Products > Test Equipment

Functional comparison of R&S RTB2000, Siglent SDS2000X and Keysight DSOX1000

<< < (21/39) > >>

rf-loop:
Just tested it with one other Siglent scope model (not just SDS2000X Plus because I do not have it now). ETA 2022-04-16: yes it was unpublished SDS2000 HD what I can tell now after Performa01 have published it.
what have around same memory, samplerate and royghly same wfm speed specs.
Only for show that different settings give different result.
Also looked how dots/vectors x/Sinc  affect in this case and no notable changes.
This is NOT comparable directly with SDS2000X Plus!! So for it this is nonsense but only show that different setup give different result.

Same signal and only to CH1  and same trig. CH2, 3 and 4 just only on without signal.
All memory lengths same as displayed wfm length (display width 2ms (200us/div))
10k memory, 5MSa/s  ~317 acquistion/s (wfm/s)
100k memory 50MSa/s ~319 acquistion/s (wfm/s)
1M memory 500MSa/s ~245 acquistion/s (wfm/s)
2M memory 1GSa/s ~179 acquistion/s (wfm/s)

Same signal and only to CH1  and CH4 just on without signal,  same trig.
20k memory, 10MSa/s  ~319 acquistion/s (wfm/s)
200k memory 100MSa/s ~313 acquistion/s (wfm/s)
2M memory 1GSa/s ~179 acquistion/s (wfm/s)
4M memory 2GSa/s ~91 acquistion/s (wfm/s)

Same signal and only to CH1,  same trig.
20k memory, 10MSa/s  ~326 acquistion/s (wfm/s)
200k memory 100MSa/s ~326 acquistion/s (wfm/s)
2M memory 1GSa/s ~179 acquistion/s (wfm/s)
4M memory 2GSa/s ~91 acquistion/s (wfm/s)
All these "memory" lengths mean true current acquisition lenght (not max memory length set value - if it differ)
And this length is same as displayed signal lenght.

Measured trig out using HP 53131A HS010 using 1s Gate time. Peak values are, or may be, slightly higher.

And now I repeat again.
Please, @RBBVNL9,  can you tell what was different scopes current true acquisition lengths (samples) and sampling speed. (in your image)

RBBVNL9:
In reponse to 2N3055 and rf-loop:


--- Quote ---Please can you clarify every oscilloscope sampling speed and current acquisition true memory length used in this image.
--- End quote ---

--- Quote ---Could you check something on Siglent? If you go into Acquistion  menu, do you have Slow or Fast mode set there? You need to be in the dot mode also..
--- End quote ---

Below are the settings that were used for the measurement reported earlier (in the PicoScope screen print): 

RTB:
-   Record length: 10 kSa. Note: at 200kSa I start to see a slight reduction in trigger events per second. At 10Msa there are roughly half the number of trigger events per second.
-   Sample rate is 4.81 MSa/s (this number changes when other record lengths are selected)
-   Trigger output pulse set to 1ms using TRIGger:OUT:PLENgth 1E-3
-   Only Channel 1 activated.

SDS
-   Record length (parameter “MAX record length”) setting is 20k. Interestingly, any other setting (200k, 2M, 20M, 200M) does not make any difference for this measurement
-   Sample rate is 10.0 MSa/s (this number changes when other record lengths are selected)
-   “Acqu Mode” set to “Fast”. Interestingly, changing it to “Slow” does not make any difference for this measurement
-   “Seq. Acq. Switch” set to off. When it is turned on, I see sets of n acquisitions (where n is the number set by the “Seq Segment” parameter” with almost 100mS 100ms in between, so a considerable drop in the number of trigger events per second.
-   Display Type = Vectors. But setting it to dots makes no difference whatsoever.
-   Only Channel 1 activated.

DSOX
-   Sample rate is 500MSa/s. ASAIK this rate is simply a function of the chosen timebase setting, there is no other way to choose this.
-   Segmented memory is off (but when turned on, that has no impact on the number of trigger out pulses)
-   Only Channel 1 activated.


Those are the kind of relevant parameters, I guess. But perhaps there are others that matter? 

rf-loop:

--- Quote from: RBBVNL9 on April 05, 2022, 09:43:22 am ---In reponse to 2N3055 and rf-loop:


--- Quote ---Please can you clarify every oscilloscope sampling speed and current acquisition true memory length used in this image.
--- End quote ---

--- Quote ---Could you check something on Siglent? If you go into Acquistion  menu, do you have Slow or Fast mode set there? You need to be in the dot mode also..
--- End quote ---

Below are the settings that were used for the measurement reported earlier (in the PicoScope screen print): 

RTB:
-   Record length: 10 kSa. Note: at 200kSa I start to see a slight reduction in trigger events per second. At 10Msa there are roughly half the number of trigger events per second.
-   Sample rate is 4.81 MSa/s (this number changes when other record lengths are selected)
-   Trigger output pulse set to 1ms using TRIGger:OUT:PLENgth 1E-3

SDS
-   Record length (parameter “MAX record length”) setting is 20k. Interestingly, any other setting (200k, 2M, 20M, 200M) does not make any difference for this measurement
-   Sample rate is 10.0 MSa/s (this number changes when other record lengths are selected)
-   “Acqu Mode” set to “Fast”. Interestingly, changing it to “Slow” does not make any difference for this measurement
-   “Seq. Acq. Switch” set to off. When it is turned on, I see sets of n acquisitions (where n is the number set by the “Seq Segment” parameter” with almost 100mS in between, so a considerable drop in the number of trigger events per second.
-   Display Type = Vectors. But setting it to dots makes no difference whatsoever.

