, shipping can render it suspicious. One of my Tektronix 7834s has a CRT which was likely damaged in shipping.

author: james_s
author_rank: Super Contributor
timestamp: July 31, 2021, 11:43:44 pm
content: Quote from: David Hess on July 31, 2021, 10:27:18 pmThere should always be old test equipment though, companies are making new equipment constantly and as time marches on that equipment becomes old and in theory should end up on the surplus market. It may come in waves as new technology appears but I still would have thought there would be a steady supply.

author: Trader
author_rank: Frequent Contributor
timestamp: August 01, 2021, 01:50:12 am
content: Quote from: james_s on July 31, 2021, 11:43:44 pmExactly, a newly released device started to become old the next day.Just a fun fact, a high-end scope released in the 80s, early-90s, discounting the US inflation, is costing around 1% of the launch price, and a high-end scope today, costs roughly the same*.* based on this info: "1990: $13,045 (2467B) = $24,400 equivalent in 2017" (https://w140.com/tekwiki/wiki/2465B)

author: David Hess
author_rank: Super Contributor
timestamp: August 01, 2021, 09:05:27 am
content: Quote from: Trader on August 01, 2021, 01:50:12 amBut more and more used test equipment produced since the 1990s just becomes trash because it is unrepairable and unmaintainable due to lack of service documentation.

author: Kleinstein
author_rank: Super Contributor
timestamp: August 01, 2021, 09:27:32 am
content: It is not just the lack of service manuals that make the repair of newer test instruments difficult. The tend to use FPGAs / CPLDs with fine pitch. So soldering and measurements can be difficult and without the programmit does not help to replace the chip.The modern electronics got quite reliable, but if it fails a repair is difficult.In the old days failure was more common and parts were build for repairs - at least many instruments and especially higher cost ones.Building for easy repairs adds to the costs and this may no longer be worth it. Especially for professional use a less reliable repaired instrument is not a good thing.There seem to be not many good analog scopes left - at least the offers at ebay are often crap or broken or at least sold as defect to avoid returns. Occasionall there may be a good catch, but that is rare. So an analog scope is increasingly less of a realistic option.There was a time they build combined analog and digital scopes, but this time is gone since the digital part got better and use of LCD screens.

author: gf
author_rank: Super Contributor
timestamp: August 01, 2021, 09:53:55 am
content: Quote from: Kleinstein on August 01, 2021, 09:27:32 amOr even deliberately cannibalized (e.g. many/all valves missing), and then sold as defect (w/o specifying what the "defect" is).Occasionally I see tested/restored units from trusted professional sellers, but then they quickly become expensive, too (say €500+ for a Tek 2465 in working condition).But everything else is IMO rather a lottery, unless you get the opportuinity to test it before buying. It can be a bargain, but it also can be a total loss of investment at the end.

author: nfmax
author_rank: Super Contributor
timestamp: August 01, 2021, 10:02:03 am
content: Quote from: Kleinstein on August 01, 2021, 09:27:32 amThis change happened a bit earlier, IMHO, when CRT oscilloscopes started using cutom ICs and hybrids. Older CRT scopes are more repairable, but more likely to be broken. At the low end, the Hameg CRT oscilloscopes are made with standard parts - but even things like dual JFETs are difficult to find these days.A CRT scope is getting to be a bit like a vintage steam engine - it can certainly 'work', but it's a labour of love (and a money pit) for an expert to keep it in working order. My advice to new electronics hobbyists, and certainly to students, is to forget that CRT scopes ever existed, except as a historical curiosity

author: RoGeorge
author_rank: Super Contributor
timestamp: August 01, 2021, 12:01:56 pm
content: Quote from: james_s on July 31, 2021, 11:43:44 pmI wouldn't count on that, and I'll guess the availability will be less in the future:- instruments are not build like tanks any more, nobody designs lab instruments with survivability to a nuke attack in mind- less repairable because of the lack of documentation and because of the lack of software/configuration tools- we don't know yet how reliable will be a flash memory in 50 years from now, or a FRAM chip (that has a limited number of reads, too, so it will wear out simply by running)- since the frenziness of data leakage there is a tendency from big companies to simply destroy the old instruments just to be sure no password or project info will leave the company together with the old instrument- there is a fashion to recycle old objects at all cost, even when the old object still has users and usage- big manufacturers of instruments realized their old instruments are competing over their own market of cheaper instruments- there is a tendency to put unique IDs inside chips, to encrypt the firmware, to link everything with a call home or a unique registration, therefore re-flashing a modern instrument is almost impossible without software tools specific to that line of instruments and specific to that companyTherefore I'll say the abundance of instruments that are affordable, second-hand, but still gorgeous in performance (the kind of boat anchors we see today on ebay) is a unique feature of our times, something that was caused by the cold war era combined with a very specific level of technology.The instruments back then were seen as standalone and self-contained objects. Now it is not like that any more. Now the tendency is to have a box with no screen and no buttons, box that is usually controlled remotely by a computer. So now the instrument-box suddenly will need a very complex environment around it, an external computer, with external software, and external operating system, and an external network to transfer data, and so on.Good luck restoring and activating a Windows 10 in the year 2070, so to re-flash or simply to use that cool Tektronix spectrum analyzer box-instrument from 2020, with no buttons and no indicators on it!With the current trend, I see everything will be closed and locked-down and encrypted, first to a certain brand and environment, and very soon (as in a few decades away from now) we will see everything (everything as in objects, services, etc.), even your faithful DMM or your faithful handgun, everything will require a personally encrypted key and a valid personally authorization, or else that object/service won't be available to you.This will happen whether we like it or not, simply because the actual level of technology allows to have that.

author: Trader
author_rank: Frequent Contributor
timestamp: August 01, 2021, 02:49:41 pm
content: Quote from: RoGeorge on August 01, 2021, 12:01:56 pmIMHO, this is a real threat to electronics at all, basically, the future will be just buy, use, dispose of.In the past, I was really considered buying the "121GW DMM", just because I thought it was an open-source project. (https://www.eevblog.com/forum/testgear/121gw-why-no-open-source/)Is there a project for an open-source scope (https://www.eevblog.com/forum/testgear/a-high-performance-open-source-oscilloscope-development-log-future-ideas/?all)I'll really consider buying it instead of the best brands, just to support this project and see it improve even more.

author: AaronLee
author_rank: Regular Contributor
timestamp: August 01, 2021, 04:13:34 pm
content: Quote from: Trader on August 01, 2021, 02:49:41 pmAfter reading the post just before yours (RoGeorge's post that you were responding to), I thought to myself how open-source hardware would affect things. Then reading your post, was surprised that already it's being seriously considered.Most large companies / high-end professionals likely won't be interested in open-source hardware, but certainly hobbyists and semi-professionals would if it meant a big savings and/or equipment that would last much longer due to the public-source nature and being able to fix, maintain, and perhaps even upgrade it easily.As time goes by, open-source (not just test equipment hardware, but all sorts of open-source projects) become more and more advanced, and the difference between A-level mass produced stuff and the open-source alternatives becomes less and less. Take scopes, for instance. I doubt many engineers would have the expertise to design a scope at the same level as one of the A-level companies could. Even though an engineer may be expert in one particular area that applies to designing a scope, most likely they aren't in all areas. The engineers that are expert in all areas are likely working for a scope manufacturer. But in time that information leaks out, and becomes more general knowledge, and it starts to make open-source practical and good enough to be in the same ball-park as professional lower-end gear. And even if you don't have one engineer doing the whole things, you get enough well-qualified engineers willing to donate their time to an open-source project, and you still have a shot at getting it right.Add on things like 3-D printing, where in some cases you don't need to mass produce the housing, being producing molds for the housing alone can cost a very large amount. Or some hobbyists might not care, and be able to just take some off-the-shelf case to make a scope. Especially if the scope was in two parts, whereby a PC is used as the screen, and a generic box with knobs and such. (Unlike a typical USB scope which lacks the physical controls of a bench scope). Anyways, that's just a thought off the top of my head, and maybe there's some big issues that would make it impractical. The point is, I think open-source is only going to grow in the future, and grow at a much faster rate, and it's inevitable in my mind that really practical and good open-source test equipment will be on option someday.

author: james_s
author_rank: Super Contributor
timestamp: August 01, 2021, 05:19:04 pm
content: There was at least one impressive attempt at an open source DSO, but the problem is that it doesn't result in savings. IIRC it was projected to cost as much or more than a comparable commercial offering, and that's before you factor in the time and effort to build the thing and figure out some sort of enclosure for it. In the end it only appeals to people who are either charitable and idealistic enough to want to support an open source project for the sake of being open source, or the very tiny minority who have the skills and motivation to get deep into the code and customize it to suit their needs. Personally I thought it was interesting from the standpoint of seeing how a modern DSO works, but I'm not going to pay more for something I have to build myself and then rely on community support for when I can go out and buy a perfectly usable scope for under $500 that comes in a nice molded housing with a carrying handle and professional support if I have a problem with it.

author: Trader
author_rank: Frequent Contributor
timestamp: August 01, 2021, 06:27:46 pm
content: Quote from: AaronLee on August 01, 2021, 04:13:34 pmQuote from: james_s on August 01, 2021, 05:19:04 pmI want to highlight 2 successful open-source projects that still improving more and more:1) NanoVNA (Vector Network Analyzer) (https://nanorfe.com/nanovna-v2.html). A few years ago, a similar VNA could cost a Lot, now it's ~$50. Alan (w2aew) and Joe Smith did excellent videos about its awesome capabilities.2) DSP Receiving Radios - the Si4732/35, and PU2CLR library (https://github.com/pu2clr/SI4735) allows you to build an excellent DSP radio. (https://www.facebook.com/groups/532613604253401/)I also know about some people building an open-source Spectrum Analyzer, very promising.I think this success is because the Chinese companies got the NanoVNA and PU2CRL libraries, created the hardware, and released new Mass Products for a cheap price.When this open-source DSO achieve very good capability, I'm sure some Asian company will manufacture and commercialize it for a competitive price (like the NanoVNA).The DSOs will be like PCs, you can buy good hardware (and upgrade CPU, Memory, Disk, etc), and install/update the new OS distribution version (like Linux flavors) but with All Options opened (Mpts, MSO, FFT, PWR, AWG, Serial Decode, etc), no need to hack it, and people could contribute developing more plug-ins/add-ons, like THD measure, statistical graphics, etc.Maybe the best the big brands can do right now to keep the big market share is, at least, allowing people to develop apps to be installed in their DSOs.

author: AaronLee
author_rank: Regular Contributor
timestamp: August 01, 2021, 09:58:37 pm
content: Quote from: Trader on August 01, 2021, 06:27:46 pmYes, and for some people, having the software being open-source as well will allow them to modify it for their particular needs. There's probably lots of new ways the equipment can be used or used much more efficiently in existing ways, if the users are just allowed access to the software. But the big brands don't have the resources to tailor their products to each and every need. Only they tailor it to mainstream needs where they can sell a lot of units to pay for their development costs. As the number of niche applications are expanded via open source, the number of protentional users also expands, making open source able to take a bigger piece of the total pie.

author: TimFox
author_rank: Super Contributor
timestamp: August 01, 2021, 10:06:40 pm
content: Another related question: Before I retired, my employer purchased some expensive test equipment that ran Windows XP internally. Did Agilent/Keysight upgrade the OS thereafter?

author: David Hess
author_rank: Super Contributor
timestamp: August 01, 2021, 11:43:13 pm
content: Quote from: Kleinstein on August 01, 2021, 09:27:32 amQuote from: nfmax on August 01, 2021, 10:02:03 amI disagree for two reasons:With some very specific exceptions like the improperly mounted hybrids in the Tektronix 2400 series analog oscilloscopes and Mostek ROMs, the custom ICs and hybrids, and this extends to programmable logic now, are more reliable than other parts and tend to not be what fails.The most common parts to fail tend to be commonly available ones. Most of the repairs that I do are for bad or worn out capacitors, mechanical failure including those edge wipe sockets from Texas Instruments, and failure in jelly bean semiconductors.

author: james_s
author_rank: Super Contributor
timestamp: August 02, 2021, 05:07:00 am
content: Quote from: TimFox on August 01, 2021, 10:06:40 pmI seriously doubt it. I've got two medical vital signs monitors on the bench right now, both are embedded PCs, one of which runs XP embedded and the other Win7. They are treated as appliances by the manufacture, they do not get upgraded. Once the OS is out of support the device is out of support, and these are machines that cost $10k to replace.

author: AaronLee
author_rank: Regular Contributor
timestamp: August 02, 2021, 06:27:45 am
content: I cringe whenever I see professional, high-end equipment running on any version of Windows, and subject to the blue screen of death. The same goes for the typical other alternatives of Linux, which I don't consider to be any more robust. And adding the word "embedded" to the front of the OS doesn't seem to make it any more stable. Why can't these vendors invest in a truly stable OS for their high-end gear?If the system contains NAND flash to hold the program code, it's bound to fail sooner or later. NAND flash by it's nature will fail eventually, even if it's not being written to. Just reading it causes wear. Writing (which involves erasing) causes a lot more wear. Often times a BSP is cobbled together which doesn't take into account the extreme importance of a robust wear-leveling algorithm for NAND. Nor do most firmware engineers realize the importance of making their code to limit writing to NAND more then necessary and using strategies to limit erasures. Many years ago the company I worked for got burned by adopting a BSP for Windows CE which had a poorly designed NAND flash driver. Just like clockwork, the systems began failing about a year after installation, and they all failed within the next 6 months. It cost my company a ton of money to settle the claim. After that, we paid a bit more in order to use Micron eMMC. It's still bound to fail eventually, but with well designed firmware and assuming they got the built-in wear leveling right, it should be a long time in the future, well beyond the warrantee period.These days, you really can't get around buying gear that doesn't have NAND or eMMC. Occasionally you might get something with NOR flash, but even that's going to fail eventually. It's just the nature of the beast. And if the flash fails, you need to have access to an image of the flash to burn it onto a new chip to replace the damaged one, or your gear just became a boat anchor. At least with the common stuff, there should be enough techies around that someone will have a flash image and willing to send you a copy. If it's not common gear, you'd better learn how to make a backup image yourself.

author: RoGeorge
author_rank: Super Contributor
timestamp: August 02, 2021, 08:15:43 am
content: Quote from: AaronLee on August 02, 2021, 06:27:45 amI'm afraid making your own backup from a working device is already not possible.For example, microcontrollers nowadays have internal flash that can be read-protected, so an attempt to read from such a protected chip will return only 0xFF. Even the humble Arduino Uno (ATmega328) can be read-protected. Same for FPGA's with internal flash (e.g. Intel/Altera MAX10 series). And when the flash is external, then the data can be encrypted so a data sniff during boot won't help much either, unless the encryption can be defeated.

author: AaronLee
author_rank: Regular Contributor
timestamp: August 02, 2021, 09:12:36 am
content: Quote from: RoGeorge on August 02, 2021, 08:15:43 amYes, if they've protected it, you might already be out of luck, unless someone's hacked it.

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: August 02, 2021, 09:46:45 am
content: Quote from: TimFox on August 01, 2021, 10:06:40 pmWe have a 1 million USD 32 channel Keysight parallel-bit-error-rate-tester at work that is out of support for the simple reason that MS stopped providing security packages for XP.

author: Trader
author_rank: Frequent Contributor
timestamp: August 02, 2021, 11:53:42 am
content: Quote from: TheUnnamedNewbie on August 02, 2021, 09:46:45 amBig brands (Keysight, Tektronix, Fluke, LeCroy, R&S, NI, etc) are losing market to new low-cost players, and this will accelerate this process.The Super-Computers and Web-Servers market is dominated by Linux, maybe in a couple of years, with the first Open-Source/Hardware DSO and a strong community developing all kinds of plugins and features, with customization, the big PC manufactures will enter the instruments segment.

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: August 02, 2021, 12:28:24 pm
content: Quote from: AaronLee on August 02, 2021, 06:27:45 amWhile I understand the frustration about the OS'es, it kinda makes sense in some applications like high-end scopes. On our UXR scopes we also run other software, like Keysight VSA, Matlab, Python, etc. That needs something like Windows to support it. I've never had one of the Z-series or UXR scopes crash on us in the 5 years I'm working with them. For us, having a 'custom' OS would actually be less prefered over Windows - having Windows in the background makes a lot of things easier, as the same programs we run in simulations on our design computers can be run on the scope/VNA

author: rsjsouza
author_rank: Super Contributor
timestamp: August 02, 2021, 01:54:38 pm
content: Quote from: AaronLee on August 02, 2021, 06:27:45 amI fully agree with the misuse of the word "embedded" and there are many alternatives for real-time OSes (QNX, Nucleos, VxWorks, etc.), but I suspect the pressure to reduce development time is way too big. Not only windows OS has a larger application/coder base with resources everywhere around the internet, true experts on application development on these niche OSes are much more rare.

author: bdunham7
author_rank: Super Contributor
timestamp: August 02, 2021, 02:03:02 pm
content: Quote from: Trader on August 02, 2021, 11:53:42 amAre they? In what market segments?

author: Trader
author_rank: Frequent Contributor
timestamp: August 02, 2021, 03:19:50 pm
content: Quote from: bdunham7 on August 02, 2021, 02:03:02 pmIn all market segments where a non-big-brand device is being purchased.https://www.marketwatch.com/press-release/digital-oscilloscope-market-growth-2021-cagr-value-business-opportunities-top-key-players-industry-share-size-major-manufacturers-and-driving-factors-with-covid-19-impact-till-2027-2021-06-19

author: bdunham7
author_rank: Super Contributor
timestamp: August 02, 2021, 03:31:50 pm
content: Quote from: Trader on August 02, 2021, 03:19:50 pmHuh? That's what I would call a non-answer.That link is to an abstract or advertisement, not the article. It has little to no actual information, other than to apparently list the top 4 DSO manufacturers as Tektronix, Keysight, LeCroy, and Rohde and Schwarz. It also incorrectly states that Tektronix is a subsidiary of Danaher--that's no longer true--leading me to wonder how good the rest of it is. Did you get or read the actual article? If so, what did it say? I would guess that the big brands are not selling products in the low cost market where they have no products (and never have) and aren't attempting to compete.

author: Trader
author_rank: Frequent Contributor
timestamp: August 02, 2021, 04:37:28 pm
content: Quote from: bdunham7 on August 02, 2021, 02:03:02 pmQuote from: bdunham7 on August 02, 2021, 03:31:50 pmA while ago, very few people considered buying a scope other from a big brand.A few years ago, the low-cost chinese scopes (as Rigol or Siglent) are the bestsellers for the Entry Scope market (even in American Colleges and Companies).The low-cost scope profits feed the R&D for mid-range and high-end scopes. It's clear to see a trend, soon the big brands will be surpassed in all devices (PSU, AWG, DSO, SA, DMM, etc) and segments (low <200MHz, mid <1.5GHz, high >1.5GHz).IMHO, the FIRST manufacturer to release the Hardware Design and the Code in a "GPLv3" license, and support the community to improve it, will "Dominate" (conquer the passion) from the Open-Source Communities and Crowdsourcing Market.AFAIK, there is no market for Developing APPs for Instruments and today All bench instruments have firmware and options, think about how much customization could be done for every single instrument (to show more information, to do more tasks, new features and statistics graphics, etc), this would be a good reason to replace the current device to a "Smart"(PSU, AWG, DSO, SA, DMM) like the SmartPhones replaced a lot of devices (including the Phone).The manufacturer could be concerned just to Make the Hardware and selling services, like an App Certification (similar to Google Play or App Store).An inspiration maybe could be Tesla that opened all the patents and is free to use any improvements made to its technology by another party.https://www.vennershipley.co.uk/insights-events/does-teslas-open-source-patent-philosophy-mean-they-are-free-to-use/https://electrek.co/2015/11/10/a-number-of-companies-are-now-using-teslas-open-source-patents-and-it-has-some-interesting-implications/IMHO, Keysight could do that with the "Keysight Smart Bench Essential instruments".

author: bdunham7
author_rank: Super Contributor
timestamp: August 02, 2021, 05:24:23 pm
content: Quote from: Trader on August 02, 2021, 04:37:28 pmWell that one is wrong. There have been low-cost second and third tier oscilloscopes for many decades--from manufacturers like BK Precision, GW Instek, Hitachi, Kikusiui and a variety of house brands. 'Big brand' scopes like the ones that are a few hundred bucks on eBay now were just as unaffordable to the average Joe then as a decent Tek scope is today.QuotePerhaps your behind-the-paywall article would have that info, but I don't know. And schools have been buying lower-cost scopes for years--BK Precision, for example--so unless you have numbers, I wouldn't assume anything.QuoteThey do seem to be nipping at the heels of the big dogs, but IMO they still aren't really competitive with anything but the lowest tiers of the A-brand offerings. And unless they whip their support and service into the proper condition for dealing with the types of clients the A-brands cater to, they aren't going to surpass anyone anytime soon.QuoteYeah, sure. Open source has been around quite a while, so show me a market segment anywhere where open source 'dominates', especially anything that is hardware based. The main issue is that there's no money in it, so everyone who wants to make money and is able to do something else does something else.

author: Trader
author_rank: Frequent Contributor
timestamp: August 02, 2021, 06:29:55 pm
content: WRONG - You are confusing low-cost with low-quality, when comparing "BK Precision, GW Instek, Hitachi, Kikusiui" VS chinese devices during that Same period, just a few years ago the chinese devices achieved a minimum entry-level quality.WRONG - your perception is that chinese instruments aren't dominating in the entry-level market? ok, just google "best oscilloscopes", LOL.QuoteWRONG - they are Very Competitive in Making Hundreds of Millions, and reinvesting on R&D. Try think out the box... A Ferrari is much better than a Toyota (IMHO), but Toyota make Much, Much More Money than Ferrari. I don't think Toyota wants to make supercars, but I'm sure Rigol and Siglent want to do top high-end instruments, and soon they will start "nipping the BALLS of the big dogs".QuoteAndroid, Red Hat, All Super-Computers OS, Majority of WebServers, movie effects, and many open-source applications in every field, I'm sure your Browser is Open-Source.

author: David Hess
author_rank: Super Contributor
timestamp: August 02, 2021, 06:51:32 pm
content: In the past test instruments were divided into separate markets of service instruments and laboratory instruments. The low tier manufacturers provided service instruments and the high tier ones laboratory instruments. Some companies like Tektronix tried to provide both in separate product lines. (1) The various newer companies like Rigol and Siglent may have started providing low end instruments only really suited for service work but now bridge that divide with their high end instruments.With repairability getting worse, the service category does not have as much meaning as it used to these days and low end test instruments are just that, but I think what has changed is that depreciation of technology has made them cheaper to manufacture so there is a larger market exclusive of the diminishing service market to support them.(1) Examples of Tektronix "service" product lines include the T900 series, 22xx series, and 3-bay 7000 mainframes. In that last case, notice that only the 7B53A timebase intended for the 3-bay mainframes included optional TV sync triggering.

author: Trader
author_rank: Frequent Contributor
timestamp: August 02, 2021, 06:56:29 pm
content: Another important effect: who starts using a specific brand, tends to buy (other devices/models) and also recommends to others the Same brand.FMPOV an entry-level market is very important even for lab-grade manufacturers.

author: bdunham7
author_rank: Super Contributor
timestamp: August 02, 2021, 07:48:20 pm
content: Quote from: Trader on August 02, 2021, 06:29:55 pmI'm not even going to try to respond to the rest of your incoherent ramblings, but the whole point of what I said is that there has been an 'entry level' market for oscilloscopes and other test equipment for a very long time and none of the players in that market have gone on to become an A-brand leader. The A-brands don't really compete in this area and they never have. Where did I say that Chinese instruments weren't dominating the current entry-level market? I'm well aware that they are and I don't think that gives them a clear path to join HPAK/Tek/R&S/LeCroy anytime soon. "Making hundreds of millions"--where do you get your facts?

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: August 02, 2021, 07:55:11 pm
content: Quote from: bdunham7 on August 02, 2021, 07:48:20 pmI'm with you on this one. Our lab keeps buying some of the Rigol and siglent entry level equipment now and then, and every time we get one, and then decided that it's just inferior to the ones by the A brands and nobody uses it. None of the big labs I've gone to used anything but the big names (Keysight, R&S, Tek, Yokogawa, Anritsu...).It's all about service. The fact that we regularly get asked by R&S to provide questions we have which they will then have their engineers put into a presentation and come explain us. The fact that Keysight sent a applications engineer when we struggeled with their equalization software package, free of charge, within a week.

author: james_s
author_rank: Super Contributor
timestamp: August 02, 2021, 08:08:17 pm
content: That's certainly no surprise. The entry level gear is a very good value, it offers a lot of bang for the buck and it is affordable to the hobbyist or pro-sumer who is probably not going to spend thousands or tens of thousands of dollars on high end gear. It is obviously not as good as the expensive stuff and it doesn't try to be, the thing it focuses on is being affordable. Getting a reputation for making decent affordable entry level gear is not beneficial to entering the high end market. Bugatti, Ferarri, Porsche, Mercedes and others don't try to complete on the low end by making basic economy subcompact cars. Companies like Kia make a pretty good product in terms of a reliable and affordable transportation appliance but they are not likely to start building high end supercars, and if they did I would bet they would come up with a separate brand for that line.

author: nfmax
author_rank: Super Contributor
timestamp: August 02, 2021, 08:25:06 pm
content: Quote from: james_s on August 02, 2021, 08:08:17 pmThis. And indeed, especially compared with old 'service' type CRT oscilloscopes, affordable, entry level DSOs offer spectacularly good value for money. It's a whole different world now!

author: bdunham7
author_rank: Super Contributor
timestamp: August 02, 2021, 09:05:14 pm
content: Quote from: David Hess on August 02, 2021, 06:51:32 pmService and entry-level aren't the same thing, IMO, although perhaps they overlap at the lower end. Entry level and educational instruments have always occupied a level below 'service', or at least the better tiers of service. Something like a Tek 2235 was clearly a service-oriented scope, but certainly not entry-level priced. (something like $2K in the '80s) There were low-end 10 and 20 MHz models that were the market equivalent of a Rigol DS1054Z. It might appear that the new entry-level makers have encroached on the service market, but that's only because the stuff that is getting fixed is often pretty old so relatively low performance scopes suffice. Instruments intended to service modern high-speed electronics do exist, but that level of equipment is still well beyond the hobbyist price point.I don't know the current state of the marketplace, but from my perspective the TOTL Rigol and Siglent technology is only competitive on a 'bang-for-buck' basis or with decades old used instruments. And assembling an instrument with COTS components doesn't make you technologically advanced. I'm not knocking their products, but they are nowhere near cutting-edge technology except in the cost-optimization arena. And while that is great for the bang-for-buck enthusiast who gets a boatload of features and performance for a relative pittance, I think the idea that they will soon surpass the A-brands is silly. They've only recently come up to the level of the two-decades old TDS5104, if that.

author: RoGeorge
author_rank: Super Contributor
timestamp: August 03, 2021, 08:26:45 am
content: Quote from: RoGeorge on August 01, 2021, 12:01:56 pm... 2 days later ...https://hackaday.com/2021/08/02/home-depot-is-selling-power-tools-that-require-activation-in-store/Oh well, I didn't mean itthatfast, though!

author: magic
author_rank: Super Contributor
timestamp: August 03, 2021, 08:43:23 am
content: So far limited to 3rd world countries struggling with 3rd wold problems; still no pay per use

author: RoGeorge
author_rank: Super Contributor
timestamp: August 03, 2021, 08:57:35 am
content: Quote from: magic on August 03, 2021, 08:43:23 amLiterallypay per screw!

author: james_s
author_rank: Super Contributor
timestamp: August 03, 2021, 09:46:38 pm
content: Quote from: RoGeorge on August 03, 2021, 08:26:45 amIt's perfectly reasonable given the massive losses from shoplifting and from what I gather losses have increased sharply. This is not some kind of rental thing, the tool is activated at the time of purchase and then it's yours forever. As long as you don't buy stolen tools it should not be a problem. I'm also fairly sure a determined person could bypass the protection but the sort of people who make a living selling stolen power tools might not want to bother with that.I can't help thinking it would be more effective to simply keep the stock of valuable items locked up and use the business model where you grab a tag off the shelf, take it to the checkout counter and pay, then they give you the item you purchased. They could streamline it and use an automated conveyor to deliver to the checkout stand. Or just embed anti-theft tags inside the tools at the factory, I've seen things that had that.

author: TimFox
author_rank: Super Contributor
timestamp: August 03, 2021, 10:45:57 pm
content: When CDs were new and easy to shoplift, it was common to bring the “jewel case” to the checkout where they inserted the disc from stock behind the counter, whereafter it was your property. Same thing.

author: rstofer
author_rank: Super Contributor
timestamp: August 04, 2021, 05:57:06 pm
content: Our local GameStop still has just empty cases on the shelves. The DVDs are behind the counter. I expect this is common practice in the gaming industry.

author: TimFox
author_rank: Super Contributor
timestamp: August 04, 2021, 06:29:22 pm
content: Out of curiosity: do the gaming DVDs have a finite time period for operation after purchase?

author: David Hess
author_rank: Super Contributor
timestamp: August 04, 2021, 07:35:44 pm
content: Quote from: TimFox on August 04, 2021, 06:29:22 pmSome do if they rely on online game servers, authentication servers, or patch servers.

author: rdl
author_rank: Super Contributor
timestamp: August 05, 2021, 06:23:51 am
content: There was a chain of department stores called Service Merchandise that did things that way. There was only one of anything on display, you took a tag if you wanted to buy, paid at the cash register, then went to wait for your item to come down the conveyor. They're apparently not around anymore. I used to buy a lot of stuff there.

author: David Hess
author_rank: Super Contributor
timestamp: August 05, 2021, 03:23:49 pm
content: Best Productsalso worked that way with stores that were mostly showrooms.

author: tautech
author_rank: Super Contributor
timestamp: August 06, 2021, 09:28:01 pm
content: Quote from: TimFox on August 03, 2021, 10:45:57 pmShit I'm old enough to remember music shops doing that with LP's !

author: Gyro
author_rank: Super Contributor
timestamp: August 06, 2021, 10:06:51 pm
content: Quote from: tautech on August 06, 2021, 09:28:01 pmI'm old enough to have been pulling the LPs out of the file and populating the sleeves when I sold them in my Saturday job!

author: free_electron
author_rank: Super Contributor
timestamp: August 06, 2021, 10:14:09 pm
content: Isn't this a bit of a moot discussion ? Where can you still buy NEW analog scopes ? None of the traditional equipment makers still has em. And if you can still find one it'll be a single beam chopped chinese 20MHz 'blechtrommel' (look it up)

author: TimFox
author_rank: Super Contributor
timestamp: August 06, 2021, 10:18:07 pm
content: I don’t know of any decent analog CROs still in production, but many of us buy used equipment for home use. Lots of pros and cons have been discussed on this site.

author: tautech
author_rank: Super Contributor
timestamp: August 06, 2021, 10:25:32 pm
content: Quote from: free_electron on August 06, 2021, 10:14:09 pmhttp://www.pintek.com.tw/product_classify/landersound-tail/index.php?Product_Site_Classify_SN=16856&Company_SN=6002

author: bdunham7
author_rank: Super Contributor
timestamp: August 06, 2021, 10:54:30 pm
content: Quote from: free_electron on August 06, 2021, 10:14:09 pmBK has discontinued their 100 and 60MHz versions, but they do have one refurbished 2160C left--60MHz, component tester, 1 year warranty. Last one!https://www.bkprecision.com/products/oscilloscopes/2160C-60-mhz-analog-oscilloscope-with-probes.htmlb/t/w, when was the last dual beam model manufactured???

author: james_s
author_rank: Super Contributor
timestamp: August 09, 2021, 05:33:20 am
content: As far as I know, there is no CRT production or rebuilding taking place anywhere in the world at this point, if they are still being built anywhere I'd like to know. It's possible the companies still selling new analog scopes are just selling old stock, I can't imagine they move many units at this point. I doubt it's going to be any cheaper to build an analog scope than a DSO these days.

author: AaronLee
author_rank: Regular Contributor
timestamp: August 09, 2021, 06:21:49 am
content: Quote from: free_electron on August 06, 2021, 10:14:09 pmThis place lists new Hameg HM-1005 scopes, but a bit pricey. 1,210,000 KRW comes to 1058.24 USD.https://www.kdk.kr/goods/goods_view.php?goodsNo=1000002865

author: tautech
author_rank: Super Contributor
timestamp: August 09, 2021, 08:39:04 am
content: Quote from: james_s on August 09, 2021, 05:33:20 amMaybe you didn't click on the link I posted above ?

author: james_s
author_rank: Super Contributor
timestamp: August 09, 2021, 07:08:28 pm
content: Quote from: tautech on August 09, 2021, 08:39:04 amThat link doesn't answer my question. Is anyone building CRTs still or are they just selling old stock? I don't see any information about price or availability, for all I know the web page could have been sitting there since 2005.

author: bdunham7
author_rank: Super Contributor
timestamp: August 09, 2021, 07:31:46 pm
content: https://www.thomaselectronics.com/faq/

author: james_s
author_rank: Super Contributor
timestamp: August 09, 2021, 07:35:55 pm
content: Fascinating, I had not heard of them. Looks like they mostly do avionics stuff, so $$$. I remember seeing an article somewhere a couple years ago that mentioned keeping CRT based avionics going was an increasingly difficult problem, and with an aircraft you can't just slap in a LCD conversion and call it good.

author: bdunham7
author_rank: Super Contributor
timestamp: August 09, 2021, 08:05:12 pm
content: Quote from: james_s on August 09, 2021, 07:35:55 pmThey even refurbish CRTs, so they appear to have a full glass lab. I'll bet that's not cheap either.If you look them up on Google Maps, you see they have two buildings and a fair number of employee cars in the parking lots, so not a micro-company. Older buildings, but they can afford to maintain the parking lot, so not likely in imminent danger of bankruptcy.208 Davis Pkwy, Clyde, NY 14433

author: richmit
author_rank: Contributor
timestamp: August 09, 2021, 09:08:53 pm
content: When I bought my first scope, I went digital. I have to say that my digital scopes have been faithful companions helping me through many projects over the past 20 years. A couple years ago I started playing around with analog computing and chaotic differential equations. XY mode suddenly becamemuchmore important to me.XY mode has never been great on digital, but it really feels like modern scope manufacturers are putting even less love into XY-mode than in the past. For example the XY mode on my Siglent SDS2504X+, and excellent device BTW, feels like an afterthought -- it's worse than on my 20 year old TDS3052B!So I bought my very first analog scope about a year ago -- a Tektronix 2205 for about $50 US from EBay. This 20MHz scope is about as low end as it gets, but I have to say it blows away every digital scope I have ever used for XY mode. Last month my wife got me a NIB Tektronix 2235 for my birthday.So, yea... After 20 years of using digital scopes exclusively, I have acquired two analog scopes in less than a year.Last week I needed to sweep a filter, and without really thinking about it I reached over and turned on the analog 2235...Don't get me wrong. I love my digital scopes -- especially the SDS2504X+. Still, I find myself occasionally cruising analog oscilloscope section of EBay. Something about the CRT and the way they work just makes them very satisfying to use...

author: Trader
author_rank: Frequent Contributor
timestamp: August 10, 2021, 05:00:57 am
content: Quote from: richmit on August 09, 2021, 09:08:53 pmMany people say the analog scope have more natural waveforms and adjustments, and I think the same.If you don't need to capture a single event, the analog scope is a great and useful instrument.

author: vk6zgo
author_rank: Super Contributor
timestamp: August 10, 2021, 05:57:33 am
content: Quote from: free_electron on August 06, 2021, 10:14:09 pm"Tin Drum"? ----Like the "Minion" here? (although it's only 10MHz)

author: vk6zgo
author_rank: Super Contributor
timestamp: August 10, 2021, 06:33:39 am
content: Quote from: james_s on August 09, 2021, 05:33:20 amDunno, but the little 10MHz analog job I have (see my previous posting) would be "dirt cheap" to build.They were still advertised on line a few years ago!Really "El Cheapo" DSOs have all the problems that plagued very early ones from the majors, in particular, horrific aliasing when looking at complex signals at long time/div settings.Analog video at field rate was the "torture test" for the old ones.A crappy little "10MHz" analog will still faithfully display a signal with frequency components to its specified bandwidth on very long time/div settings.I bought the horrible little thing to help me fix my BWD 'scope ages ago, but it ended up doing most of the jobs I needed it for nearly as well, (even at work), until I got the Tek 7613.Now, the Tek has croaked, & I have to go back to relying on the "Minion" to get me out of trouble.As I am now retired, I can put things "on the back burner", which is unfortunately where the 7613 is.The "Minion" is definitely "cheap & nasty"----things like knobs falling off, & BNC connectors coming unscrewed, & on one occasion, the HT supply failing.All these things are easily fixable---- the failed supply wasn't fussy about power transistors.I found one in the "junk box", fitted it,and:-"Aieeee! It lives!"

author: rsjsouza
author_rank: Super Contributor
timestamp: August 10, 2021, 05:37:26 pm
content: Quote from: vk6zgo on August 10, 2021, 06:33:39 amOver the years I reluctantly kept my original Kenwood CS4025 bought new more than twenty years ago - every time I think of getting rid of it, it becomes critical to look at something when my DS4014 is somehow not available.

author: tautech
author_rank: Super Contributor
timestamp: August 12, 2021, 05:40:45 am
content: Quote from: james_s on August 09, 2021, 07:08:28 pmYou doubt my sources ?20 MHz $315 to 100 MHz $ 525 ex factory Taiwan.Yeah, why would you buy a new one ?

author: james_s
author_rank: Super Contributor
timestamp: August 12, 2021, 05:57:48 am
content: Quote from: tautech on August 12, 2021, 05:40:45 amWho's doubting anything? I just can't tell from the link whether they're still being manufactured or not, I mean who is buying them? I figured any still for sale would be old stock, they can't possibly move very many at this point, especially at those prices.

author: rauldm
author_rank: Regular Contributor
timestamp: July 10, 2022, 06:02:15 pm
content: think an advantage analog oscilloscope is for waveform with sweep I remember is nice to view it, I had a Tektronix 2247a, with 1 ms sweep rate the visualization is nice, if compared sweep waveform even with MDO3054 is better in analog oscilloscope, AM signals looks similar even in my low cost siglent with SPO tecnology. Finally I sold that scope for is big an heavy, measurements and cursors have poor accuracy.I have Tek MDO3054, TDS3012B agilent dsox2002a, siglent 1104x-e, GW GDS2202E all with DPO SPO or every name that's means Phosphor emulation, Also I have Scopemeter Fluke, this scope is not has phosphor emulation therefore waveform visualizaion is bad compared with analog scope.Maybe low cost DSO and analog was a good combination when phosphor emulation was very expensive, but visualization performance for example in siglent 1104x-e is so good like TDS3012B, I think analog scope can works for comparing repetitives waveforms with DSO, non repetitive waveforms in analog oscilloscope is imposible, display is little compared with moderns DSO, is extremely limited on functions and triggers, I want an Iwatsu 7811 or lecroy 302 only for this propuse, but big size is limitation because takes same space a power supply and bench multimeter or waveform generator, are very noising, probe attenuation is other problem, only 10 or 100x with readout pin, arbitrary attenuation is imposible, active probing? imposible, some high frequency signals must be analized with active probe, pasive probe change drastically its impedance with high frequency even inside bandwidth.Single shot function is impresindible for diagnostic or other specialized function, I only work in repair industrial and agriculture electronics, capturing for my is essencial, but all people has different needs, I think analog scope can be only optional, if space is not a problem, if you can buy a scope for a good price in work conditions can be good buy. up to 200 usd maybe 250 usd good price, near to 400 USD can you get a SDS1104X-E.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: July 11, 2022, 08:32:38 am
content: First, is it even possible to buy a decentNewanalog oscilloscope anymore?I had a look at the pintek site mentioned earlier, but they don't list prices, which is an instant dismissal for me.When you look at "regular" sites (batronix, saelig, reichelt, welectron, digikey) then you can't even buy a decent analog scope anymore.Digikey lists the Ownon AS201, which turns out to be a 20MHz single channel digital scope trying to mimick an analog schope (Why would anyone buy that for USD250?)I did find:https://www.conrad.nl/nl/p/voltcraft-analoge-oscilloscoop-ao-610-10-mhz-1-kanaals-122413.htmlBut that toy has only one channel, 10MHz and a screen so small it's just silly and with a price tag of EUR255 it's more expensive then an entry level digital scope, such as this (rebranded as) Peaktech scope for EUR220.https://www.reichelt.nl/nl/nl/digital-speicher-oszilloskop-20-mhz-2-kanaele-peaktech-1402-p321524.html?&trstct=pol_6&nbc=1Those bulky things have really gone the way of the dodo.Quote from: Trader on July 29, 2021, 04:09:45 pmComparing some 20+ year old analog scope to a new digital tektronix / keysight / R&S etc, is a quite silly comparison. Some people may be addicted to analog scopes, but the biggest market will be people with a tight budget, and there is a plethora of decent digital scopes starting around EUR 350, and those are a much better choice for beginners. DSO's just have too many advantages over those analog beasts to be taken seriously.There probably is still a niche for people who really need 500MHz, but can't afford a DSO with that bandwidth, although you can get a 300MHz DSO below EUR 700.https://www.reichelt.nl/nl/nl/digitale-oscilloscoop-met-geheugen-300-mhz-2-kanalen-rigol-ds2302a-p327496.html?&trstct=pol_0&nbc=1

author: Kleinstein
author_rank: Super Contributor
timestamp: July 11, 2022, 09:50:28 am
content: There are essentially not new analog scopes for a reason. Even the entry level ($300-$500) DSOs are better than most analog scope excepts a few old high end models that can offer a little better BW than the cheap DSOs.The XY mode is a bit weak with some DSO models, but it is rarely used anyway.A used analog scope may still be available relatively cheap, if one can live with the limitations - with some experiance one can work around some, but not all.Especially very slow signals and single/rare events is where an analog scope fails.In the sub $100 range a used analog scope may be still atrractive over a cheap DSO with a tiny screen and often quite some limitations.

author: vk6zgo
author_rank: Super Contributor
timestamp: July 11, 2022, 11:20:50 am
content: Quote from: Kleinstein on July 11, 2022, 09:50:28 amIn the early days of DSOs, relatively slow, but complex signals, like field rate analog video were their "Achiile's heel".Long time/div settings reduced the sample rate to a few tens to hundreds of kHz, making them totally unuseable for a signal with 5MHz components.Even when I first joined this forum, that was a limitation of some really cheap DSOs.The really cheap "toy" things like DSO 138s & the like still offered, all suffer from that problem, whereas the litte analog referred to byDoctorandus_Pstill offers an honest 10MHz, even if it does look like something designed to be used by "Cabbage Patch Kids!"It is, however, ridiculously priced!If the thing doesn't actually lie to you, like the early, & the later "toy" DSOs, you can do useful work with the most basic of instruments.

author: tggzzz
author_rank: Super Contributor
timestamp: July 11, 2022, 11:51:24 am
content: Quote from: Kleinstein on July 11, 2022, 09:50:28 amExcept where you have an anaogue storage scope, preferably dualbeam. But that is scraping the barrel; analogue storage scopes were a pain. (Having said that, I surprised at how much I don't dislike my Telquipment DM63!)Single shot events always were the killer use case for digitising scopes. But for a long time the number of samples captured in a digitising scope was a real limitation, especially coupled with the lack of "peak display".Nowadays a drawback for a beginner is the complexity of all the sampling and display modes which can drastically affect what you see/discover in a digitising scope. Doubly so when the config is hidden 4 levels down in amazemenu hierarchy.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: July 11, 2022, 12:00:43 pm
content: I browsed a bit around on Aliexpress, and some new analog scopes are still being offered. The 20MHz scopes cost about the same as their DSO counterparts and there even are some 100MHz CRO's, but they cost over EUR 700.What finally does them in is the shipping of the big and heavy things. They're probably also a lot more vulnerable during shipping.I've bought quite a lot of stuff from Ali, but I won't buy a scope there. Buying locally is about the same price (Even inclusive the 20% EU tax) and buying local gives you normal warranties and such.

author: rstofer
author_rank: Super Contributor
timestamp: July 12, 2022, 04:55:03 pm
content: Quote from: tggzzz on July 11, 2022, 11:51:24 amJust like any analog scope, the important controls are V/div and t/div. I suppose a few channel selections are important like 1x vs 10x but that's pretty easy to find. Trigger controls are quite similar (which channel, trigger voltage). One shot is different because analog scopes can't even do that (mostly). But it's pretty simple!All of the stuff buried deep in menus is related to advanced functions that analog scopes can't even do. These settings can be easily ignored until the feature becomes necessary. Maybe that comes up some day, maybe it doesn't.I don't find the menu system of the Rigol DS1054Z to be all that complex.Of course, the user could try the old fashioned approach and RTFM. It's all there...Incidentally, I have had a Tek 485 for nearly 20 years and I still don't know what all of the controls are for. I do know where to find V/div, t/div and trigger threshold. The other features just haven't been that important for me. Other opinions will vary wildly.ETA: Don't overlook the 'Auto' button on the DSOs. It will get a display on the screen. Maybe some settings need to be tweaked, maybe not. The purists will probably laugh at anyone professing to use the button. Go ahead, laugh, I use it all the time because I don't always remember what I did to the setup when last used a few months ago.

author: tggzzz
author_rank: Super Contributor
timestamp: July 12, 2022, 07:40:38 pm
content: Quote from: rstofer on July 12, 2022, 04:55:03 pmNot necessarily.With an digitising scope I rapidly find the need to set it to "show me all samples not just the average, so I can see what is really there". I conjecture that many beginners haven't displayed the peaks, and so miss that the reason their circuit "isn't working" is that it is oscillating much faster than they thought possible.Ditto finding how to set "show samples, don't draw straight lines between samples". I've seen the latter unnecessarily give very confusing and pessimistic display.Basically I hate tools that attempt to "know what I need", because they always get it wrong one way or another. One bete noire is the fuel guage on my 1993 Toyota; there's an effin' computer between the sensor and the display. I park on a slope, and that means that it "reads low". I can deal with that. Unfortunately it doesn't read correctly when driving along horizontal roads - unless it has been parked on the flat for several hours. In the worst case it thoroughly confused itself, with the result that the car refulled itself while travelling at 70mph on a 5km bridge across the River Severn.QuoteYou can get used to any tool, even WindowsQuoteAn experienced usercando that; whether theydodo that is a separate issueBut not beginners. They are rapidly overwhelmed by all the options, and don't have an internal conceptual framework for understandingwhythey are there nor when they would use them. The same is true for analogue scopes, but they are simpler and everything is "in their face".QuoteI don't laugh at auto; it is a more sophisticated variant of the "beam finder" button. I do dislike it leading to lack ofthinkingabout whatoughtto be visible in the circuit.

