Author Topic: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review  (Read 3727 times)

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Offline Performa01

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #25 on: June 16, 2019, 10:08:19 am »
Still, honestly, some aspects of this review have been undermining my enthusiasm for the DS5000X quite a bit. It's also kinda shocking to hear in the 21st century that enabling sin(x)/x interpolation causes a major drop in acquisition (or waveform update) rate and that the specified values are only for dot mode. What about linear interpolation?
There is no difference. it quite obviously is the additional display points that slow the acquisition rate down, no matter what's the math behind it.
Measurements with an old pre-release firmware (won't be much different today) show that at 20ns/div the trigger rate is 110k with single channel and 100k with both channels in dot mode. It is 23k4 for single channel and 2k8 for dual channel in vector mode.
That sounds bad, but then again we can use dots mode in most situations, because it looks nearly the same on the screen and avoids all the shortcomings of interpolation:
- no graphics processing overhead
- no unstable waveform display in the presence of strong aliasing products
- better intensity grading

Since the interpolation is just a post processing, we can switch it on anytime after the acquisition, e.g. in the history.

Anyway, in direct comparison to the RTM3K directly next to it, I like the (Lecroy-ish) control panel and matte screen of the SDS5000X much better but there's no way denying that everything on the RTM3K looks just sleeker and more polished. E.g. the FFT implementation on the Siglent just looks underwhelming compared to the one on the RTM3K (despite using much less points).
Yes, it is traditional Math FFT right now. Next FW release includes configurable peak and harmonic search with list view as well as configurable FFT length:


SDS5104X_FFT_Peaks_02_Avg10

A spectrum analyzer package is on the todo list, which should provide a simple and easy setup, similar to a real SA.
 
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Online nctnico

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #26 on: June 16, 2019, 10:40:22 am »
It seems to be a jack of all trades, but a master of none.

Plus lots of annoying bugs you don't usually find with the major brands. Looks like a rush job and another re-run of the Rigol MSO7000 :(
I don't agree with this. From what I gathered from this forum Siglent is much better at getting a working product onto the market compared to Rigol nowadays (as Dave also notes in his review). Rigol still seems to compete on price where Siglent seems to understand that to enter the professional market succesfully the first priority is a good product and price comes second.

I do agree with 0xdeadbeef. The RTM3004 is way more polished. The next step Siglent needs to take is to look at improving productivity. For starters: let the user select the memory depth. On the SDS2000 (I had the misfortune to own) the automatic (short) memory depth setting was a major nuisance. I never ever ever want to use an oscilloscope which doesn't have a user selectable/fixed memory setting.
« Last Edit: June 16, 2019, 10:46:37 am by nctnico »
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Offline 0xdeadbeef

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #27 on: June 16, 2019, 11:54:53 am »
I never ever ever want to use an oscilloscope which doesn't have a user selectable/fixed memory setting.
I'm with you there in principle. But (AFAIK) even e.g. the LeCroy 6Zi I use at work doesn't allow to set a fixed a sample memory size. It allows to set a fixed sample rate though. This allows me to determine if I either prefer a faster update (lower sample rate) or keep the possibility to zoom into details (faster sample rate). This goes so far that if the memory is not sufficient to capture the full screen with the given sample rate, only a part of the screen is updated. This flexibility is missing in all the Agilent/Keysight scopes that I used so far (but I haven't used too many models there).

So I'm concerned that the SDS5000X doesn't seem to allow to set either a fixed memory size nor a fixed sample rate. There's just this "slow" and "fast" acquisition mode which is not really explained in the manual.
Side note: I had a look in the RTM3K user manual and it seems as if there is only a "maximum" record length configurable as well. So it looks like there's neither a fixed memory length nor a fixed sample rate possible. I could be wrong though.
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Online nctnico

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #28 on: June 16, 2019, 01:56:41 pm »
I never ever ever want to use an oscilloscope which doesn't have a user selectable/fixed memory setting.
I'm with you there in principle. But (AFAIK) even e.g. the LeCroy 6Zi I use at work doesn't allow to set a fixed a sample memory size. It allows to set a fixed sample rate though. This allows me to determine if I either prefer a faster update (lower sample rate) or keep the possibility to zoom into details (faster sample rate). This goes so far that if the memory is not sufficient to capture the full screen with the given sample rate, only a part of the screen is updated. This flexibility is missing in all the Agilent/Keysight scopes that I used so far (but I haven't used too many models there).

So I'm concerned that the SDS5000X doesn't seem to allow to set either a fixed memory size nor a fixed sample rate. There's just this "slow" and "fast" acquisition mode which is not really explained in the manual.
Side note: I had a look in the RTM3K user manual and it seems as if there is only a "maximum" record length configurable as well. So it looks like there's neither a fixed memory length nor a fixed sample rate possible. I could be wrong though.
In the RTM3K you can select several memory depths from a few kpts (IIRC) to 80Mpts so you can set a trade-off between memory length, samplerate and update rate. Keysight always uses the maximum memory depth on their Megazoom based scopes.
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Offline 0xdeadbeef

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #29 on: June 16, 2019, 02:51:17 pm »
In the RTM3K you can select several memory depths from a few kpts (IIRC) to 80Mpts so you can set a trade-off between memory length, samplerate and update rate.
Hm, OK, I wasn't sure about that, but good to hear.

Keysight always uses the maximum memory depth on their Megazoom based scopes.
I'm not totally convinced that this is totally true in every scenario. Problem here is that the detail behavior is very important. There are scopes which only really sample the full buffer (including the data that doesn't fit on the screen) in single trigger mode and scopes which do that also in normal mode. There are scopes that perform automatic measurements only from the sample buffer and scopes that perform these measurement from intermediate buffers (screen buffer or specialized measurement buffers). At least from my limited experience with 7000 series Agilent and DSOX3000 Keysight scopes I would think that Agilent/Keysight scopes are optimized for fast update rate and short dead times and therefore perform some trickery there.

BTW: Automatic measurements are one reason why defining a fixed sample rate can be more desirable than defining a fixed memory width as the sample rate directly defined the measurement resolution. Scopes that choose the sample rate automatically to optimize the update rate are somewhat problematic regarding resolution of measurements.
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Online 2N3055

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #30 on: June 16, 2019, 03:56:32 pm »
Keysight 3000T doesn't always use whole memory.

From fastest timebase 500ps/div to 20us/div it samples in such way that if you sample at 500ps/div and stop, you can "zoom out" to 20us/div.
So if you running from anywhere from 500ps/div to 20 us/div and  stop it from run, you get 1 MPoints of data after trigger (minus pre trigger time).
In single mode you get to expand out to 50 us/div, which gives 2,5 Mpoints of data.

If you are running slower timebase than 20us/div in RUN and 50us/div in single, you get only data that you see on the screen, plus minus 150us before and after so 650us altogether, at 2.5GS/s, which gives 1,625 MPoints.  In SINGLE mode all the same, except 5GS/s which gives 3,25 MPoints.

And it changes as you go through timebases. 
So I would say that Keysight has a strategy to maximize memory used when you go to STOP or SINGLE mode. But memory length is nor fixed nor maximum all the time.

And in a run mode it is not running full memory but some sort of circular buffer, and uses only one frame worth of data, to maximize waveforms per second rate..
When you stop it, it reassembles all the buffers in one full capture.
It is actually quite clever, but not very simple to understand.

Other strategy is one that is used by LeCroy, Picoscope and some others, that you can set  MAX sample size, but it will fetch exactly and only length of data that you set it to. So for instance 50us/div, at 10 div horizontal, will result in 500us of data being captured. Not a point more or less. And also it will try to sample with as quick sample rate as it will try to maximize sample points to achieve max set size. Meaning if you set for 10MPoints MAX, at 1GS/s, you will get 1MPoints in a capture that is 1ms long.  In capture 1us long (100ns/div, 10div) you will get only 1000 points.  Because it is ruled by capturing exact time interval. Max sample size will be in effect only when time base is slow enough that with highest sample rate it would want to acquire 2 Gpoints of data. So, you decide how much is too much, and then it starts slowing down sample rate..

It's really two schools of thought, optimized for different usage patterns. I think both are useful. What bothers me is that scope could be made to be able to do both but nobody does it..
 

Online nctnico

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #31 on: June 16, 2019, 04:44:15 pm »
Keysight 3000T doesn't always use whole memory.

From fastest timebase 500ps/div to 20us/div it samples in such way that if you sample at 500ps/div and stop, you can "zoom out" to 20us/div.
So if you running from anywhere from 500ps/div to 20 us/div and  stop it from run, you get 1 MPoints of data after trigger (minus pre trigger time).
In single mode you get to expand out to 50 us/div, which gives 2,5 Mpoints of data.

If you are running slower timebase than 20us/div in RUN and 50us/div in single, you get only data that you see on the screen, plus minus 150us before and after so 650us altogether, at 2.5GS/s, which gives 1,625 MPoints.  In SINGLE mode all the same, except 5GS/s which gives 3,25 MPoints.
But this isn't due to speed but due to double buffering and memory sharing. In normal mode the memory is divided between an acquisition and display buffer so you effectively get half the memory depth. There are other factors at play as well like reference traces and digital input memory which also eat away from the available memory. In short: on a Keysight Megazoom scope it is tricky to get use of the full memory depth. It is not a feature but a limitation.
« Last Edit: June 16, 2019, 04:46:08 pm by nctnico »
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Offline David Hess

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #32 on: June 17, 2019, 12:35:25 am »
Dave, the tests I would like to see include:

1. RMS noise measurement of a calibrated source - many DSOs do not do this correctly.  This should be done at different sample rates and with and without aliasing.  The result should be invariant.

2. Transient response - this could require verification of your signal source on a trusted oscilloscope.

3. Trigger after delay - to see if it even exists.  Many DSOs do not support this and in some cases the documentation is deceptive.
 

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #33 on: June 17, 2019, 12:54:46 am »
I never ever ever want to use an oscilloscope which doesn't have a user selectable/fixed memory setting.

The Keysight X series doesn't let you select memory depth and I've never found it a problem in practice.
 

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #34 on: June 17, 2019, 01:08:15 am »
Dave, thanks for the review  :-+

But I've got to place some small criticism here -- your input noise comparison is somewhat dodgy (34:00 into the video): Since the R&S had some visible DC offset of the input signal (round about -300µV), this will clearly contribute to the RMS measurement. Try checking noise with the inputs in AC coupled mode. Depending on the internal processing, the average offset will get subtraced in this mode (not sure if it works this way on the R&S, at least the "mature" Rigol products do it like this).
Then I'm sure you'll find that the R&S is at least on par with the new Siglent scope.

AC coupling makes no difference.
But you are right, the DC offset matters.
Just powered it up again and it happened to have almost no DC offset and a I got 107uV RMS, and it's 87uV in standard deviation mode.
After a bit the offset rose and the standard deviation gets rid of it, still around 87uV
 

Offline TheSteve

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #35 on: June 17, 2019, 06:20:06 am »
I never ever ever want to use an oscilloscope which doesn't have a user selectable/fixed memory setting.

The Keysight X series doesn't let you select memory depth and I've never found it a problem in practice.

The newest 3000t firmware does now let you select memory depth and as a result also lets you see the current memory it is using. I don't know when you'd want to lower the memory but it is nice seeing how much it is actually using.
VE7FM
 

Offline Smokey

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #36 on: June 17, 2019, 06:59:12 am »
Say you are a company that has a long reputation for making inexpensive buggy questionably specced stuff, but you want to get into the higher end market with a new expensive product and sell it internationally to compete with major players.  At what point do you just change your name or spin off another company with a new name under which to sell the higher end stuff and drop the baggage of all the previous toy products? 
 

Online nctnico

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #37 on: June 17, 2019, 08:39:56 am »
I never ever ever want to use an oscilloscope which doesn't have a user selectable/fixed memory setting.

The Keysight X series doesn't let you select memory depth and I've never found it a problem in practice.
That is because you always get the maximum depth (which isn't much to begin with) on a Keysight and Keysight uses some trickery to make the update rate independent of the memory depth. But the way Siglent does it (only sample enough to fill the screen) is really annoying; you have to change the time/div setting all the time.
« Last Edit: June 17, 2019, 08:52:44 am by nctnico »
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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #38 on: June 17, 2019, 10:17:47 am »
The newest 3000t firmware does now let you select memory depth and as a result also lets you see the current memory it is using. I don't know when you'd want to lower the memory but it is nice seeing how much it is actually using.

Ah, didn't know that, will have to update. Yes, it's always handy to know.
 

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #39 on: June 17, 2019, 10:19:26 am »
Say you are a company that has a long reputation for making inexpensive buggy questionably specced stuff, but you want to get into the higher end market with a new expensive product and sell it internationally to compete with major players.  At what point do you just change your name or spin off another company with a new name under which to sell the higher end stuff and drop the baggage of all the previous toy products?

Isn't that when you sell it with a Lecroy badge?  ;D
 

Offline thm_w

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #40 on: June 17, 2019, 08:04:45 pm »
Intensity grading, i don't give a shit. I prefer "temperature" color grading a million times over DPO style intensity grading

Incidentally, none of the scope i have and use at work (picoscope, tek TPS, SDS-5035X, lecroy 7200A -the one from the 80s-) have intensity grading, at most they have color grading and in the rare times i need such a thing i prefer it over starndard intensity grading, but that's me

Sure,  but something is odd with how they are calculating/displaying it. Almost as if the number of gradients is too low or something.
But this could have been due to another setting Dave had on at the time (mem depth, etc.).
 

Offline Performa01

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #41 on: June 17, 2019, 08:38:33 pm »
Sure,  but something is odd with how they are calculating/displaying it. Almost as if the number of gradients is too low or something.
But this could have been due to another setting Dave had on at the time (mem depth, etc.).
No, it wasn't Dave's fault. I tried to reproduce it and was quite baffled to find the SPO engine broken (didn't notice it before, as I've mostly tested other features like new measurements, FFT and Bode Plot lately).

So the SPO issue has been confirmed and Siglent R&D is working on a fix.

I for one do value an intensity grading that is actually working all the time, independent of memory and other settings, because it provides additional information about the signal, just like analog scopes did. It makes the difference between a true color display and a pen plotter ;)

Even though I use (and like) Picoscopes a lot, I don't see any value in special modes that provide intensity and color grading exclusively together with high waveform update rates, but a lot of limitations otherwise. It's quite obviously the USB bottleneck that forced Picotech to copycat Tek in this regard.

Siglent also has a special mode, called Sequence Recording, but only for waveform cature rates up to 500kWfm/s and no  limitations other than screen update rate, whereas intensitiy grading has to work all the time without the need for a special mode.


On this occasion I'd like to clarify another misconception in the video: the [Roll] button is there to enable or disable Auto-Roll mode. I for one don't like auto-roll at all, but for those who want it, it is still available, no problem.
 
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Offline rf-loop

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #42 on: June 18, 2019, 10:21:16 am »
Since the interpolation is just a post processing, we can switch it on anytime after the acquisition, e.g. in the history.

 :-+

This is one of very good thing in all Siglent X series oscilloscopes - even when it slows wfm/s. (wfm/s is many times bit overvalued salesmen advertising value). In all cases there is true sample points available in runtime and afterwards and it draw Sinc perfectly via true sample points (No violation of rule.)
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Offline Smokey

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #43 on: June 18, 2019, 11:55:02 am »
Say you are a company that has a long reputation for making inexpensive buggy questionably specced stuff, but you want to get into the higher end market with a new expensive product and sell it internationally to compete with major players.  At what point do you just change your name or spin off another company with a new name under which to sell the higher end stuff and drop the baggage of all the previous toy products?

Isn't that when you sell it with a Lecroy badge?  ;D

Ya, but if you think you are ready to go at it alone on your own name it might help to have a name that isn't immediately (and not unfairly) associated with software bugs and questionable quality. 
Also it's not like when people find out their Lecroy Wave-whatever was made by Siglent that they feel better about it.
 

Offline JPortici

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #44 on: June 18, 2019, 12:33:08 pm »
And yet, to be fair, hardware quality has always been increasing in scopes, SA, power supply, signal generator, ..
Software quality is also constantly increasing. The 5000X is a very good example. While there are still bugs and more advanced features are not yet implemented the user interface is already beyond anything they had done before and if we put aside what i think are quirks (encoder acceleration, traces don't move as smoothly as i would like, some menus are missing in the firmware release he used, some touch actions that i would take from granted are missing in the firmware release he used) it is actually very good and what i would expect from any mid range product. Lecroy style. The effort in making a good quality product there.
Then i don't know if you have used the newer spectrum analyzer series but the user interface is very good there as well and i would consider the firmware to be in a mature state.

but i don't expect everyone to see it, we all have different expectations in how an instrument should operate, and whenever it doesn't it's easy to blame it on the manufacturer

if i "found out" that my lecroy is actually a siglent i wouldn't feel good because i would wonder WHY i spent double the money, and that's it. Altough i don't know yet if the rebadge of the 5000x will be actually done and if it will use lecroy's os (like the WS3K) or the siglent firmware, but with lecroy's logo
 

Offline 0xdeadbeef

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #45 on: June 18, 2019, 04:51:50 pm »
This is one of very good thing in all Siglent X series oscilloscopes - even when it slows wfm/s. (wfm/s is many times bit overvalued salesmen advertising value). In all cases there is true sample points available in runtime and afterwards and it draw Sinc perfectly via true sample points (No violation of rule.)
Maybe I didn't get the point but I can't imagine that any scope on the market isn't interpolating the displayed waveform from "true" sample points. At least in single shot mode there simply isn't any choice, or is it? And in the "digital phospor" / intensity grading modes. I would assume the samples of previous acquisition are not really existing anymore, just the previous waveform(s) must be stored somewhere to process the grading.
Anyway, I still find it puzzling that any kind of interpolation divides the acquisition rate by a factor of four (or more).

if i "found out" that my lecroy is actually a siglent i wouldn't feel good because i would wonder WHY i spent double the money, and that's it. Altough i don't know yet if the rebadge of the 5000x will be actually done and if it will use lecroy's os (like the WS3K) or the siglent firmware, but with lecroy's logo
At least currently, rebranded entry level scopes are white, while "real" LeCroys with ProBus are black (wasn't always like this though). The WS3000(Z) is obviously considered a "real" LeCroy even though it's the result of a cooperation with Siglent. Since the WS3000(Z) doen't have the bandwidth limitation for the lower ranges, I would think that things like the frontend are (at least partly) designed by LeCroy. Anyway, as long as the WS3000Z (aka SDS3000X) marks the entry point for black LeCroy scopes, it doesn't make much sense to rebrand the SDS5000X which is superior to the WS3000Z at least in some aspects (e.g. memory depth).
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Offline JPortici

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #46 on: June 18, 2019, 07:33:47 pm »
AFAIK the WS3000 is all siglent built on specifications given by lecroy, the only lecroy IP is the software. The reason why the new frontend is limited for the 1GHz model (is not in my scope, which is the 350MHz model) was explained somewhere by Performa01 (i don't remember which thread exactly)

the 5000X is superior in many aspects: more memory, more grunt, better screen.
Lacks the integrated AWG, which in the lecroy is stupidly limited for which i prefer
- No generator
- Control of external generator from the scope
- External brick (forget the SAG1021.. there's going to be the SAG1021I where "I" stands for isolated, +/-42V of isolation according to http://www.saelig.com/supplier/siglent/sds5000x-datasheet-0519-saelig.pdf)

The firmware from lecroy is of course more flexible as in multiple math channels, more advanced math on math, more advanced math.

But I have used both and there is no comparison. It would make way more sense to drop the WS3000 and replace it with the 5000X
« Last Edit: June 18, 2019, 07:36:26 pm by JPortici »
 

Online nctnico

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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #47 on: June 18, 2019, 07:36:40 pm »
This is one of very good thing in all Siglent X series oscilloscopes - even when it slows wfm/s. (wfm/s is many times bit overvalued salesmen advertising value). In all cases there is true sample points available in runtime and afterwards and it draw Sinc perfectly via true sample points (No violation of rule.)
Maybe I didn't get the point but I can't imagine that any scope on the market isn't interpolating the displayed waveform from "true" sample points.
The Rigol DS1054Z seems to be the only exception. But otherwise the sample points are including in sin x/x reconstruction by definition. All in all rf-loops statements makes it look like Siglent is more special then what it is in reality.
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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #48 on: June 18, 2019, 08:53:23 pm »
This is one of very good thing in all Siglent X series oscilloscopes - even when it slows wfm/s. (wfm/s is many times bit overvalued salesmen advertising value). In all cases there is true sample points available in runtime and afterwards and it draw Sinc perfectly via true sample points (No violation of rule.)
Maybe I didn't get the point but I can't imagine that any scope on the market isn't interpolating the displayed waveform from "true" sample points.
The Rigol DS1054Z seems to be the only exception. But otherwise the sample points are including in sin x/x reconstruction by definition. All in all rf-loops statements makes it look like Siglent is more special then what it is in reality.
I wouldn't be so sure..........
.............
I have both and there is something I don't really like in the DS1000Z series: when you select "dots" mode it doesn't display actual samples, but interpolated data which, in my opinion, is a big mistake. Rigol developers seem to favor some cosmetic criteria when deciding how to display data (non transparent handling of sin(x)/x interpolation, no real dots mode, etc).
..................
...............
6. In Dots mode you don’t see dots; even at small time base (2 ns) dots are connected with lines.
[FW v00.01.01.04.04] / [FW v00.01.01.04.04]
..................
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Re: EEVblog #1220 - Siglent SDS5000X 1GHz Oscilloscope Review
« Reply #49 on: June 18, 2019, 09:03:39 pm »
@tautech: As I wrote in my previous post: so far the Rigol DS1054Z seems to be the only exception. Pehaps you should include the oscilloscope model  WinnieThePooh is testing (the Rigol MSO5000 series) and the problem he describes in you short (likely out of context quote) has nothing to do with sin x/x reconstruction. Don't make the same mistake rf-loop made in his eagerness to make things prettier than they are or make standard features look special. It sounds like a clueless salesperson; 'Look, this Siglent calculator is showing 2 when I punch in 1+1'. Real engineers will be put off by those kind of tactics.
« Last Edit: June 18, 2019, 09:05:25 pm by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 


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