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We called it what it was----a "amplitude/frequency response test".
FRA is what it's more commonly called today and yes some modern and cheap DSO's do it surprisingly well although for some models an external stimulus is required whereas others have it inbuilt.
Back the day, VNAs were "rare as hen's teeth" so we didn't normally have the occasion to do "phase/frequency" testing.
Do the common modern DSOs perform both of these types of test?
Have a look at rf-loop's investigations of the limits of what the little 4ch X-E's can do:
https://www.eevblog.com/forum/testgear/siglent-sds1x04x-e-bodeplot-ii-(sfra)-features-and-testing-(coming)/ -
I can also do the timing and adjust the points, synchronize the carbs and prep the plugs on my '74 RD350. Many here would be at a total loss and never be able to enjoy the feel of riding an untamed, raw twin cylinder 2-stoke bike of epic reputation. I pity those that cannot appreciate where they, or their world, came from.
Nice bike and when they were all the rage known as real death traps for the unwary due to their raw power.
IIRC they evolved from the RD250 one or maybe both had LC versions too with even more power.
They 250 took the crown from the Suzuki GT250 X7, an air cooled twin and the first mass produced bike to do the ton. (100mph)
https://en.wikipedia.org/wiki/Suzuki_GT250
I had one of the last of these in black with mags and it certainly would do the ton however you always kept your eyes open for an LC Yammy and if one appeared you just nodded and let him go.
Amazed yours has points as mine being near the end of a long production run had upgraded to CDI.
Talking about general purpose scopes for engine tuning a buddy with a 13B twin rotor doorslammer drag car had issues at half track where they we losing power and traced it with a DSO as low output into one coil that at full power and boost was insufficient to keep the fires going.
Even today a DSO gets pulled out to tune max revs on any of my chainsaws that all rev out at some 11k rpm which equates to a very leisurely 183 Hz. -
An especially useful feature of DSOs is the ability to display the waveform in a single sweep before the triggering event.
Agreed, that's something which the unlamented analogue storage scopes couldn't do.
It is less compelling with repetitive waveforms, of course.
Analog 'scopes with delay lines can display the waveform in a recurrent waveform before the trigger event, although it is seldom essential.
Yes, but not by much and only a fixed amount
I'll disagree about it being rarely essential. I frequently have to look at the signal integrity and phase relationships of relatively slow digital waveforms. Being able to see the leading edge of a waveform without having to have a very long delay is beneficial. Example: looking at the leading edge of a 10kHz signal with 10ns risetime. -
We're all living in an environment. Despite the obviousness, the environmental factor is not mentioned it the thread so far. I've two old portable scopes, and I'm also not going to get rid of them any time soon. The scope can operate in wide temperature range, up to -30 degree C. That's nothing exceptional for a service class equipment. It's designed for use in a place like a cold garage or a hangar. That capability is required for a task like to investigate what's wrong with welding machine, which is too big to move indoor. It's a waste of time to figure out the price for a DSO with that capability.
And by the way my shiny new Rigol DSO failed after the first month of use at the lab bench. Sure, it's just Rigol, the other brands of similar breed can never fail, but anyway
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Nice bike and when they were all the rage known as real death traps for the unwary due to their raw power.
The 250 and the 350 both evolved from older version. The RD was first introduced in 1973. The RD350 followed the R5 and the RD250 followed the DS7. The big addition to the RD line was reed valves in teh induction. The 1973 RD350 also got a disk brake over the 1992 R5. The RD250 did not get the disk until 1974.
IIRC they evolved from the RD250 one or maybe both had LC versions too with even more power.
The Suzuki GT250 was a decent bike and was Suzuki's 1971 follow-up to it's legendary X6 Hustler. The X6 had a 6-speed transmission which was really cool at the time. The GT250 inherited this an got the front disk 3 years before the Yamaha RD250. By 1974 Gt250 was a good match for the RD250 and could easily hang with it although the RD was a bit nicer in the twisites. However, the Suzuki GT380 was a bit of an underpowered pig compared to the RD350 and was not even decent competition, performance wise, for it's smaller sibling (GT250).
World wide there were LC versions of both the 250 and 350 but in NA 1974 was the last year for the RD250.
Yeah, my '74 RD has points. Even my 1976 RD400 had points. -
My Brother had a Yamaha 350
I had a Harley Sprint 350, actually an Italian MC also 350. 4 stroker. Aermacchi.
He could barely beat me from a stop.
But he outweighed me by 40 #
The way to tune an Aermacchi was to adjust the valves and points to "racing specs" and to tune the thing so it would barely run at idle, it would sound terrible at idle but accelerate very well. -
It seems Dave J. likes to have a CRO around too.
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It seems Dave J. likes to have a CRO around too.
And you dig out an 11 year old video.
You for one know times have changed and the 3 scopes Dave went on to rabbit about having 500uV/div ranges, well most of Siglent's DSO's have that too. -
It seems Dave J. likes to have a CRO around too.
I would think most engineers have one kicking around somewhere. Most don't actually use it often but why get rid of it? Using a CRO is a bit like driving a classic car, it's just fun, and it's still as useful as it ever was. -
Yes, but the 500uV is why he chose that scope, not why he got himself an analog scope. He gave several reasons to own an analog scope and they have not changed.It seems Dave J. likes to have a CRO around too.
And you dig out an 11 year old video.
You for one know times have changed and the 3 scopes Dave went on to rabbit about having 500uV/div ranges, well most of Siglent's DSO's have that too.
I'd never give up my DSOs and if I was forced to have only one of my scopes it would be my SDS2504XP, but my Tek 465 would not be the fist to go. I can see only upside to having both.
But I will say I honestly think that if you only had $175 to buy a standalone scope with, you'd get a much better scope going analog. Just ask all our unfortunate friends here that own FNIRSI and Hantek DSO2x1x scope shaped bricks. -
Still, today Dave recommends a DSO. This question has been put to him many times over the years and for the last few a DSO is his recommendation and sure I can hear you all say not everyone has that budget to invest.
Yet if funds were really tight many would consider the investment in old and possibly unreliable technology unwise and force themselves to wait and save for something that will serve them better.
Everyone has their own way of moving forward based on how important an electronics hobby or profession is to them.
Scopes are like eyes into a new world and with the modern feature sets, total investment is dramatically reduced.
Never have we had such good choices at such good pricing. -
Still, today Dave recommends a DSO. This question has been put to him many times over the years and for the last few a DSO is his recommendation and sure I can hear you all say not everyone has that budget to invest.
Yet if funds were really tight many would consider the investment in old and possibly unreliable technology unwise and force themselves to wait and save for something that will serve them better.
Everyone has their own way of moving forward based on how important an electronics hobby or profession is to them.
Scopes are like eyes into a new world and with the modern feature sets, total investment is dramatically reduced.
Never have we had such good choices at such good pricing.
Well Tautech I think I'll up my selection and go for the SDS2202X-E that's my present to myself this year.
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Yet if funds were really tight many would consider the investment in old and possibly unreliable technology unwise and force themselves to wait and save for something that will serve them better.
Certainly if the buyer did not have the ability to judge the condition of the scope nor the ability to fix it up, they should not get a used scope of any kind.
Yeah, things are getting wildly better all the time. My old Uni-T UTD2102CEL was a kick ass scope at the time (the top of Uni-T's 2000 series scopes) but now you can get it's capabilities in a scope that costs under $300. If you look at the SDS2000XP scopes you'd have to pay the price of a small car to get that capability 12 years ago. 12 years from now we'll probably have 1GHz scopes for $399 with features we can only imagine. -
IMHO the better feature set is in the 4ch X-E however they are just a 200 MHz design whereas SDS2000X-E are a 350 MHz design so if you only need the BW then 2kX-E is the better choice.Still, today Dave recommends a DSO. This question has been put to him many times over the years and for the last few a DSO is his recommendation and sure I can hear you all say not everyone has that budget to invest.
Yet if funds were really tight many would consider the investment in old and possibly unreliable technology unwise and force themselves to wait and save for something that will serve them better.
Everyone has their own way of moving forward based on how important an electronics hobby or profession is to them.
Scopes are like eyes into a new world and with the modern feature sets, total investment is dramatically reduced.
Never have we had such good choices at such good pricing.
Well Tautech I think I'll up my selection and go for the SDS2202X-E that's my present to myself this year.
Little things it offers the 1kX-E doesn't are 50 Ohm inputs but it has been left behind with the ongoing rollout of features into the 4ch X-E's.
I've pushed the 350 MHz model past 600 MHz and it still triggered and displayed the frequency.
SDS2202X-E is pretty cheap HP at just $620 considering you can open it up to 350 MHz and it will keep you busy discovering all it can do. Hope it likes you.
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I've pushed the 350 MHz model past 600 MHz and it still triggered and displayed the frequency.
SDS2202X-E is pretty cheap HP at just $620 considering you can open it up to 350 MHz and it will keep you busy discovering all it can do. Hope it likes you.
I've pushed my 350MHz Tek 485 past 1.1GHz, and the triggering was rock stable and the waveform was perfectly displayed albeit reduced in amplitude
I only paid £50, but a more usual price would be £200. You couldn't make a business out of selling them, thoigh. -
Screenshots required as proof please.I've pushed the 350 MHz model past 600 MHz and it still triggered and displayed the frequency.
SDS2202X-E is pretty cheap HP at just $620 considering you can open it up to 350 MHz and it will keep you busy discovering all it can do. Hope it likes you.
I've pushed my 350MHz Tek 485 past 1.1GHz, and the triggering was rock stable and the waveform was perfectly displayed albeit reduced in amplitude
Thanks, needed this push to find the old posts.....with screenshots:
https://www.eevblog.com/forum/testgear/dso-bandwidth-test-sds1104x-e-dsox1102g-to1104-gds1054b/msg2391324/#msg2391324 -
Screenshots required as proof please.I've pushed the 350 MHz model past 600 MHz and it still triggered and displayed the frequency.
SDS2202X-E is pretty cheap HP at just $620 considering you can open it up to 350 MHz and it will keep you busy discovering all it can do. Hope it likes you.
I've pushed my 350MHz Tek 485 past 1.1GHz, and the triggering was rock stable and the waveform was perfectly displayed albeit reduced in amplitude
I'm away for Christmas, so none are available ATM.
The triggering would have worked at higher frequencies thanks to the tunnel diodes in that part of the circuit. The only reason I couldn't push it further was because the amplitude was reduced to 0.2 div, the min specified for triggering. -
Do true analog scopes still get produced? is there a market for them or specialized applications for which a digital scops is not suitable? I suppose too that a true analog scope couldn't really use a digital display unless the resolution of the screen was huge and that in turn implies there'd need to be some kind of A/D conversion involved, so it wouldn't be true analog scope...
Analog scopes are better for somethings because they can show the difference between regular noise and noise caused by the circuit sometimes when the noise is very small. The noise can indicate a problem with the circuit and when it is small it could be the scope so you cant tell if it is the scope or the circuit if using a digital scope sometimes. An analog scope has a very smooth output unless there is noise so the noise will show up differently, sometimes has just one tiny bump. If the digital scope naturally has several tiny bumps you cant tell if it is the circuit or the scope.
This can be a problem troubleshooting some power converters such as sine synthesized converters that output a nearly clean sine wave. When i did some troubleshooting long time ago the rule was no digital scopes even though we could have gotten some more information from using one such as FFT.
These days digital scopes are better than back then, but there will always be that scope noise vs circuit noise issue which may or may not be an issue depending on what kind of circuit you are dealing with.
I prefer a digital scope these days because they are so much smaller and once you get to know them you can do a lot with them. There may be times when you run into a problem though.
For a very extreme example, try illustrating the Lorentz Force Law:
F = qE + qv × B
using a digital scope. It's impossible because there is no electron beam (ha ha) to be influenced by an electrostatic or magnetic field.
With an analog scope it's simple, fast, and easy. It's also very direct because there are no intermediate sensors required.
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.. they always lack the basic functionality of a true spectrum analyzer, like a noise marker and correction for RBW. These things would be trivial to add, but for whatever reason DSO designers decline to do so.
Well if they did, how would they convince you to buy their spectrum analyzer?
Perhaps, but the capabilities and use cases are not the same. A DSO with these features is more comparable to a low frequency network analyzer.Any sweep function generator with any half-way decent scope with a second channel or external trigger input can do it:
I can tell you that trick is nothing like the real thing.