author: David Hess
author_rank: Super Contributor
timestamp: July 12, 2022, 08:16:10 pm
content: Quote from: Kleinstein on July 11, 2022, 09:50:28 amPerformance has nothing to do with why DSOs replaced analog oscilloscopes.Analog oscilloscopes depended on established technologies like electrostatic deflection CRTs and wide bandwidth high voltage vertical CRT amplifiers which do *not* benefit from increasing semiconductor integration. These established technologies were as cheap as they were going to get. DSOs were primarily limited by semiconductor integration for price and performance, which means they followed the geometric increase of integration just like computers did, resulting in low prices.Early DSOs had a large cost premium over analog oscilloscopes, but some people were willing to pay it in selected applications where digital storage and processing was worth the cost. Later DSOs were so cheap, because of increased semiconductor integration, (1) that they completely replaced analog oscilloscopes, whether they had better performance or not.(1) Displays become cheaper also, and still are.

author: David Hess
author_rank: Super Contributor
timestamp: July 12, 2022, 08:41:53 pm
content: Quote from: tggzzz on July 12, 2022, 07:40:38 pmI think a display mode which duplicates the fidelity of an analog display but also highlights peaks is possible, but manufacturers consider only checklists of increasingly less important features, including maximum possible record length for a given investment in RAM, even if it lowers performance. Customers purchase based on record length, and not human factors engineering.

author: rstofer
author_rank: Super Contributor
timestamp: July 12, 2022, 08:50:36 pm
content: Quote from: tggzzz on July 12, 2022, 07:40:38 pmHere is an EPIC thread where a new user buys a scope and then decides to test EVERY feature, one by one. The link starts less than half way through the pages and there are a lot of pages but we cover a LOT of ground. I had never used the scope to show the integral of a waveform. What a trip!https://www.eevblog.com/forum/beginners/what-an-oscilloscope-recommended-for-a-woman-passionate-about-electronics/175/Charlotte buys a Siglent SDS1202X-E at post 150 (page 7) and it goes on for another 30 pages.It IS possible to work through many of the examples in the User Manual without even having a signal source. The compensation signal can be used for many demonstrations including the FFT feature.

author: tggzzz
author_rank: Super Contributor
timestamp: July 12, 2022, 09:13:57 pm
content: Quote from: rstofer on July 12, 2022, 08:50:36 pmCharlotte was clearly interesting and exceptional. I encouraged her early in the thread, then others took over:)I don't think she affects the basic points..

author: tggzzz
author_rank: Super Contributor
timestamp: July 12, 2022, 09:19:22 pm
content: Quote from: David Hess on July 12, 2022, 08:41:53 pmI wouldn't want to claim that analogue scopes have greater fidelity than digitising scopes. Different tools have differing advantages and disadvantages. Digitising scopes, arguably, offer more than analogue scopes, but that comes at t cost of simplicity and basic usability.That basic usability is often ignored by some people.

author: tautech
author_rank: Super Contributor
timestamp: July 12, 2022, 09:36:23 pm
content: Quote from: tggzzz on July 12, 2022, 09:19:22 pmThey do and the differences for a similar type of instrument can be vast.QuoteThis I take issue with as it's very wrong.Analogue or digital, they all have a V/div, s/div control, brightness/intensity, graticule, and trigger level and slope all the basic things you need to display the simple repetitive waveform.Yeah a DSO looks different so will the next car you buy. Scopes are tools that come in many different colors and sizes but they all do the same basic thing, display electrical waveforms.QuoteOnly those that haven't engaged their grey matter and let what they see in front of them cloud their judgement to what the tool can do.

author: tggzzz
author_rank: Super Contributor
timestamp: July 12, 2022, 09:41:29 pm
content: Quote from: tautech on July 12, 2022, 09:36:23 pmYou deliberately and explicitly ignore the extra complexity, and choose to concentrate on some simp!e examples that suit your point and purposes.Not impressive.

author: rstofer
author_rank: Super Contributor
timestamp: July 12, 2022, 10:31:40 pm
content: Quote from: tggzzz on July 12, 2022, 07:40:38 pmIn terms of getting dots versus vectors on the screen, it's a pretty easy button sequence (on the Rigol DS1054Z)QuoteNo, I didn't know how to do it, never cared. I just popped open the User Manual and searched for 'dots'. The third hit was right on the money. Didn't take even a minute.Now, whether any dot is actually at the 'peak' is a different story. But that's the problem with any sampling algorithm. 'Equivalent Time Sampling' comes to mind. If you have a lot of dots relative to the period of the signal, your chances of hitting the 'peak' are much improved.

author: tggzzz
author_rank: Super Contributor
timestamp: July 12, 2022, 11:24:13 pm
content: Quote from: rstofer on July 12, 2022, 10:31:40 pmI've no reason to doubt that, but an equally valid counterexample is one I found on an otherwise decent and well respected HP series scope. There it was a couple of menus deep, and unforgivably reverted to the default when just about anything change.When coupled with some other quite reasonable settings, the display wastotallyunrepresentative of the real world.Complexity is something to be avoided as far as possible but no further.QuoteThere is no reason to believe an indicated peak is the actual peak, but that isn't too important. Analogue scopes have snalogous problems.The point is that without something like the (appallingly named) peak display, a digitising scope activelyconcealshe complexity of reality+instrument.

author: tautech
author_rank: Super Contributor
timestamp: July 13, 2022, 01:01:59 am
content: DSO Peak detect and Persistence will display waveforms totally invisible to a CRO.Go get a modern one and learn how powerful they really are.

author: David Hess
author_rank: Super Contributor
timestamp: July 13, 2022, 03:45:05 am
content: Quote from: tggzzz on July 12, 2022, 09:19:22 pmI would claim it. The proof is that the user can make a tangential measurement on an analog oscilloscope with just their eye to find a real RMS value in amplitude or time. The display on an analog oscilloscope is a direct representation of a real otherwise difficult to perceive property.One of the things I considered in my paper DSO design was displaying that RMS value as part of the display record of the histogram, instead of requiring the user to literally eyeball it. If peaks are going to be highlighted on the display, then why not? (1) Right now the only way a DSO can show part of it is with a gated RMS measurement. (3) On the other hand it may be of questionable utility; how many users ever have a need to make a gated RMS measurement? On the gripping hand, it does represent something real which is otherwise lost.(1) Tektronix did something like this on one of their first DSOs, the 2232. I think it works by applying a noise gate to the signal, but since it could not have been done during decimation, I am not sure how they got it to work as well as it did. The result was removing the oscilloscope noise, while highlighting peaks. Luckily it can be disabled, although it works surprisingly well. (2) The photo below shows the impossible result. I did not notice it at the time or I would have made recording with and without it enabled. Ignore the vertical striping; that is a limitation of the 2232 display list processor. I am using this as an example of display processing which either improves usability, or destroys, it depending on your point of view.(2) I never saw this feature in another DSOs, by Tektronix or anybody else, so I wonder if Tektronix concluded later that it was a bad idea because it arguably makes the display less representative of what is really going on.(3) High end DSOs can display a "slice" of the display histogram to reveal the distribution, but I do not remember seeing the calculation.QuoteI do not think that tradeoff must be made, but some differences are for cost or space reasons, like having a single set of vertical controls for multiple channels. Soft menu touch controls are cheaper than hard controls.QuoteI agree for the reasons I gave.