DSOX
-   Sample rate is 500MSa/s. ASAIK this rate is simply a function of the chosen timebase setting, there is no other way to choose this.
-   Segmented memory is off (but when turned on, that has no impact on the number of trigger out pulses)

--- End quote ---

DSOX have 1us and SDS have 2us max trig interval in segment & sequence mode.


--- Quote ---SDS
-   “Seq. Acq. Switch” set to off. When it is turned on, I see sets of n acquisitions (where n is the number set by the “Seq Segment” parameter” with almost 100mS in between, so a considerable drop in the number of trigger events per second.
--- End quote ---

This is really weird. Even If I test with this same signal with SDS1104X-E and 200us/div and Sequence. I take oneshot sequence with 50MSa/s 140k length and  when I look segments   time stamps they have all 3ms (3000us) delta time. So 333.33  segments in second.
Then I change it to 14k memory so 5MSa/s and look 1900 segment single sequence. Every single segment in sequence time stamp delta time is 3ms. So 333.33...  segment/s
Then with 1GSa/s 2.8M current mem lenght (one segment length)...  still all 19 segments delta time is 3ms.... 333.33... segment/s

What is this your 100ms or  (or mS as you said, aka milli Siemens what is conductance SI derived unit)

In SDS2000X Plus is some severe bug in Sequence mode or some external reason... ;)

Someone:

--- Quote from: 2N3055 on April 05, 2022, 08:39:35 am ---They also mention casually memory sizes, but 3000T has only 500k of sample memory when doing 4ch+ digital normal mode (4 buffer-2 per ch-1 with digital -0.5  Mpts for ping pong buffers. 1Mpts for Single mode). Scope with 100Mpts will be 100x slower everything else being equal. Scope with 500MPts will have soo much more work to do.
--- End quote ---
You can keep pulling up the same "small memory" argument, except it is common for memory to change in different acquisition settings across most scopes. Those characteristics are not avoided in the Keysight data sheets or left as only up-to/maximum/peak values, and made very clear in the manuals (contrasting to these other examples discussed here where it is not clear at all what is expected).

But you make the false claim that there is a comparison with memory depth, the waveform capture measurements that competitors use keep the memory depth very short to inflate their numbers. Look at how much slower the competitors are despite choosing less memory! (when at same memory they are far behind). Scopes are not some computer system where the parts are put together in imbalanced ways by the end user, they are a finished product from the manufacturer who has decided on the system performance. Keysight make a real time scope with 100Mpts of memory, the EXR or MXR series, without a significant drop in waveform rate (keeping the system balanced).

Where you keep falling over is trying to make out like all scopes work/function the same. The Keysight megazoom method has been to decouple display and waveform memory, they are two different paths that dont interact. Acquisition data is piped to the display plotter/memory (through decimation etc) separately to the waveform memory. As you say before, to make things fast they chose to put most of the emphasis/features on the decimated view (positive example: fast eye diagrams). Most other scopes draw the waveforms from the acquisition memory, and take measurements from the original data (Lecroy being the extreme example of that, positive example: higher resolution measurements). Completely different with advantages and disadvantages, for comparisons they are best listed as characteristics rather than put as a good/bad binary check box against specific/your preference.

Someone:

--- Quote from: rf-loop on April 05, 2022, 10:22:12 am ---
--- Quote from: RBBVNL9 on April 05, 2022, 09:43:22 am ---SDS
-   “Seq. Acq. Switch” set to off. When it is turned on, I see sets of n acquisitions (where n is the number set by the “Seq Segment” parameter” with almost 100mS in between, so a considerable drop in the number of trigger events per second.
--- End quote ---

This is really weird. Even If I test with this same signal with SDS1104X-E and 200us/div and Sequence. I take oneshot sequence with 50MSa/s 140k length and  when I look segments   time stamps they have all 3ms (3000us) delta time. So 333.33  segments in second.
Then I change it to 14k memory so 5MSa/s and look 1900 segment single sequence. Every single segment in sequence time stamp delta time is 3ms. So 333.33...  segment/s
Then with 1GSa/s 2.8M current mem lenght (one segment length)...  still all 19 segments delta time is 3ms.... 333.33... segment/s
--- End quote ---
I think the explanation is good, with the sequence mode in run mode:
[n sequences without gaps] 100ms processing interval [n sequences without gaps] 100ms processing interval... etc

Interesting it was not in a circular mode (does not support it?) where the sequences capture around forever until stop is pressed.

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod