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Products => Test Equipment => Topic started by: bigfede on February 15, 2023, 08:14:29 am

Title: Help me choosing new Oscilloscope
Post by: bigfede on February 15, 2023, 08:14:29 am
Hello everybody,

I have no decided yet, but I'm looking around to see which is suitable for my application. I had in the past the DS1054Z unlocked. Recently I've sell it on eBay trying to upgrade my bench.
In general I do not use scope for "fast" signals (I have never measured signals faster than 10MHz) but just for power supplies ripples, data bus, and so on. Never used for any kind of HF application. So my question is, can you help me choosing ?
My budget: 1000-1500€ and I have seen the MSO5074 and the HDO1074. I know they are pretty different from each other, but thinking about the future I don't know which is the "best" choice. I know that MSO5000 have huge sample rate with respect to HDO1000.. but is it really important?

Thanks in advance for any suggestions.
Title: Re: Help me choosing new Oscilloscope
Post by: tggzzz on February 15, 2023, 09:37:56 am
In general I do not use scope for "fast" signals (I have never measured signals faster than 10MHz) but just for power supplies ripples, data bus, and so on. Never used for any kind of HF application.

"Data bus" implies a digital waveform implies you are measuring fast signals. Hint: the clock rate is irrelevant: all that matters is the transition time.

FFI, with a little theory and some demonstrations: https://entertaininghacks.wordpress.com/2018/05/08/digital-signal-integrity-and-bandwidth-signals-risetime-is-important-period-is-irrelevant/
Title: Re: Help me choosing new Oscilloscope
Post by: Fungus on February 15, 2023, 09:50:54 am
In general I do not use scope for "fast" signals (I have never measured signals faster than 10MHz) but just for power supplies ripples, data bus, and so on. Never used for any kind of HF application. So my question is, can you help me choosing ?
My budget: 1000-1500€ and I have seen the MSO5074 and the HDO1074. I know they are pretty different from each other, but thinking about the future I don't know which is the "best" choice.

We know even less about your future than you do.  :-//

HDO1074 is best for power supply ripple.

MSO5074 is best for data buses.

What sort of power supply ripple do you need to see? Are you worried by 50mV, by 5mV or by 0.5mV?
Title: Re: Help me choosing new Oscilloscope
Post by: bigfede on February 15, 2023, 09:58:36 am
In general I do not use scope for "fast" signals (I have never measured signals faster than 10MHz) but just for power supplies ripples, data bus, and so on. Never used for any kind of HF application.

"Data bus" implies a digital waveform implies you are measuring fast signals. Hint: the clock rate is irrelevant: all that matters is the transition time.

FFI, with a little theory and some demonstrations: https://entertaininghacks.wordpress.com/2018/05/08/digital-signal-integrity-and-bandwidth-signals-risetime-is-important-period-is-irrelevant/
That's pretty interesting article! Thanks a lot.
Title: Re: Help me choosing new Oscilloscope
Post by: bigfede on February 15, 2023, 10:01:55 am
In general I do not use scope for "fast" signals (I have never measured signals faster than 10MHz) but just for power supplies ripples, data bus, and so on. Never used for any kind of HF application. So my question is, can you help me choosing ?
My budget: 1000-1500€ and I have seen the MSO5074 and the HDO1074. I know they are pretty different from each other, but thinking about the future I don't know which is the "best" choice.

We know even less about your future than you do.  :-//

HDO1074 is best for power supply ripple.

MSO5074 is best for data buses.

What sort of power supply ripple do you need to see? Are you worried by 50mV, by 5mV or by 0.5mV?

Good point. The answer is that I don't know  |O
Basically I'm looking for a valid upgrade. Usually 5mV is sufficient on most of my application.
Title: Re: Help me choosing new Oscilloscope
Post by: Fungus on February 15, 2023, 03:43:17 pm
Even with its noisier front end the MSO5000 should show if ripple is >=5mV, no problem.
Title: Re: Help me choosing new Oscilloscope
Post by: bigfede on February 15, 2023, 04:14:12 pm
Ok, but any competitor? I mean I've always used Rigol or Lecroy, but is there any good competitor to this model?
Title: Re: Help me choosing new Oscilloscope
Post by: wasedadoc on February 15, 2023, 04:27:08 pm
Not clear why you sold the hacked Rigol DS1054Z as it seems to be perfectly adequate for the tasks you list.
Title: Re: Help me choosing new Oscilloscope
Post by: bigfede on February 15, 2023, 04:29:35 pm
I was able to sell it to a well good price!
Title: Re: Help me choosing new Oscilloscope
Post by: JeremyC on February 15, 2023, 04:43:03 pm
Ok, but any competitor? I mean I've always used Rigol or Lecroy, but is there any good competitor to this model?

You should check the Siglent SDS2104X Plus, it can be easily hacked to 500MHz and has very low noise front end.

In the EU you can get the SDS2104X+ for ~1199 Euro from “Batter Fly”, link below
https://www.batterfly.com/shop/en/siglent-sds2104x-plus (https://www.batterfly.com/shop/en/siglent-sds2104x-plus)

Check the SDS2104 and MSO5074 side by side review:

https://www.youtube.com/watch?v=93QUNt1z6Gw (https://www.youtube.com/watch?v=93QUNt1z6Gw)

Title: Re: Help me choosing new Oscilloscope
Post by: TomKatt on February 15, 2023, 05:00:07 pm
I had in the past the DS1054Z unlocked. Recently I've sell it on eBay trying to upgrade my bench.
In general I do not use scope for "fast" signals (I have never measured signals faster than 10MHz) but just for power supplies ripples, data bus, and so on. Never used for any kind of HF application. So my question is, can you help me choosing ?
Just curious - from your description, it would almost seem as though the DS1054Z would have met most of your requirements...  In what ways did you find it lacking enough to sell it and consider upgrading?

Your requirements seem relatively modest, yet your budget and considerations far exceed them?

Edit - of course, you may be like myself and simply always want 'better'...  However, the wife tends to view priorities somewhat differently lol  :P
Title: Re: Help me choosing new Oscilloscope
Post by: nctnico on February 15, 2023, 07:11:24 pm
There are many recent threads about oscilloscopes so there really isn't a good reason to start another one. The  DS1054Z firmware has slowly matured but the newer Rigols seem like a bug-fest needing a couple of years to get fixed.

With the OP's budget I'd take a good look at one of the new, big screen MicSig tablet oscilloscopes.
Title: Re: Help me choosing new Oscilloscope
Post by: bigfede on February 16, 2023, 07:47:32 am
I point out that the screen was pretty small when working with four channels, also the FFT was not readable at all. Also I thought to upgrade in order to be able to do "more". For example: I have a logic analyser that directly connect to my Mac, It's from DreamSourceLab and it works pretty good, I can record and then do some kind of post processing. It happened sometime that I need to have a look at signals in real time, and it was not possible at all! So maybe with the MSO5000 the integrates digital inputs I can finally do that.
Title: Re: Help me choosing new Oscilloscope
Post by: bigfede on February 16, 2023, 07:53:03 am
Ok, but any competitor? I mean I've always used Rigol or Lecroy, but is there any good competitor to this model?

You should check the Siglent SDS2104X Plus, it can be easily hacked to 500MHz and has very low noise front end.

In the EU you can get the SDS2104X+ for ~1199 Euro from “Batter Fly”, link below
https://www.batterfly.com/shop/en/siglent-sds2104x-plus (https://www.batterfly.com/shop/en/siglent-sds2104x-plus)

Check the SDS2104 and MSO5074 side by side review:

https://www.youtube.com/watch?v=93QUNt1z6Gw (https://www.youtube.com/watch?v=93QUNt1z6Gw)


I've seen this video surfing around on YT and I was not sure on my choice. I mean: the Ripon have 8Gsa/S ( :Pthat for the prize is amazing) but Siglent "only" 2..
Title: Re: Help me choosing new Oscilloscope
Post by: tautech on February 16, 2023, 08:13:21 am
I've seen this video surfing around on YT and I was not sure on my choice. I mean: the Ripon have 8Gsa/S ( :Pthat for the prize is amazing) but Siglent "only" 2..
Yes two 2GSa/s ADC's each serving 2 channels and each ADC with 200 Mpts memory depth.
With 4 channels driven SDS2000X Plus provides 1 GSa/s and 100 Mpts max per channel.

Lesson is the big numbers need be broken down to see the full picture.
SDS2000X Plus is a 350 MHz 4ch or 500 MHz 2 channel design depending on how you need to use it.

However, you said the DS1054Z screen was too small for your liking but with a DSO with a webserver you can port the display to a PC display where you won't have any issues with waveforms or FFT being to small.
But this always comes back to needs and available budget.  :popcorn: 
Title: Re: Help me choosing new Oscilloscope
Post by: bigfede on February 16, 2023, 08:47:22 am
I've seen this video surfing around on YT and I was not sure on my choice. I mean: the Ripon have 8Gsa/S ( :Pthat for the prize is amazing) but Siglent "only" 2..
Yes two 2GSa/s ADC's each serving 2 channels and each ADC with 200 Mpts memory depth.
With 4 channels driven SDS2000X Plus provides 1 GSa/s and 100 Mpts max per channel.

Lesson is the big numbers need be broken down to see the full picture.
SDS2000X Plus is a 350 MHz 4ch or 500 MHz 2 channel design depending on how you need to use it.

However, you said the DS1054Z screen was too small for your liking but with a DSO with a webserver you can port the display to a PC display where you won't have any issues with waveforms or FFT being to small.
But this always comes back to needs and available budget.  :popcorn: 

Thanks for your suggestion. My point here is to understand if 8Gsa/s VS 2Gsa/s can make really the difference. I was aware that the front end (Rigol) is pretty noisy.
Title: Re: Help me choosing new Oscilloscope
Post by: tautech on February 16, 2023, 09:24:23 am
My point here is to understand if 8Gsa/s VS 2Gsa/s can make really the difference.
You missed the point as each have their pluses and minuses. Max sample rate is governed by the # of active channels.
Siglent X Plus and many of their other models use 2x ADC's so when all channels are active the resultant sampling rate determines the system BW for it not to break Nyquist.
Typically its 2.5x BW which for 350 MHz requires 1 GSa/s where for the SDS2000X Plus this is met with all channels active.
But by using 2 ADC's BW can be pushed to 500 MHz and still meet Nyquist on the condition just one channel is used on each 2 GSa/s ADC.
This is managed automatically with BW limiters on the X Plus with Full BW when just 2 channels are used or a 350 MHz BW limit is engaged when a 3rd channel or subsequent is activated.

In reality SDS2104X Plus has a 4ch BW of ~185 MHz and SDS2504X Plus nearly 600 MHz with 2 channels active but 350 MHz when a 3rd or 4th is activated.
Title: Re: Help me choosing new Oscilloscope
Post by: BillyO on February 16, 2023, 02:45:10 pm
Your original post says "I do not use scope for "fast" signals (I have never measured signals faster than 10MHz) ".  Now it seem you are hung up on 8Gsa/S vs 2Gsa/S.  Have your requirements changed?

First, teh Rigol is 8Gsa/S only for a single channel, by the time you activate all 4 you are down to 2Gsa/S.

The higher sample rate is only really important for the display more complex HF signals.  The analog BW of the Rigol will ensure those signals are pretty much filtered to a sine wave by the time the 8Gsa/S becomes an important factor.  So I'm really not sure why it is emphasized so much in their marketing.  It's really there because they use a single ADC and they want to have 2Gsa/S with all 4 channels enabled.  That is a minor advantage over the Siglent.  You will, if you need to look at 250MHz +, get a little better signal representation with the Rigol.  However, there a far more advantages in favor of the Siglent over the Rigol in other areas.

You need to decide what is important to you and make your decision on which scope best delivers what you need.  But the 8Gsa/S is not something you can fully realize on the Rigol so it's probably best you don't get too hung up on it.
Title: Re: Help me choosing new Oscilloscope
Post by: bigfede on February 16, 2023, 02:54:13 pm
Your original post says "I do not use scope for "fast" signals (I have never measured signals faster than 10MHz) ".  Now it seem you are hung up on 8Gsa/S vs 2Gsa/S.  Have your requirements changed?

First, teh Rigol is 8Gsa/S only for a single channel, by the time you activate all 4 you are down to 2Gsa/S.

The higher sample rate is only really important for the display more complex HF signals.  The analog BW of the Rigol will ensure those signals are pretty much filtered to a sine wave by the time the 8Gsa/S becomes an important factor.  So I'm really not sure why it is emphasized so much in their marketing.  It's really there because they use a single ADC and they want to have 2Gsa/S with all 4 channels enabled.  That is a minor advantage over the Siglent.  You will, if you need to look at 250MHz +, get a little better signal representation with the Rigol.  However, there a far more advantages in favor of the Siglent over the Rigol in other areas.

You need to decide what is important to you and make your decision on which scope best delivers what you need.  But the 8Gsa/S is not something you can fully realize on the Rigol so it's probably best you don't get too hung up on it.
Thanks, this is the kind of discussion I need to decide.
But now, why Siglent is so much better? Apart that it cost 300€ more.
Title: Re: Help me choosing new Oscilloscope
Post by: Fungus on February 16, 2023, 03:37:19 pm
First, teh Rigol is 8Gsa/S only for a single channel, by the time you activate all 4 you are down to 2Gsa/S.

Sure, but that's not obligatory. You can have 8Gsa/S when you really need it.
Title: Re: Help me choosing new Oscilloscope
Post by: bigfede on February 16, 2023, 05:11:11 pm
First, teh Rigol is 8Gsa/S only for a single channel, by the time you activate all 4 you are down to 2Gsa/S.

Sure, but that's not obligatory. You can have 8Gsa/S when you really need it.
That's my point, if needed the Rigol can satisfy 8Gsa/s! Others costs more and with less feature (eg Rigol have also Function Generator built in)
Title: Re: Help me choosing new Oscilloscope
Post by: bdunham7 on February 16, 2023, 05:33:51 pm
That's my point, if needed the Rigol can satisfy 8Gsa/s! Others costs more and with less feature (eg Rigol have also Function Generator built in)

8GSa/s on a scope without 50R inputs seems somewhat pointless, but the minimum 2GSa/s (4 channels active) with 350MHz BW does mean that it will be much less likely to have aliasing effects.  I doubt that is a serious issue for you, but that's the only real selling point.  I'm all for more samples, but not at the expense of some of the other things the Rigol does not do as well.
Title: Re: Help me choosing new Oscilloscope
Post by: bigfede on February 16, 2023, 06:01:27 pm
That's my point, if needed the Rigol can satisfy 8Gsa/s! Others costs more and with less feature (eg Rigol have also Function Generator built in)

8GSa/s on a scope without 50R inputs seems somewhat pointless, but the minimum 2GSa/s (4 channels active) with 350MHz BW does mean that it will be much less likely to have aliasing effects.  I doubt that is a serious issue for you, but that's the only real selling point.  I'm all for more samples, but not at the expense of some of the other things the Rigol does not do as well.

How about HDO1000?
Title: Re: Help me choosing new Oscilloscope
Post by: TomKatt on February 16, 2023, 06:04:47 pm
I'm all for more samples, but not at the expense of some of the other things the Rigol does not do as well.
Speaking of which - if the way my Siglent SDS1104X-E operates is representative of how modern DSO's work, the scope cuts back on sampling frequency at lower timebases...  So if the you don't really work with high frequencies much, wouldn't you be paying for sampling rates you couldn't use?
Title: Re: Help me choosing new Oscilloscope
Post by: 2N3055 on February 16, 2023, 06:06:26 pm
I'm with Nico here..

This is same again for thousand time same question that was answered so many times before.
To OP:
what do you expect new to hear?  It has been discussed to death..

In that approximate range of MSO scopes there are two scopes Rigol MSO5000 and Siglent SDS2000XPlus.

Rigol is a bit cheaper and Siglent is a bit more expensive. MSO5000 will do the job if you don't need absolutely best analog performance and has few more things: one AWG output  more, more math channels and more decode channels. AWG is limited on both (separate AWG is really the way to go) and math and decode usefulness depends on what you do.
Siglent has better sensitivity and much lower noise, propper FFT implementation, excellent Bode plot implementation, it has only 2 math channels but those you can type arbitrary formula... etc. Each has specific set of strengths and weakneses.

Siglent is generally more refined. To many people MSO5000 will be sufficient. And so will be DS1054Z or Siglent SDS1000X-E..

My advice is to find one of previous endless discussion on this and do your homework. Nobody here actually know what you want, expect, or will do in a future. And it is boring to repeat all the same stuff again and again. Most of the people that could be helpful don't even bother to answer anymore...
Good luck in your quest..

Title: Re: Help me choosing new Oscilloscope
Post by: 2N3055 on February 16, 2023, 06:07:10 pm
That's my point, if needed the Rigol can satisfy 8Gsa/s! Others costs more and with less feature (eg Rigol have also Function Generator built in)

8GSa/s on a scope without 50R inputs seems somewhat pointless, but the minimum 2GSa/s (4 channels active) with 350MHz BW does mean that it will be much less likely to have aliasing effects.  I doubt that is a serious issue for you, but that's the only real selling point.  I'm all for more samples, but not at the expense of some of the other things the Rigol does not do as well.

How about HDO1000?

You said you want MSO. DHO1000/4000 are not MSO. Also to add to sampling discussion, these don't sample at 8GS/s either..
Title: Re: Help me choosing new Oscilloscope
Post by: Sighound36 on February 16, 2023, 06:25:35 pm
If ripple noise  is important buy a picoscope of ther HDO1000. The MSO 5000 is a good all rounder, not as quiet but more flexible and powerful.

Otherwise a Lecroy Wavesurfer HD get the best of both with 5Gs/s
Title: Re: Help me choosing new Oscilloscope
Post by: bigfede on February 16, 2023, 06:58:48 pm
Thanks to all!! Now I'll try to understand where buy it. Apparently the MSO5074 is not stock anywhere.
Title: Re: Help me choosing new Oscilloscope
Post by: BillyO on February 16, 2023, 07:09:51 pm
Sure, but that's not obligatory. You can have 8Gsa/S when you really need it.
If you really need 8Gsa/S then you would also need better than 350MHz analog BW.  Sure, it's there, but can you really get the benefit?
Title: Re: Help me choosing new Oscilloscope
Post by: bigfede on February 16, 2023, 07:30:59 pm
Sure, but that's not obligatory. You can have 8Gsa/S when you really need it.
If you really need 8Gsa/S then you would also need better than 350MHz analog BW.  Sure, it's there, but can you really get the benefit?
This is something that I was thinking about. Does it worth?
Title: Re: Help me choosing new Oscilloscope
Post by: bdunham7 on February 16, 2023, 07:50:32 pm
Basically I'm looking for a valid upgrade. Usually 5mV is sufficient on most of my application.

An additional point here on this subject--5mV may seem 'good enough', but when you factor in using 10X or even 100X probes, the front end noise is amplified proportionally. 
Title: Re: Help me choosing new Oscilloscope
Post by: 2N3055 on February 16, 2023, 08:53:41 pm
Sure, but that's not obligatory. You can have 8Gsa/S when you really need it.
If you really need 8Gsa/S then you would also need better than 350MHz analog BW.  Sure, it's there, but can you really get the benefit?
This is something that I was thinking about. Does it worth?

Short answer, no.  It gives you no benefit in this case..
Title: Re: Help me choosing new Oscilloscope
Post by: JeremyC on February 17, 2023, 01:58:45 am

That's my point, if needed the Rigol can satisfy 8Gsa/s! Others costs more and with less feature (eg Rigol have also Function Generator built in)

8GS/s vs 2GS/s will not matter in described by you cases, but noise level will when you analyze ripples in power supplies.

The 8GS/s (even 4GS/s when 2 channels in use) isn't perfect in the MSO5000 scopes. Check sample rates related link https://www.eevblog.com/forum/testgear/rigol-mso5000-artifacts/ (https://www.eevblog.com/forum/testgear/rigol-mso5000-artifacts/) .
You can't shutdown sin(x)/x interpolation in the Rigol MSO5000 and HDO 12 bit models, for me it was one of few deal breakers.

If you have the choice order both scopes, compare which is matching your needs and send the looser back to the vendor. I don’t know about Amazon in Italy, but in the US returns are free of charge.

Good luck :)
Title: Re: Help me choosing new Oscilloscope
Post by: BillyO on February 17, 2023, 03:57:09 am
My story.

A few months ago I went thought exactly this exercise.

I was in the market for quite an extensive lab upgrade including 2 scopes.  One was a lower end scope and the Siglent 1004X-E series was the clear winner, but I also wanted something that would be at least a full step above that range.

I had a list of things I wanted in a scope.  Bandwidth was high on the list as was low noise.  But I also had other things I leaned towards.  Personal preferences.  After a brief (maybe 2 weeks) scan of the available scopes I narrowed it down to the Rigol (MSO5000) and the Siglent (SDS2000XP).  The price of the Rigol at the time was a real bonus, but my experience with the Siglent 1104X-E was also a great bonus. So .. to break the tie I printed out the full data sheets from both and went through the specs line by line from MY perspective and marked the sheets up with green for good and orange for nah, then  I went with the one that had the most green.  For me that was the Siglent by quite a big margin.

Getting folks' suggestions is a good exercise, but knuckling under and owning up to your personal needs is paramount in making a good decision.  Spending around $1K on a scope should not be a decision left to anonymous folks on the internet.  Do you own diligence.
Title: Re: Help me choosing new Oscilloscope
Post by: Fungus on February 17, 2023, 07:07:58 am
Basically I'm looking for a valid upgrade. Usually 5mV is sufficient on most of my application.
An additional point here on this subject--5mV may seem 'good enough', but when you factor in using 10X or even 100X probes, the front end noise is amplified proportionally.

For the stated use case ("ripple") the probes will be in 1x mode.

Title: Re: Help me choosing new Oscilloscope
Post by: bdunham7 on February 17, 2023, 05:28:59 pm
For the stated use case ("ripple") the probes will be in 1x mode.

If you interpret 'ripple' narrowly to mean only the 50/60/100/120Hz components then maybe.  But if you take the standard method of measuring 'ripple and noise' with a 20MHz BW, then your 3-5MHz 1X probing isn't going to work as well.  On a HF SMPS, I think this will matter.  Even the 20MHz BW seems inadequate to me considering some of the noise I've seen from cheap LED drivers.  In any case, I'm sure my point is generally valid--the way you discover your scope front end is inadequate will most likely be when using 10X or 100X probes.
Title: Re: Help me choosing new Oscilloscope
Post by: CosteC on February 18, 2023, 05:35:02 pm
Thanks to all!! Now I'll try to understand where buy it. Apparently the MSO5074 is not stock anywhere.
It is available here: https://ndn.com.pl/en/digital-oscilloscopes/4397-oscyloskop-cyfrowy-rigol-mso5074-70mhz-4ch-seria-mso5000.html it is official distributor for Poland, shall answer emails in English.

What you miss in DS1054Z? Maybe this way it will be easier to find something suitable.
MSO5000 is rather noisy, but has superb sampling. Still 8 GSps does not seem needed for 10 MHz signals. Even 2 GSps at 4 signals is bit overkill.
MSO5000 is far nicer to operate with large touch screen or mouse connected, but this is available with many more non-basic scopes.
Title: Re: Help me choosing new Oscilloscope
Post by: bigfede on February 19, 2023, 03:55:42 pm
Well I'm thinking to shift to a HDO series instead of MSO, and buying separately a signal generator.
Title: Re: Help me choosing new Oscilloscope
Post by: CosteC on February 19, 2023, 08:09:40 pm
Well I'm thinking to shift to a HDO series instead of MSO, and buying separately a signal generator.
MSO5000 signal generator has very low output range: 5 Vpp in Hi-Z mode, this is very little, too little to drive 3.3 V logic correctly. FY6800, FY6900 generators have better amplitude resolution! There is also whole topic of modulations. Bode ability is however nice feature.
So I think decision to get real signal generator is a wise one.
Title: Re: Help me choosing new Oscilloscope
Post by: smallfreak on April 07, 2023, 01:37:18 pm
I hope you allow me to add my questions to this thread as I'm essentially in the ever same "don't know what to buy" situation that drives the veterans nuts in EVERY forum...   ::)

I lost my previous scope due to a flooding in my basement where the item was stored in a shelf that time. The device was soaked in muddy waters and "dead" afterwards. It was a trusty "all analog" device. Not the top notch finest premium selection, but definitely well beyond entry level. The good thing is, that the insurance agreed to pay for a "suitable replacement". Whereas "suitable" might be arguable, but we agreed that this does not mean the cheapest possible solution to get up to the former nominal specs of the broken one but rather "a current available device from a reputable but not premium brand at a comparable model level".

That brings me in the lucky situation to shop for a scope in the 1k to 1.5k price range that will be usable for "all kind of amateur electronic interest".

I have no ambitions to design satellite communication stuff and I certainly will not have to "tune" my 24bit audio interface at any time. So neither ultra high resolution nor microvolt noise floor nor gigahertz performance is necessary. Since I just use it for my own, a perfectly streamlined user interface is not the primary selection criteria, as long as it does not hamper the overall function. But then, I AM a male and thus not immune to the "Gear Acquisition Syndrome".  :palm:

I DID read a lot the previous weeks, watched the relevant(?) videos and tried to keep up with the thousands of posts here that pick apart each and every miniscule specification and usability quirks - which turned out quite difficult. I settled with the following "knowledge" so far:


What I did not figure out are such things:

While Rigol seems to have more need for bugfixing the software, and it seemingly does this rather slowly, this might still be an option to get a great scope in the end, as long as they DO fix their problems and not declare the device EOL quickly and urge the customers to upgrade to the 2024 model instead "where all is just great". Do they? Have they done in the past? In the old time, things just worked out of the box (or just went back immediately) and kept doing until they really needed some repair. Nowadays all things seem to need permanent and frequent "updates" just to keep them running or ironing out software problems that made it into the release version. I as a hobbyist would accept some release cycles to marture the device as trade in for good overall specifications at a bargain price.

This could nudge me to get an "MSO5074" (+ logic adapter), as I might be able to get that paid fully.

The "SDS2104x Plus" in contrast seems to compet nicely on features, with a better(?) UI but might turn out that I have to add the logic adapter on my own, which likely would not happen at all, as long as I have no urgent need, which might turn out as "never". I had none in the past and I just skipped all projects that would have needed one.

But then, why pick an MSO at all and not one of the DHO1000 models that do fall into the proposed budget too. No MSO, but otherwise fine specs. This is where things start to get complicated again. Trade digital inputs (that I probably not really need) against vertical resolution (that I probably not really need either)? My crystal ball is quite dusty and does not show any future need that could help me deciding.

Ever had the problem to spend other peoples money for a "maximum solution" you don't even know?  |O Splitting the budget into a cheaper scope plus a fancy new SMD soldering station is not part of the insurance contract...

Well, certainly a first-world problem.

I'm open for thoughts.
Title: Re: Help me choosing new Oscilloscope
Post by: Fungus on April 07, 2023, 02:38:53 pm
If the choice is between "Rigol+logic probes" or "Siglent without" then you're on your own. Nobody else knows how likely you are to need the logic stuff.

If you choose the new Rigol HDO1000 it should be for the hi-def screen and awesome user interface. Again, it depends on how much you value that sort of thing.

Bottom line: Don't obsess over the bullet-points and technicalities, it will get you nowhere. None are perfect, all are good value for money, all will be amazing compared to what you had before.

Ever had the problem to spend other peoples money for a "maximum solution" you don't even know?  |O Splitting the budget into a cheaper scope plus a fancy new SMD soldering station is not part of the insurance contract...

Simple answer: Spend as much as possible!

Seems to me like the choices are:
* Logic probes/not
* Next-gen UI/not
* Siglent

Pick your priority.
Title: Re: Help me choosing new Oscilloscope
Post by: 2N3055 on April 07, 2023, 04:25:09 pm
If the choice is between "Rigol+logic probes" or "Siglent without" then you're on your own. Nobody else knows how likely you are to need the logic stuff.

If you choose the new Rigol HDO1000 it should be for the hi-def screen and awesome user interface. Again, it depends on how much you value that sort of thing.

Bottom line: Don't obsess over the bullet-points and technicalities, it will get you nowhere. None are perfect, all are good value for money, all will be amazing compared to what you had before.

Ever had the problem to spend other peoples money for a "maximum solution" you don't even know?  |O Splitting the budget into a cheaper scope plus a fancy new SMD soldering station is not part of the insurance contract...

Simple answer: Spend as much as possible!

Seems to me like the choices are:
* Logic probes/not
* Next-gen UI/not
* Siglent

Pick your priority.

Siglent is next gen GUI with touch screen too. Just different graphic representation. Mac vs Windows type of thing, not Mac vs DOS...
New Rigol GUI is more "graphic-y" and that might have appeal to some. Matter of taste. It looks nice, agree..

New HDO1000 is still very new.. Some stuff is not there yet. It will take time before is mature.. Decent hardware, but still work in progress, more like advanced beta stage...Not a problem long term I presume, but if you need something right now maybe not best solution..

At this point SDS2000X+ is "just works" and "bang for the buck" in it's price range. MSO5000 is a bit cheaper, worse in some regards but good in some other..
HDO1000/4000 is very new and I would wait at least 6 more months to give Rigol time to do it right...
Title: Re: Help me choosing new Oscilloscope
Post by: tautech on April 07, 2023, 08:11:49 pm
smallfreak, an interesting dilemma.  :)

A # of points to add from general knowledge gained here are a little from my crystal ball.  ;)

There is a DIY thread here for LA/MSO probes for the Siglent SDS2kX Plus. It's straightforward to make.
If considering LA/MSO, Rigol HDO1000 does not provide it but after reading again it seems you know that.

From the crystal ball, SDS1000X HD is only a few weeks away if you can wait for it and it will support LA/MSO albeit with a external active module where at this time no DIY is possible.
Recent thread on this series is easy to find and has some more info.
Sorry we can't indicate cost yet.  :(
Title: Re: Help me choosing new Oscilloscope
Post by: Martin72 on April 07, 2023, 11:21:56 pm
That brings me in the lucky situation to shop for a scope in the 1k to 1.5k price range

As mentioned before, there are only a few in that range.
The "old" good known ones, rigol MSO5000 and siglent SDS2000X+ and then the new ones, Rigol DHO1000 and the (currently not avaible) SDS1000X HD.
In my opnion, the two last mentioned got only one (in case of the rigol DHO vs rigol MSO two*) advantage and that´s the 12bit resolution.
Otherwise, you have to keep in mind that the two are slimmed-down versions of their bigger brothers(2000X HD and DHO4000).
So the first decision would be 12 or 8bit... ;)
If the last "wins", there are two models waiting for you(in the pricerange).
Rigol MSO5000 and Siglent SDS2000X+.
I had both... ;)
Personally I would prefer the SDS2000X+ for several reasons I can tell when it´s interesting.
Otherwise a short list of pro/cons based on "hard facts".
Rigol MSO 5000:
+ Max. 8GSa/s
+ 2-Ch AWG
+ HDMI output
+ 4 mathchannels
+ Math: digital filters
- 9" display, slightly dim
- No clear structutured UI
- No 50Ohm inputs
- Noisy frontend
- Still are little bit buggy (but not a kind of showstopping)
- Released 2018, EOL unknown
- Hackable, but after every new firmware update it needs to behacked again
- 350Mhz bandwith max (official)

Siglent SDS2000X+:
+ 10" display, bright and clear
+ Well structured UI
+ 50 Ohms inputs
+ Matured software in general
+ Low noise frontend
+ Hackable and hacks persisting after firmware update
+ Max bandwith up to 500Mhz
- 1-ch AWG with rudimentary functions (but with 50Mhz instead 25Mhz the rigol have)
- 2 Mathchannels
- No video output
- No digital filters in math
- 2GSa/s max

*) The new rigol DHO got a way, way more better UI than the MSO5000 have.



Title: Re: Help me choosing new Oscilloscope
Post by: smallfreak on April 08, 2023, 10:21:28 am
Thank you all for your help. I tried to read all the necessary folowups about the "SDS1000X HD" that might come "soon". Comparing the chinese prices with the European listed prices makes me think that they are at the same level. A simple currency conversion do show a difference of a few bucks only. So I would expect a target price around 900€.

Logic and AWG uses the same external components as the SDS2000X-E series. Doing a rough calculation on that, a "full hardware, no license" pack might settle at 1500€, almost identical with the "SDS2104X Plus" in the same "full hardware no license" configuration. They would differ in

SDS2104X PlusSDS1074X HD
BW10070
BW max500200
Bit812
Samples2G1G
AWG50MHz25MHz

Whereas I'm not sure why anyone would like to buy the external AWG-Option-kit for 234€ when the SDG1032X is just 50 bucks more with WAY better specs.

The MSO5074 is at the same price level, excelling only in the proposed 8G sampling that might have a marginal advantage at the max 350MHz on a single channel.

So far the upcoming SDS1000 HD paired with an SDG1032X instead of the "standard" SAG1021I option seems to be a great package for everything up to 200MHz, if the hidden features can get unlocked cheaply.  ::)
Title: Re: Help me choosing new Oscilloscope
Post by: tautech on April 08, 2023, 10:45:10 am
smallfreak, you presume SDS1074X HD will come to the west when I'm reasonably sure it won't.

Here where I think out loud:
https://www.eevblog.com/forum/testgear/siglent-sds1000x-hd-coming/msg4789955/#msg4789955 (https://www.eevblog.com/forum/testgear/siglent-sds1000x-hd-coming/msg4789955/#msg4789955)
I've compared pricing against the US website SDS2352X-E which in Euro is 729 way less than your 900 Euro.

Certainly your pairing with a SDG1032X is the way to go and it's good to see a prospective buyer knowing the significant benefits of a 2ch standalone AWG vs an inbuilt or USB power module.  :clap:
However something many overlook is SAG1021I is an isolated output AWG and while having basic specs isolation OTOH can be very useful in many applications.

Soon is soon in my book and I can't reveal the intended 1kX HD release date although it's around mid year.  :-X
Title: Re: Help me choosing new Oscilloscope
Post by: smallfreak on April 08, 2023, 01:47:00 pm
smallfreak, you presume SDS1074X HD will come to the west when I'm reasonably sure it won't.
...
I've compared pricing against the US website SDS2352X-E which in Euro is 729 way less than your 900 Euro.
If it's going to get cheaper, I see no problem :-)

If the lowest Euro model turns out to be the "SDS1104X HD between $849 and 999", then it's essentially the same calculation. I just would start at a higher base bandwidth. Reading the discussions, the hardware is assumed to be identical and "software upgradable options" are still the same. So in the end I glimpse at the minimum specs for financing and the maximum specs for usability.

Mid year could pose a problem with the insurance, as they might want close the case when I miss to claim my bill in time. I will talk with the agent after Easter Holidays. Eventually this helps decide between "higher maximum bandwidth" and "higher maximum resolution".

However something many overlook is SAG1021I is an isolated output AWG and while having basic specs isolation OTOH can be very useful in many applications.

Good point. I did miss this. I learned about the advantages of isolated equipment some 40 years ago, when I stuck my soldering iron into the wrong place in a running TV, I was going to repair. It did survive and in the end I could fix the problem (thanks to my very first and very basic scope), but I had to take a break to get my hands calm again and the board had a bad scar.  :palm:

Teenagers tend to do silly things at times.
Title: Re: Help me choosing new Oscilloscope
Post by: Performa01 on April 09, 2023, 10:39:52 am
The MSO5074 is at the same price level, excelling only in the proposed 8G sampling that might have a marginal advantage at the max 350MHz on a single channel.
This is not correct. Signal detail at higher frequencies depends on the input bandwidth, nothing else. So it is a frontend feature only. The sample rate on the other hand has to be twice the max. input frequency in order to satisfy Nyquist.

An ideal acquisition system with ideal AA (anti-aliasing) filter at the input and sin(x)/x (reconstruction) filter at the output would require barely more than twice the input bandwidth as the sample rate. Anything less would not work anymore, but also anything more would be just redundant data, using up additional sample memory without any benefit.

Of course, the (digital) reconstruction filter can only be near ideal because of the limited time interval it is processing. But in practice, we get quite decent reconstruction results with sample rates about 2.5 times the highest frequency component of the input signal.

Up to now, 1 GSa/s would be the correct sample rate for a 350 MHz bandwidth DSO. Anything above that is just a waste of memory.

Unfortunately, we cannot have a strict bandwidth limit in our scope frontends; effective AA-filters aren't going to happen for a number of reasons. Everything we can get in the real world, which does not distort the input signal in an unacceptable way, is fairly ineffective – especially close to the corner frequency.

That means, that a high amount of oversampling gives us the opportunity to apply a benign (e.g. Bessel) AA-filter, which is totally ineffective in the proximity of its corner frequency, but will be sufficiently effective at an adequate distance, hence at the Nyquist frequency of a heavily oversampled signal. On top of that, we can use digital filtering to support the suppression of aliased signals appearing in the region between analog input bandwidth and Nyquist. All in all, we simply trade aliasing protection for memory.


So far the upcoming SDS1000 HD paired with an SDG1032X instead of the "standard" SAG1021I option seems to be a great package for everything up to 200MHz, if the hidden features can get unlocked cheaply.  ::)
Absolutely.

If you ever want a MSO and think about getting this by adding the SLA1016, then you should be aware that this isn't a great solution. It still remains some separate piece of hardware, attached to the scope via a data link with limited speed. The integrated digital channels of the SDS2000X Plus and any higher series are considerably better.
Title: Re: Help me choosing new Oscilloscope
Post by: tggzzz on April 09, 2023, 01:17:36 pm
The MSO5074 is at the same price level, excelling only in the proposed 8G sampling that might have a marginal advantage at the max 350MHz on a single channel.
This is not correct. Signal detail at higher frequencies depends on the input bandwidth, nothing else. So it is a frontend feature only.

Yes.

Quote
The sample rate on the other hand has to be twice the max. input frequency in order to satisfy Nyquist.

No. Or rather the sample rate has to be at least twice the bandwidth of the signal to satisfy Nyquist[1].

I have a 1972 portable scope (which can be stored underwater!) which takes one sample every 75µs (i.e. 13kS/s), and has a bandwidth of >5GHz; it measures risetimes of <0.14ns.

Back in the 80s I used a top-of-the-range HP 1GHz scope, which sampled at 25MS/s.

Nowadays you can see that principle in action in various scopes with modes called various things like Equivalent Time Sampling, and in the mixer of every SDR dongle (multiGHz inputs sampled at ~10MS/s).

[1] Standard interview question... You have an audio signal transmitted on a 10MHz carrier. What is the minimum sampling rate you can use?
Title: Re: Help me choosing new Oscilloscope
Post by: 2N3055 on April 09, 2023, 02:03:00 pm
The MSO5074 is at the same price level, excelling only in the proposed 8G sampling that might have a marginal advantage at the max 350MHz on a single channel.
This is not correct. Signal detail at higher frequencies depends on the input bandwidth, nothing else. So it is a frontend feature only.

Yes.

Quote
The sample rate on the other hand has to be twice the max. input frequency in order to satisfy Nyquist.

No. Or rather the sample rate has to be at least twice the bandwidth of the signal to satisfy Nyquist[1].

I have a 1972 portable scope (which can be stored underwater!) which takes one sample every 75µs (i.e. 13kS/s), and has a bandwidth of >5GHz; it measures risetimes of <0.14ns.

Back in the 80s I used a top-of-the-range HP 1GHz scope, which sampled at 25MS/s.

Nowadays you can see that principle in action in various scopes with modes called various things like Equivalent Time Sampling, and in the mixer of every SDR dongle (multiGHz inputs sampled at ~10MS/s).

[1] Standard interview question... You have an audio signal transmitted on a 10MHz carrier. What is the minimum sampling rate you can use?

Again with that.
Nobody cares for repetitive sampling scopes. We are talking about real time samplings scopes.

And you are wrong: repetitive sampling scopes EFFECTIVE sample rate is defined by 1/t of sampling aperture time and fine resolution timing of taking sample in regards to trigger timing.
Fact that it takes samples sparsely is of no influence to Nyquist.

Real time sampling is same: effective sampling rate is based on effective sampling aperture length, but we can (because technology allows it) take every single sample consecutively in real time. Instead of doing it from thousands of separate trigger events like with repetitively sampling scopes. .

There is a reason nobody cares about repetitive sampling scopes anymore (outside special applications). They are useless for any signal that is not strictly repetitive and autocorrelated..

On your interview question, answer is more than 20 something MS/s. Because you didn't specify you want to down convert RF and extract audio you need to satisfy Nyquist to grab full data...

We are talking about oscilloscopes here, not radio receivers or software radio.... Stop confusing people with ortogonal information...
Title: Re: Help me choosing new Oscilloscope
Post by: tggzzz on April 09, 2023, 03:31:34 pm
The MSO5074 is at the same price level, excelling only in the proposed 8G sampling that might have a marginal advantage at the max 350MHz on a single channel.
This is not correct. Signal detail at higher frequencies depends on the input bandwidth, nothing else. So it is a frontend feature only.

Yes.

Quote
The sample rate on the other hand has to be twice the max. input frequency in order to satisfy Nyquist.

No. Or rather the sample rate has to be at least twice the bandwidth of the signal to satisfy Nyquist[1].

I have a 1972 portable scope (which can be stored underwater!) which takes one sample every 75µs (i.e. 13kS/s), and has a bandwidth of >5GHz; it measures risetimes of <0.14ns.

Back in the 80s I used a top-of-the-range HP 1GHz scope, which sampled at 25MS/s.

Nowadays you can see that principle in action in various scopes with modes called various things like Equivalent Time Sampling, and in the mixer of every SDR dongle (multiGHz inputs sampled at ~10MS/s).

[1] Standard interview question... You have an audio signal transmitted on a 10MHz carrier. What is the minimum sampling rate you can use?

Again with that.
Nobody cares for repetitive sampling scopes. We are talking about real time samplings scopes.

Many many people care about repetitive sampling scopes. One obvious question: if nobody cares, why do all the main manufacturers of professional scopes have modes based upon repetitive sampling? Current Keysight literature (https://www.keysight.com/us/en/assets/7018-01852/application-notes/5989-8794.pdf) answers that :
Quote
Advantages of Equivalent Time Sampling Scopes
•    Lower sampling rate allows higher resolution ADC conversion
•    Wider bandwidth
•    Lower noise floor
•    Lower intrinsic jitter
•    Can include front end optical modules
•    Can achieve solutions at a reduced cost

Note the reduced cost point. Samplers are orders of magnitude cheaper than ADCs with the same resolution.

Another point was given by David Hess: avoiding Gibbs Phenomenon artifacts https://www.eevblog.com/forum/projects/oscilloscopes-what-happened-to-equivalent-time-sampling/msg1781960/#msg1781960 (https://www.eevblog.com/forum/projects/oscilloscopes-what-happened-to-equivalent-time-sampling/msg1781960/#msg1781960)

And another: resolving short time intervals e.g. a 100MHz/3.5ns risetime analogue scope easily resolving <1ns intervals. DSOs use ETS for that. timehttps://www.eevblog.com/forum/projects/oscilloscopes-what-happened-to-equivalent-time-sampling/msg1783850/#msg1783850

I suggest you (re)read that thread.

Quote
And you are wrong: repetitive sampling scopes EFFECTIVE sample rate is defined by 1/t of sampling aperture time and fine resolution timing of taking sample in regards to trigger timing.
Fact that it takes samples sparsely is of no influence to Nyquist.

You are going to have to get your story straight.

First you claim that "nobody is interested in repetitive sampling rates", and then you try to demonstrate that by using a parameter that is mainly relevant to repetitive sampling!

Quote
There is a reason nobody cares about repetitive sampling scopes anymore (outside special applications).

That could only be correct if you were using "special application" to mean "any application I don't personally use". That illustrates more about you than about scopes' capabilities and uses.

Quote
On your interview question, answer is more than 20 something MS/s. Because you didn't specify you want to down convert RF and extract audio you need to satisfy Nyquist to grab full data...

You just failed the interview test.

Provided the sampling aperture is sufficiently small, you only need to capture at, say, 44kS/s. Downsampling is not required.

Quote
We are talking about oscilloscopes here, not radio receivers or software radio.... Stop confusing people with ortogonal information...

I gave examples of high-end professional scopes, and amplified the key points by reference to other technologies based on the same principles.
Title: Re: Help me choosing new Oscilloscope
Post by: 2N3055 on April 09, 2023, 03:58:55 pm
The MSO5074 is at the same price level, excelling only in the proposed 8G sampling that might have a marginal advantage at the max 350MHz on a single channel.
This is not correct. Signal detail at higher frequencies depends on the input bandwidth, nothing else. So it is a frontend feature only.

Yes.

Quote
The sample rate on the other hand has to be twice the max. input frequency in order to satisfy Nyquist.

No. Or rather the sample rate has to be at least twice the bandwidth of the signal to satisfy Nyquist[1].

I have a 1972 portable scope (which can be stored underwater!) which takes one sample every 75µs (i.e. 13kS/s), and has a bandwidth of >5GHz; it measures risetimes of <0.14ns.

Back in the 80s I used a top-of-the-range HP 1GHz scope, which sampled at 25MS/s.

Nowadays you can see that principle in action in various scopes with modes called various things like Equivalent Time Sampling, and in the mixer of every SDR dongle (multiGHz inputs sampled at ~10MS/s).

[1] Standard interview question... You have an audio signal transmitted on a 10MHz carrier. What is the minimum sampling rate you can use?

Again with that.
Nobody cares for repetitive sampling scopes. We are talking about real time samplings scopes.

Many many people care about repetitive sampling scopes. One obvious question: if nobody cares, why do all the main manufacturers of professional scopes have modes based upon repetitive sampling? Current Keysight literature (https://www.keysight.com/us/en/assets/7018-01852/application-notes/5989-8794.pdf) answers that :
Quote
Advantages of Equivalent Time Sampling Scopes
•    Lower sampling rate allows higher resolution ADC conversion
•    Wider bandwidth
•    Lower noise floor
•    Lower intrinsic jitter
•    Can include front end optical modules
•    Can achieve solutions at a reduced cost

Note the reduced cost point. Samplers are orders of magnitude cheaper than ADCs with the same resolution.

Another point was given by David Hess: avoiding Gibbs Phenomenon artifacts https://www.eevblog.com/forum/projects/oscilloscopes-what-happened-to-equivalent-time-sampling/msg1781960/#msg1781960 (https://www.eevblog.com/forum/projects/oscilloscopes-what-happened-to-equivalent-time-sampling/msg1781960/#msg1781960)

And another: resolving short time intervals e.g. a 100MHz/3.5ns risetime analogue scope easily resolving <1ns intervals. DSOs use ETS for that. timehttps://www.eevblog.com/forum/projects/oscilloscopes-what-happened-to-equivalent-time-sampling/msg1783850/#msg1783850

I suggest you (re)read that thread.

Quote
And you are wrong: repetitive sampling scopes EFFECTIVE sample rate is defined by 1/t of sampling aperture time and fine resolution timing of taking sample in regards to trigger timing.
Fact that it takes samples sparsely is of no influence to Nyquist.

You are going to have to get your story straight.

First you claim that "nobody is interested in repetitive sampling rates", and then you try to demonstrate that by using a parameter that is mainly relevant to repetitive sampling!

Quote
There is a reason nobody cares about repetitive sampling scopes anymore (outside special applications).

That could only be correct if you were using "special application" to mean "any application I don't personally use". That illustrates more about you than about scopes' capabilities and uses.

Quote
On your interview question, answer is more than 20 something MS/s. Because you didn't specify you want to down convert RF and extract audio you need to satisfy Nyquist to grab full data...

You just failed the interview test.

Provided the sampling aperture is sufficiently small, you only need to capture at, say, 44kS/s. Downsampling is not required.

Quote
We are talking about oscilloscopes here, not radio receivers or software radio.... Stop confusing people with ortogonal information...

I gave examples of high-end professional scopes, and amplified the key points by reference to other technologies based on the same principles.

Omg...
Title: Re: Help me choosing new Oscilloscope
Post by: williamlee on April 09, 2023, 04:03:19 pm
Is it because 99.9% of oscilloscope user doesn`t need the "eye diagram"? so, the sampling rate is quite ok for 1G or 2G?   
The "real-time" still belongs to the analog scope, right? why does the digital scope need the "sampling rate"? because of the "ADC"?
My point of view that MSO5000 is the best C/P value for 90% of applications especially for logic is better value. It makes sure that SDS2000XP also good for the C/P value.  ;D ;D

If MSO5000 has 50-ohm support and the same frond-end which is like 1054z......
If SDS2000XP has 4G sa/S......
If the R/S, Tek, and LeCroy prices are very very close to Rigol and Siglent ...... too many dreams |O :-DD
Title: Re: Help me choosing new Oscilloscope
Post by: tggzzz on April 09, 2023, 04:42:16 pm
The MSO5074 is at the same price level, excelling only in the proposed 8G sampling that might have a marginal advantage at the max 350MHz on a single channel.
This is not correct. Signal detail at higher frequencies depends on the input bandwidth, nothing else. So it is a frontend feature only.

Yes.

Quote
The sample rate on the other hand has to be twice the max. input frequency in order to satisfy Nyquist.

No. Or rather the sample rate has to be at least twice the bandwidth of the signal to satisfy Nyquist[1].

I have a 1972 portable scope (which can be stored underwater!) which takes one sample every 75µs (i.e. 13kS/s), and has a bandwidth of >5GHz; it measures risetimes of <0.14ns.

Back in the 80s I used a top-of-the-range HP 1GHz scope, which sampled at 25MS/s.

Nowadays you can see that principle in action in various scopes with modes called various things like Equivalent Time Sampling, and in the mixer of every SDR dongle (multiGHz inputs sampled at ~10MS/s).

[1] Standard interview question... You have an audio signal transmitted on a 10MHz carrier. What is the minimum sampling rate you can use?

Again with that.
Nobody cares for repetitive sampling scopes. We are talking about real time samplings scopes.

Many many people care about repetitive sampling scopes. One obvious question: if nobody cares, why do all the main manufacturers of professional scopes have modes based upon repetitive sampling? Current Keysight literature (https://www.keysight.com/us/en/assets/7018-01852/application-notes/5989-8794.pdf) answers that :
Quote
Advantages of Equivalent Time Sampling Scopes
•    Lower sampling rate allows higher resolution ADC conversion
•    Wider bandwidth
•    Lower noise floor
•    Lower intrinsic jitter
•    Can include front end optical modules
•    Can achieve solutions at a reduced cost

Note the reduced cost point. Samplers are orders of magnitude cheaper than ADCs with the same resolution.

Another point was given by David Hess: avoiding Gibbs Phenomenon artifacts https://www.eevblog.com/forum/projects/oscilloscopes-what-happened-to-equivalent-time-sampling/msg1781960/#msg1781960 (https://www.eevblog.com/forum/projects/oscilloscopes-what-happened-to-equivalent-time-sampling/msg1781960/#msg1781960)

And another: resolving short time intervals e.g. a 100MHz/3.5ns risetime analogue scope easily resolving <1ns intervals. DSOs use ETS for that. timehttps://www.eevblog.com/forum/projects/oscilloscopes-what-happened-to-equivalent-time-sampling/msg1783850/#msg1783850

I suggest you (re)read that thread.

Quote
And you are wrong: repetitive sampling scopes EFFECTIVE sample rate is defined by 1/t of sampling aperture time and fine resolution timing of taking sample in regards to trigger timing.
Fact that it takes samples sparsely is of no influence to Nyquist.

You are going to have to get your story straight.

First you claim that "nobody is interested in repetitive sampling rates", and then you try to demonstrate that by using a parameter that is mainly relevant to repetitive sampling!

Quote
There is a reason nobody cares about repetitive sampling scopes anymore (outside special applications).

That could only be correct if you were using "special application" to mean "any application I don't personally use". That illustrates more about you than about scopes' capabilities and uses.

Quote
On your interview question, answer is more than 20 something MS/s. Because you didn't specify you want to down convert RF and extract audio you need to satisfy Nyquist to grab full data...

You just failed the interview test.

Provided the sampling aperture is sufficiently small, you only need to capture at, say, 44kS/s. Downsampling is not required.

Quote
We are talking about oscilloscopes here, not radio receivers or software radio.... Stop confusing people with ortogonal information...

I gave examples of high-end professional scopes, and amplified the key points by reference to other technologies based on the same principles.

Omg...

A revealing response to the technical points.
Title: Re: Help me choosing new Oscilloscope
Post by: tggzzz on April 09, 2023, 05:07:07 pm
Is it because 99.9% of oscilloscope user doesn`t need the "eye diagram"? so, the sampling rate is quite ok for 1G or 2G?   
The "real-time" still belongs to the analog scope, right? why does the digital scope need the "sampling rate"? because of the "ADC"?
My point of view that MSO5000 is the best C/P value for 90% of applications especially for logic is better value. It makes sure that SDS2000XP also good for the C/P value.  ;D ;D

If MSO5000 has 50-ohm support and the same frond-end which is like 1054z......
If SDS2000XP has 4G sa/S......
If the R/S, Tek, and LeCroy prices are very very close to Rigol and Siglent ...... too many dreams |O :-DD

There is indeed a lot of overlap in the capability of different classes of instrument. A good engineer knows not only how to use each tool to its best advantage, but also where a tool is insufficient and a different tool should be used.

Where digital systems are concerned, often a scope isn't the best tool. Once a scope has been used to ensure signal integrity[1], often it is better to flip into the digital signal domain by using logic analysers, protocol analysers, and printf() statements.

That's particularly true with low-end scopes, some of which I'm told only process what's on the screen and ignore all the captured information that's off the screen. Even very cheap (<<cost of a scope) logic analysers and protocol analysers can produce better results.

As for cost, new modern scopes cannot be afforded by many individuals. Nonetheless, good Tek/HP scopes (and other tools) are available at remarkably low prices, and - in conjunction with other tools - be used for many complex cases. (Examples: I get 350MHz Tek scopes for £50, 21GHz HP/Tek Spectrum Analysers for £350, and bus pirate protocol analysers and generic logic analysers cost ~£30)

[1] i.e. to ensure the analogue waveform will be correctly interpreted by the receiver as a digital signal. A classic tool to do that is, of course, the eye diagram.
Title: Re: Help me choosing new Oscilloscope
Post by: Performa01 on April 09, 2023, 05:14:36 pm
Quote
The sample rate on the other hand has to be twice the max. input frequency in order to satisfy Nyquist.

No. Or rather the sample rate has to be at least twice the bandwidth of the signal to satisfy Nyquist[1].
So you are saying "no", only to use the following sentence to repeat what I said in slightly different words?

Oh – did I forget to say "at least"? In a statement where I wanted to stress the fact that oversampling doesn't provide any additional information?

And what is the difference between "max. input frequency" and "bandwidth of  the signal"? There is only a difference if we presume that we're not interested in the entire input signal, but only a part of it [1] – which certainly would not be a standard use case.


I have a 1972 portable scope (which can be stored underwater!) which takes one sample every 75µs (i.e. 13kS/s), and has a bandwidth of >5GHz; it measures risetimes of <0.14ns.

Back in the 80s I used a top-of-the-range HP 1GHz scope, which sampled at 25MS/s.

Nowadays you can see that principle in action in various scopes with modes called various things like Equivalent Time Sampling, and in the mixer of every SDR dongle (multiGHz inputs sampled at ~10MS/s).
And what has this to do with the topic discussed here? The equivalent sample rate has to satisfy Nyquist no matter what. And thankfully, nobody has to resort to the ETS crouch for bandwidths up to a couple of GHz anymore nowadays.


[1] Standard interview question... You have an audio signal transmitted on a 10MHz carrier. What is the minimum sampling rate you can use?
Funny that you feel like asking that question in reply to my post of all things.

[1] I have demonstrated several times, how to analyze narrowband signals by means of down-conversion by undersampling, e.g. here:

https://www.eevblog.com/forum/testgear/siglent-sds2000x-hd-12bit-(published-for-chinese-domestic-market-only)/msg4320658/#msg4320658 (https://www.eevblog.com/forum/testgear/siglent-sds2000x-hd-12bit-(published-for-chinese-domestic-market-only)/msg4320658/#msg4320658)


… so what was the intention of your reply? Just to say "no" … or did you want to add some confusion for those who are less familiar with modern DSOs?

Title: Re: Help me choosing new Oscilloscope
Post by: nctnico on April 09, 2023, 05:29:32 pm
Is it because 99.9% of oscilloscope user doesn`t need the "eye diagram"? so, the sampling rate is quite ok for 1G or 2G?   
The "real-time" still belongs to the analog scope, right? why does the digital scope need the "sampling rate"? because of the "ADC"?
My point of view that MSO5000 is the best C/P value for 90% of applications especially for logic is better value. It makes sure that SDS2000XP also good for the C/P value.  ;D ;D
In the end neither a good allround tools though.

Quote
If the R/S, Tek, and LeCroy prices are very very close to Rigol and Siglent ...
then the latter would offer you good allround tools like the A brands. Engineering takes time which equates to money and thus their products will cost the same. Just note how Siglent oscilloscope prices keep going up with the number of features they add. While Rigol keeps competing on prices and releases half baked products hoping the revenue might pay for ongoing engineering efforts (or not). The differentiation is all in firmware / software, the hardware costs are pretty much the same for all manufacturers.
Title: Re: Help me choosing new Oscilloscope
Post by: porter on April 09, 2023, 05:30:29 pm
Too bad that Keysight and Tektronix oscilloscpes are no longer part of these discussions.
Title: Re: Help me choosing new Oscilloscope
Post by: Martin72 on April 09, 2023, 05:32:01 pm
A nice short summary/explanation about the different types of sampling in DSOs (or DPOs) we can find here:

XYZs of Oscilloscopes from Tektronix (https://download.tek.com/document/03W_8605_7_HR_Letter.pdf)

(It´s a pdf)
Title: Re: Help me choosing new Oscilloscope
Post by: Martin72 on April 09, 2023, 05:32:55 pm
Too bad that Keysight and Tektronix oscilloscpes are no longer part of these discussions.

In the mentioned pricerange it makes the same sense as talking about lecroy scopes.
Title: Re: Help me choosing new Oscilloscope
Post by: nctnico on April 09, 2023, 05:34:16 pm
Too bad that Keysight and Tektronix oscilloscpes are no longer part of these discussions.
That is mainly because they don't have many products in the US $1000 price range that aren't cut down too much. Still, in a professional setting I'd buy an A brand oscilloscope (and many other types of complex equipment) any time of the day.
Title: Re: Help me choosing new Oscilloscope
Post by: tggzzz on April 09, 2023, 05:44:25 pm
Quote
The sample rate on the other hand has to be twice the max. input frequency in order to satisfy Nyquist.

No. Or rather the sample rate has to be at least twice the bandwidth of the signal to satisfy Nyquist[1].
So you are saying "no", only to use the following sentence to repeat what I said in slightly different words?

Oh – did I forget to say "at least"? In a statement where I wanted to stress the fact that oversampling doesn't provide any additional information?

And what is the difference between "max. input frequency" and "bandwidth of  the signal"? There is only a difference if we presume that we're not interested in the entire input signal, but only a part of it [1] – which certainly would not be a standard use case.

The difference, as I'm sure you are aware, is that the "signal" needs to be carefully defined when considering the Nyquist frequency. See the audio on 10MHz carrier example :)

Beginners often don't understand the difference, and too often experienced people don't either - as we've seen in this thread!

Quote
I have a 1972 portable scope (which can be stored underwater!) which takes one sample every 75µs (i.e. 13kS/s), and has a bandwidth of >5GHz; it measures risetimes of <0.14ns.

Back in the 80s I used a top-of-the-range HP 1GHz scope, which sampled at 25MS/s.

Nowadays you can see that principle in action in various scopes with modes called various things like Equivalent Time Sampling, and in the mixer of every SDR dongle (multiGHz inputs sampled at ~10MS/s).
And what has this to do with the topic discussed here? The equivalent sample rate has to satisfy Nyquist no matter what. And thankfully, nobody has to resort to the ETS crouch for bandwidths up to a couple of GHz anymore nowadays.

Last week there was an old 1GHz Tek scope auctioned. It went for £1250+35%, which is out of my range. So, yes, some of us do have to resort to ETS - and with skill and imagination we manage to find ways to achieve our ends with tools that many regard as "inadequate".

Quote
[1] Standard interview question... You have an audio signal transmitted on a 10MHz carrier. What is the minimum sampling rate you can use?
Funny that you feel like asking that question in reply to my post of all things.

[1] I have demonstrated several times, how to analyze narrowband signals by means of down-conversion by undersampling, e.g. here:

https://www.eevblog.com/forum/testgear/siglent-sds2000x-hd-12bit-(published-for-chinese-domestic-market-only)/msg4320658/#msg4320658 (https://www.eevblog.com/forum/testgear/siglent-sds2000x-hd-12bit-(published-for-chinese-domestic-market-only)/msg4320658/#msg4320658)

… so what was the intention of your reply? Just to say "no" … or did you want to add some confusion for those who are less familiar with modern DSOs?

To point out that the number of samples/second is a relatively unimportant metric of a scope's performance and usefulness. As you know, front end bandwidth is far more important.

But too many beginners (and apparently experienced people) focus on the sampling rate and think that 1GS/s is automatically better than 250MS/s. My examples are designed to highlight the orthogonality of Hz and S/s.
Title: Re: Help me choosing new Oscilloscope
Post by: nctnico on April 09, 2023, 05:47:37 pm
But too many beginners (and apparently experienced people) focus on the sampling rate and think that 1GS/s is automatically better than 250MS/s.
For a general purpose oscilloscope used for measurements up to 200 to 300 MHz that is simply true. Any reasonable new DSO you can buy nowadays supports at least 1Gs/s for at least 1 channel. Beyond that you can start to weigh things like budget versus requirements but at that point you are looking at measurements that are more specialistic.
Title: Re: Help me choosing new Oscilloscope
Post by: wasedadoc on April 09, 2023, 06:48:37 pm
Standard interview question... You have an audio signal transmitted on a 10MHz carrier. What is the minimum sampling rate you can use?
Standard answer from final year university student. "We haven't done that yet." How many times did I hear that in response to questions?
Title: Re: Help me choosing new Oscilloscope
Post by: 2N3055 on April 09, 2023, 06:53:37 pm

A revealing response to the technical points.


I agree. Your post is exactly that.. Good point there...  Hence OMG... because I have nothing else to say to your endless patronizing us with wrong points...
I know what sampling scopes are, how they work and what are they used for.

That whole topic is IRRELEVANT to discussion which REAL time sampling scope in entry level price range is best choice for OP.. We don't care for another incorrect lecture about sampling scopes...

And I'm going to repeat: To look at 10 MHz modulated signal you need to obey Nyquist and sample at more than twice the frequency of highest frequency in a signal. That is 10MHz here (plus a bit more for sidebands)...  So something about 25MS/s or up...
Your questions begs that answer.

If you weren't try to be smartarse you wouldn't ask a smartarse "trick question" but a one that is technically and factually correct.
If you wanted and answer to "how can you extract audio signal from 10 MHz carrier and what sampling rate is sufficient for that" than ask that..
Idiotic questions get stupid answers....
Title: Re: Help me choosing new Oscilloscope
Post by: smallfreak on April 10, 2023, 05:32:30 pm
It's quite interesting how my half thought comment about the probably limited use of massive oversampling did result in a well of hardcore information about that topic  8)
Lot' to learn from here, once I picked it all apart.

Provided the sampling aperture is sufficiently small, you only need to capture at, say, 44kS/s. Downsampling is not required.

My limited knowledge about that is, that this only applies to a bandwidth limited signal of this maximum frequency. So you probably imply that this audio signal is passed through a 22KHz bandpass filter before sampling - which essentially gets rid of the 10MHz carrier/noise anyway.

I always like to refer to Monty Montgomerys great video about AD/DA and "stairsteps do not exist" (http://"https://www.youtube.com/watch?v=cIQ9IXSUzuM&list=PLjFD_9vRPUKZUg_IztAKVRAOKh55jGq8-").

I did read quite a lot here the last view days and I stumbled across quite some pictures showing a really BAD representation of "actual waveforms" near the upper bandwidth. Likely random zigzag due to idiotically drawing straight lines between the measured points. Unfortunately I was unable to find them again quickly. This have been real screenshots of the scopes in the current 1k-1.5K range. I'm sure you all know what I mean. Maybe the scopes DO support better rendering and the people doing the screenshots simply didn't know or care.

Programmers rendering signal sample points that way should be - er - corrected. There are MUCH better ways to interpolate the values between these points that more likely show the "probably true signal within the given bandwith". Before someone renders straight lines, it's better to just display the points without any interpolation.  |O It's not that much better than the "stairsteps" representation.

Maybe that was a cheap way to overcome the problem that the vertical resolution of the screen is much greater than the vertical resolution of the common 8Bit scope. But this interpolation does not have to be done in real time at 500 MHz, but in "screen time" and just for the displayed samples. In case of hold-mode any cheap processor should be able to do this calculation without notable delay.  :-\

That made me think about the 8Bit sampling resolution again. I still have a tiny DSO112A pocket scope. This too has "8bit resolution" but that does fit well with the equally tiny screen. You don't expect much from such a device. Having to fill a 10" hi-res display with the same number of samples you certainly have to do some visual tricks to NOT make the scope look like a toy.
Title: Re: Help me choosing new Oscilloscope
Post by: tggzzz on April 10, 2023, 06:20:11 pm
Lot' to learn from here, once I picked it all apart.
...
So you probably imply that this audio signal is passed through a 22KHz bandpass filter before sampling - which essentially gets rid of the 10MHz carrier/noise anyway.

If you put a 20kHz audio signal on a 10MHz carrier, all the energy is between (roughly!) 9.98MHz and 10.02MHz. Putting that into a 10MHz+-20kHz bandpass filter changes nothing; the carrier and signal are still there. Put it into a 0-20kHz filter, and you will get nothing out :)

Quote
That made me think about the 8Bit sampling resolution again. I still have a tiny DSO112A pocket scope. This too has "8bit resolution" but that does fit well with the equally tiny screen. You don't expect much from such a device. Having to fill a 10" hi-res display with the same number of samples you certainly have to do some visual tricks to NOT make the scope look like a toy.

Firstly beware of "raw" number-of-bits figures. ADCs are subtle beasts, and ENOB (effective number of bits) is a better measure of performance. Any decent scope specification will include that.

Even if you can't see all the bits on a screen, too few bits can still cause artifacts. That is particularly noticeable if you look at the frequency domain version of the captured waveform, by doing an FFT. Too few bits will be visible as worse harmonics and increased noise floor.

BTW, it is good to see someone reading and thinking - that's a necessary starting point :) Not everybody manages it :(

Once you have gone around the loops of conceptual understanding a few times, you will begin to see that samplers and mixers can perform similar functions - not only in terms of mathematic operations, but also in electronic circuits. Not everyone persists enough to reach that level of understanding and see the beauty.

Have fun.
Title: Re: Help me choosing new Oscilloscope
Post by: Fungus on April 10, 2023, 07:10:22 pm
I did read quite a lot here the last view days and I stumbled across quite some pictures showing a really BAD representation of "actual waveforms" near the upper bandwidth. Likely random zigzag due to idiotically drawing straight lines between the measured points. Unfortunately I was unable to find them again quickly.

Recent posts or old posts?
Title: Re: Help me choosing new Oscilloscope
Post by: 2N3055 on April 10, 2023, 08:00:54 pm
Lot' to learn from here, once I picked it all apart.
...
So you probably imply that this audio signal is passed through a 22KHz bandpass filter before sampling - which essentially gets rid of the 10MHz carrier/noise anyway.

If you put a 20kHz audio signal on a 10MHz carrier, all the energy is between (roughly!) 9.98MHz and 10.02MHz. Putting that into a 10MHz+-20kHz bandpass filter changes nothing; the carrier and signal are still there. Put it into a 0-20kHz filter, and you will get nothing out :)

Quote
That made me think about the 8Bit sampling resolution again. I still have a tiny DSO112A pocket scope. This too has "8bit resolution" but that does fit well with the equally tiny screen. You don't expect much from such a device. Having to fill a 10" hi-res display with the same number of samples you certainly have to do some visual tricks to NOT make the scope look like a toy.

Firstly beware of "raw" number-of-bits figures. ADCs are subtle beasts, and ENOB (effective number of bits) is a better measure of performance. Any decent scope specification will include that.

Even if you can't see all the bits on a screen, too few bits can still cause artifacts. That is particularly noticeable if you look at the frequency domain version of the captured waveform, by doing an FFT. Too few bits will be visible as worse harmonics and increased noise floor.

BTW, it is good to see someone reading and thinking - that's a necessary starting point :) Not everybody manages it :(

Once you have gone around the loops of conceptual understanding a few times, you will begin to see that samplers and mixers can perform similar functions - not only in terms of mathematic operations, but also in electronic circuits. Not everyone persists enough to reach that level of understanding and see the beauty.

Have fun.

All you said here is absolutely true. If you connect 10MHz carrier AM modulated with 20 kHz audio signal all your energy will be around carrier.  And you can see that nicely if you connect that signal to spectrum analyser, you will see that clearly... If you connect it to a CRT analog scope you will see  10 MHz signal varying in amplitude.....  And in order to see exactly the same image on digital scope you need to sample in such manner that your effective sampling rate should satisfy Nyquist  for 10Mhz and a bit more (to account for modulation), so roughly lets say a 25 MS/s or more would be OK number...

If audio signal was single 20Khz tone, you could use old repetitive sampling scope, that should have sampling aperture at faster than  40 ns (1/25M samples per second) and you could take single samples from thousands of separate trigger events by varying time where you take sample in time in regards to trigger point and reconstruct on screen same thing you would see on realtime digital scope sampling at real 25 MS/s because your effective sampling rate would also be 25 MS/s. Nyquist happy.

On the other hand if you where looking at the signal that had any variation in modulation signal ( a voice or music instead of single 20 kHz tone) than you need to use realtime sampling scope that has sufficient BW to capture full signal which is 10 MHz or analog scope.... Repetitive sampling scope will show crap..

There is no place whatsoever mentioning RF samplers and mixers in a discussions about realtime digital scopes. It is a out of topic, by a mile.. We might as well speak about gardening when someone asks a question about scopes....


And by this I don't mean RF samplers and mixers are not fascinating subject and that you obviously know quite a lot about it. Quite a lot. It's just it is off the topic here.
Title: Re: Help me choosing new Oscilloscope
Post by: smallfreak on April 10, 2023, 09:58:00 pm
Recent posts or old posts?

If I find them again, I will take note of that. It could well be it was off site. I've seen a couple of YT videos on the scopes in my shortlist. Not everyone did make the impression to be a real scope specialist. But even if they just did not know how to configure it right, I still was amazed, that any reputable manufacturer would even allow for such a crappy display. I don't want to blame a particular model. But it was more than once, so I maybe wrongly assumed that it is more common.

It also might have been enhanced by a later firmware update however. Unfortunately many tests, videos or just "unboxing of ..." are not always kept up to date with "problems already fixed". It's even quite difficult to find such information here. It might be hidden in "4000+ folloups".  ???

Perhaps a different situation, but maybe I might refer to this pretty recent post of an obviously knowledgeable person (http://"https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg4773941/#msg4773941"). The screenshot probably shows "raw data samples connected by lines" and not what I would recognize as a "true signal reconstructed from data points within bandwidth". Although it is a single shot and no average. At 20ns/div I would expect overshoots on the edges and a much smoother top, even with 250MHz bandwidth and 1GS/s. The measurements certainly do have signal noise and at least 1Bit digitizing noise but that shouldn't necessarily get translated into a jaggy line showing edges and corners way beyond the bandwidth. There is no thing like "corners" in signals.

While these data points might have been measured just so, they most likely have to get correlated first to get a better representation of the underlying true signal they had sampled - which than may take advantage of a higher vertical resolution than the 256 different discrete values an 8Bit digitizer might collect. Maybe the scopes CAN do that, but nobody uses such a function for certain reasons. I know that it can be done on modern scopes for multiple waveforms in a greyscale or color manner to smooth out statistical variations.

I have not yet found a suitable discussion that/why this might be the only viable method of displaying the samples, but I still have a few thousands of Posts to read.  ::) But I do believe I have not seen a "reconstructed signal" so far on any DSO topic.

Being mostly analog with my measurements so far, I might have to get used to different expectations in the DSO world.
Title: Re: Help me choosing new Oscilloscope
Post by: 2N3055 on April 10, 2023, 11:01:13 pm
There are many very good documents on that particular topic, interpolation. There are many thing that we have to read, YT is not everything there is. Quite the opposite..

For instance:
https://cdn.teledynelecroy.com/files/whitepapers/wp_interpolation_102203.pdf

Keysight and Tektronix have similar info.
Title: Re: Help me choosing new Oscilloscope
Post by: tggzzz on April 10, 2023, 11:02:07 pm
...I've seen a couple of YT videos on the scopes in my shortlist....Unfortunately many tests, videos or just "unboxing of ..." are not always kept up to date with "problems already fixed".

There are far too many yoootooob vids like that, on all subjects. I spend ~30s deciding whether an written article is worth spending 10min reading and understanding. Since that is impossible with a yoootooob vid, I ignore them completely unless there is good reason for me to believe they are worth my time. 99.9% aren't!

Quote
Perhaps a different situation, but maybe I might refer to this pretty recent post of an obviously knowledgeable person (http://"https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg4773941/#msg4773941"). The screenshot probably shows "raw data samples connected by lines" and not what I would recognize as a "true signal reconstructed from data points within bandwidth". Although it is a single shot and no average. At 20ns/div I would expect overshoots on the edges and a much smoother top, even with 250MHz bandwidth and 1GS/s. The measurements certainly do have signal noise and at least 1Bit digitizing noise but that shouldn't necessarily get translated into a jaggy line showing edges and corners way beyond the bandwidth. There is no thing like "corners" in signals.

Ah, but how should you choose to interpolate or "join the sample dots"? With a zero order hold, or a first order hold, or ..., or a sinc(x) function, or what? One of my old scopes even allows you to choose.