The usefulness depends a lot on the sweep generator and oscilloscope. My sweep generator can produce logarithmic sweeps making the display easier to read, and if for instance a Tektronix 2247A or 2236 analog oscilloscope is used, the oscilloscope can place a marker on the screen showing the frequency and separately amplitude at that point. I have had less success using DSOs like this because they do not make an integrated gated frequency measurement, so their frequency accuracy is more limited.
I think the Tektronix 2465 series with the timer/counter option can work like this also.You for one know times have changed and the 3 scopes Dave went on to rabbit about having 500uV/div ranges, well most of Siglent's DSO's have that too.
The only reason that the 2225 has a 500 microvolt/division range is that its lower bandwidth design is lower noise which allows it, and it is lower noise than the Siglent DSOs without severe bandwidth limiting or averaging. That is after taking into account how peak-to-peak noise is displayed on an analog oscilloscope. Dave did not quantitatively measure the noise of the 2225 when he made that video.
I would still prefer the Signlent DSO to the 2225 baring exceptional circumstances. I use old oscilloscopes because they are the most cost effective for me, but that is not the case for most people.
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It seems Dave J. likes to have a CRO around too.
Oi. I have enough messages from people asking me to review their products in videos because they've confused me with this site's owner (
) without you adding to the problem by referring to him using my forum name (see sig).
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The basic problem with the Scope-Sweep Generator method for Bode Plots, and we've used them in the past, is the lack of Vertical dB scales (linear Vertical screen resolution limited to 30~40dB range, and no dynamic V axis scaling), and the lack of any direct Phase plots. The modern DSOs under discussion do a respectable job here, some completely self-contained (built-in AWG), have dB Vertical scales (some with dynamic scaling over 100dB), direct Phase plots, and allow direct digital document recording/printing of the results.
Recall long ago doing the analog Scope-Sweep Generator Bode routines, and having to capture photos of the scope screen, and having very limited Linear vertical scale factors, then having to generate the phase plots by measuring the time delay shift between scope channels, calculating the phase shift, tabulating and hand creating a Phase plot on the Xerox scanned magnified version of the Polaroid image of the scope screen.
We'll take the DSO Bode capability over this Scope-Sweep Generator routine any day, thank you!!
Sure if one has direct access to a Network Analyzer (we did, but these were often under use by others) that's better than the Scope-Sweep Generator routine, or even the modern DSO Bode capability. However, many don't have direct access to a NA, and they tend to be very expensive, even on used market, so a DSO at hand (if available) can serve a very useful purpose here.
Been around a long long time and done just about every imaginable measurement possible, often even having to design our own test equipment because nothing was available from anyone that could do what was required measurement-wise. Must say these new DSOs are remarkable in the ability to do almost anything and everything a quality analog (Tek) scope could do, and also perform respectable measurements that other dedicated equipment was often acquired for. To add icing on the cake, the relative cost of these modern DSOs is modest, especially compared to their overall capability.
This is from an old diehard analog type, that spent 60+ years with Tek and HP equipment, and finally decided to get our own modern DSO a few years ago (long story) to play around with
Best & Happy Holidays
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I still use an analogue scope.
Bought it about 10 years ago for £45 on ebay.
Channel 2 was faulty when I bought it and still is but can be used if a voltage offset isnt a problem.
I find using software on microcontroller to output signals a distance apart I can get the analogue scope to trigger better.
Most of the stuff I design and build is sub 20MHz so it works fine.
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Something I don't miss at all with analogue scopes....all the mental arithmetic just to use the scope vs a DSO that when set correctly excludes all that BS and instead lets you focus on the DUT measurement instead.
Pinched from another thread as a fine example:
Apparently using a 100x probe.
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Something I don't miss at all with analogue scopes....all the mental arithmetic just to use the scope vs a DSO that when set correctly excludes all that BS and instead lets you focus on the DUT measurement instead.
Aw. Bless.
It is really kind of young people to make graybeards feel younger, by favourably comparing graybeards' deteriorating cognitive abilities with the non-deteriorated abilities of the youngsters.
Maybe that suggests a new sales pitch targeting a new demographic..
"Starting to have problems with mental arithmetic? Never mind; conceal it by buying a Siglol oscilloscope".