While that isn't too important for the cases where the sampling rate is much higher than the bandlimited signal being displayed, it is important in other cases. I've seen relatively modern HP scopes (HP54621) where that was a problem when using an infinite persistance mode to examine the signal integrity of a digital waveform's risetime. You could turn off interpolation deep inside the menuing system, but touch any basic control and interpolation re-appeared.

My preference is to see the individual samples as dots, without lines connecting the samples. That way you can see what has and has not been measured.
Title: Re: Help me choosing new Oscilloscope
Post by: Performa01 on April 11, 2023, 09:14:36 am
Perhaps a different situation, but maybe I might refer to this pretty recent post of an obviously knowledgeable person (http://"https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg4773941/#msg4773941"). The screenshot probably shows "raw data samples connected by lines" and not what I would recognize as a "true signal reconstructed from data points within bandwidth". Although it is a single shot and no average. At 20ns/div I would expect overshoots on the edges and a much smoother top, even with 250MHz bandwidth and 1GS/s. The measurements certainly do have signal noise and at least 1Bit digitizing noise but that shouldn't necessarily get translated into a jaggy line showing edges and corners way beyond the bandwidth. There is no thing like "corners" in signals.
Clicking the link doesn't work for me and if I copy the stripped link into the browser, I'm landing at reply #2353 which doen't contain any screenshot.

So I assume you are referring to reply #2356. I do not know about the settings – but that is what you get on an (only) 8-bit scope, where each sample is represented by a line that is 2 screen-pixels high. The signal is slow (10 MHz), obviously noisy and I honestly don't know how BillyO managed to show a single frame even though the DSO says "Trig'd" (1). Normally, we see hundreds or even thousands of acquisitions (records) mixed together in a single frame, 60 times per second – except when in Stop mode, where only the most recent record is shown. The rest is in the history.

How do you know it is linear interpolation? I don't think so – even though it would be the most appropriate display mode for digital (square) signals. When looking close, we just see the granular noise of +/-1 sample, which is represented by +/-2 pixels on the screen. Absolutely no way to determine which interpolation method was used. Furthermore, there are 280 points (samples) in this screen, hence not much need for interpolation.

And why would you expect overshoots at the edges? How can you know what the original signal looks like? Only crappy oscilloscope frontends produce a lot of overshooting on a clean square wave. And I assume that BillyO used a clean signal for testing his "improved" scope…

And "a jaggy line showing edges and corners way beyond the bandwidth": the granular noise of an ADC stems from the sample rate, not the frontend, hence the input bandwidth is irrelevant. One horizontal division represents 20 ns. I cannot see more than 20 different levels within one division, so this would be perfectly plausible for 1 GSa/s and a granular noise of +/-1 LSB.

Here are a few examples how fast signals at short time bases look like with a proper setup, so we can benefit from the SPO technology:

First a 400 MHz sine, vastly exceeding the bandwidth of the 300 MHz DSO (Siglent SDS2304X back in 2016), demonstrating its measurement capabilities (and accuracy). This is about time resolution, but also nicely demonstrates signal reconstruction. Only 1 ns/div and 28 points record length, reply #68:

https://www.eevblog.com/forum/testgear/will-keysight-upgrade-the-2000-3000t-x-series-oscilloscopes-within-a-few-months/msg1029057/#msg1029057 (https://www.eevblog.com/forum/testgear/will-keysight-upgrade-the-2000-3000t-x-series-oscilloscopes-within-a-few-months/msg1029057/#msg1029057)

Then a modulated signal in Dots mode (SDS1104X-E, 2017), to demonstrate that interpolation or reconstruction aren't even necessary in most cases, guaranteeing the best signal fidelity of all methods. This was about a different behavior on signal drop out in normal trigger mode, which I found fine back then, but Siglent have altered it in later firmware to be more mainstream. 50 ns/div, dots mode; reply #341:

https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg1359013/#msg1359013 (https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg1359013/#msg1359013)

Finally a number of square waves at 10 ns/div (SDS1202X-E, SDS2304X, 2018), clearly demonstrating how noticable the difference between a 200 and 300 MHz scope can be in certain situations (the actual bandwidth of the SDS2304X is up to 450 MHz, depending on the probes), reply #515:

https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg1433299/#msg1433299 (https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg1433299/#msg1433299)


While these data points might have been measured just so, they most likely have to get correlated first to get a better representation of the underlying true signal they had sampled - which than may take advantage of a higher vertical resolution than the 256 different discrete values an 8Bit digitizer might collect. Maybe the scopes CAN do that, but nobody uses such a function for certain reasons. I know that it can be done on modern scopes for multiple waveforms in a greyscale or color manner to smooth out statistical variations.
In contemporary Siglent machines we get the original raw data when using normal acquisition and dots display mode. Only when the timebase gets so slow that the scope cannot maintain the full sample rate anymore, then the input sample rate gets decimated after the fact, but the remaining samples are still unmodified.

Decimation algorithm is different when using Peak Detect, which also destroys the signal integrity hence is a mode only for tinkerers or service techs, but not for people who want to do serious signal analysis. Thankfully, the deep memory of modern DSOs vastly reduces the situations, where peak detect would be useful.

There are more acquisition modes, like Average and ERES, both modifying the original samples. The SDS2000X Plus implements these modes as math functions, so we can use them while still preserving the original data. Better scopes (starting from SDS2000X HD) offer both (Average and ERES as acquisition modes and math functions) at the same time.

Like the acquisition modes, we can select the display modes: raw dots, linear interpolation or sin(x)/x reconstruction.

Without decimation, all samples make it to the screen, used for intensity or color grading, as especially the modulation example above should have revealed already.

I have not yet found a suitable discussion that/why this might be the only viable method of displaying the samples, but I still have a few thousands of Posts to read.  ::) But I do believe I have not seen a "reconstructed signal" so far on any DSO topic.
Regarding a discussion about "reconstruction", may I recommend this review, where this topic (and many more) are discussed in great detail, with lots of screenshots for demonstration.
 
https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review (https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review)


Being mostly analog with my measurements so far, I might have to get used to different expectations in the DSO world.
This was certainly true in the last century, where DSOs really left much to be desired and analog engineers mistrusted them. Slow sample rates, short memories, the attempt, to overcome this with ETS, which works only for stably triggered periodic signals – but for longer periods, the scope also needs more memory – and sin(x)/x reconstruction was indeed not so common, because the lack of computation power …

Nowadays Analog engineers can get perfectly happy with the contemporary machines, all the more so if they choose 12 bit instead of just 8. Thankfully so, because the old analog boat anchors can't be ordered anymore anyway. Instead of this, analog engineers benefit from the massive increased capabilities, like automated measurements, advanced math including a properly implemented FFT and bode plot applications, which can replace a signal analyzer in quite a few cases.

(1) EDIT: Well, there is a way to disable the SPO engine ... by selecting "slow acquisition" in the Acquire menu. Maybe that's what happened here.
Title: Re: Help me choosing new Oscilloscope
Post by: smallfreak on April 11, 2023, 10:05:53 am
Thanks for all those interesting links. I will try to keep up with this information and try not to look like a complete noob next time.  ::)
Time to get my new scope soon and get hands on experience. Obviously this all can be done "right", but sometimes people just do not care about the wave looking "jaggy" on the DSO screen.
Title: Re: Help me choosing new Oscilloscope
Post by: Wallace Gasiewicz on April 11, 2023, 08:04:10 pm
I cannot resist    QUOTE:
Slow sample rates, short memories, the attempt, to overcome this
Are you talking about scopes or my current mentation? Seems quite accurate both ways..
Title: Re: Help me choosing new Oscilloscope
Post by: Performa01 on April 12, 2023, 10:10:07 am
Thanks for all those interesting links. I will try to keep up with this information and try not to look like a complete noob next time.  ::)
Time to get my new scope soon and get hands on experience. Obviously this all can be done "right", but sometimes people just do not care about the wave looking "jaggy" on the DSO screen.
I forgot to provide you with the most relevant link though:

https://www.eevblog.com/forum/testgear/sds2000x-plus-bandwidth-aliasing-application-note/ (https://www.eevblog.com/forum/testgear/sds2000x-plus-bandwidth-aliasing-application-note/)

This is a detailed discussion about bandwidth and sample rate - and how they both impact signal representation and -fidelity, based on facts and practical demonstrations using appropriate gear.


I cannot resist    QUOTE:
Slow sample rates, short memories, the attempt, to overcome this
Are you talking about scopes or my current mentation? Seems quite accurate both ways..

Me too! ... we don't exactly get younger, do we?  ;) :-DD
Title: Re: Help me choosing new Oscilloscope
Post by: smallfreak on April 14, 2023, 03:51:51 pm
I forgot to provide you with the most relevant link though:
https://www.eevblog.com/forum/testgear/sds2000x-plus-bandwidth-aliasing-application-note/ (https://www.eevblog.com/forum/testgear/sds2000x-plus-bandwidth-aliasing-application-note/)

This is a detailed discussion about bandwidth and sample rate - and how they both impact signal representation and -fidelity, based on facts and practical demonstrations using appropriate gear.

Ah, really! It took a while to find the hidden gem (attachment) that is part of your entry post. Very interesting indeed. I saved it in my library.

I could have saved a lot of time reading, if I had found this earlier. All questions answered.  :-+

Thanks again - fellow countryman.  :D
Title: Re: Help me choosing new Oscilloscope
Post by: smallfreak on April 17, 2023, 02:46:04 pm
SDS2104X-Plus including "Promo Pack" Finally ordered. Hope it will arrive soon.

If anyone is curious, "Batter Fly" (Italy) still has a few Siglent Promo Kits available "while supply lasts".
https://www.batterfly.com/shop/de/siglent-sds2104x-plus (https://www.batterfly.com/shop/de/siglent-sds2104x-plus)

I think, this is still by far the best deal to get the SDS2104X-Plus together with the SPL2016 Probe here, especially if you know that the price billed for the scope is not the shown 1199€ (+VAT) but still the promo price of 959,00€ (+ VAT) as listed on their "Promotions" page. That makes the entire bundle 50 bucks cheaper than the bare scope without any options (compared to siglent.eu or Amazon) so you get the SPL2016 essentially for free.


Ah, no, I'm not getting bonus for this advertizing. I'm just happy to save the insurance company some 500€  :palm:
Title: Re: Help me choosing new Oscilloscope
Post by: vpjustme on April 29, 2023, 04:11:21 pm
Thank you verz much. I have just ordered this with the free promotion (free bandwith upgrade).
Title: Re: Help me choosing new Oscilloscope
Post by: Martin72 on May 01, 2023, 12:44:39 am
SDS2104X-Plus including "Promo Pack" Finally ordered. Hope it will arrive soon.

Congrats to the currently best scope(in summary) in this price segment.
Serious meant.
I had it for two years until the HD was launched, at work we have six of them everyday in "pro" use.