Products > Test Equipment
Oscilloscope recommendation DS1054Z / SDS1104X-E / GDS-1104B / etc?
mawyatt:
--- Quote from: nctnico on June 20, 2023, 08:23:18 am ---
--- Quote from: mawyatt on June 19, 2023, 02:53:15 pm ---We've used the Siglent Bode function often, and have also reported it's slow, real slow (we are not a fanboy)!! With this in mind it does give superb results as mentioned by 2N3055, slow yes, but accurate with a very wide dynamic range if utilized properly by someone that understands how the Bode function operates within the DSO.
If getting the correct, accurate answers is important, one can often overlook the speed!!
--- End quote ---
Now you make it sound like slow = accurate but that simply isn't true. The results from R&S's implementation (the one I have experience with but I don't see why others should be different) are just as accurate. So they deliver the same answer in less time. I have repeated several of the measurements you have shown using my R&S oscilloscope and got to the same results.
--- End quote ---
No, no not saying that slow always equals accurate. Just saying that within a given measurement/equipment scenario that if one needs specific accurate results, often slow is acceptable. Suspect the R&S is faster and also accurate, we don't have one so can't say for sure, we don't comment on equipment we don't have and put very little faith in comments by others that don't have said equipment in hand.
Would like to see how well the R&S behaves with the Peltz Oscillator Injection Locking experiment mentioned (wish we had one to compare), would expect good results tho as from what we've gathered from various reviews, and the informative videos and responses by R&S Engineer pdenisowski, R&S MSO features seem well done.
Best,
mawyatt:
--- Quote from: 2N3055 on June 20, 2023, 11:11:32 am ---
There is also one more thing that were discussing. It is much easier to measure filters (passive and active) in quiet environment, than loop response of switching PSU with aggressor signals being orders or magnitude larger.
With switching PSU, ability of BODE plotter (whatever it is) to extract phase/gain of stimulus is very much a question of extracting very small signal from switcher natural output ripple.
In which case frequency selective detector and averagning helps a lot.. In which case slower is better....
So yeah, it is MUCH more complicated than: SLOW!!!! BAD!!!!!
--- End quote ---
Agree, this is a condition that really stresses the measurement with a high interfering signal hiding the wanted low level signal, kinda like what a radio receiver must deal with!! The Injection Locking experiment placed the interfering signal (oscillator output) quite close to the tiny wanted Bode signal, and thus our comments :-+
Best,
Fungus:
--- Quote from: nctnico on June 19, 2023, 12:02:08 pm ---It is actually rather interesting that none of the Siglent fan crowd has ever commented on the slowness of Siglent's FRA. Either they didn't want to tell or just don't know any better. Rudi's comparison where it comes to the time needed to do a sweep came as a total -shocking- surprise to me!
--- End quote ---
Oh, now you've done it ... you said something bad about a Siglent! :scared: :scared: :scared: :scared: :scared: :scared:
mawyatt:
--- Quote from: Fungus on June 20, 2023, 03:38:18 pm ---
--- Quote from: nctnico on June 19, 2023, 12:02:08 pm ---It is actually rather interesting that none of the Siglent fan crowd has ever commented on the slowness of Siglent's FRA. Either they didn't want to tell or just don't know any better. Rudi's comparison where it comes to the time needed to do a sweep came as a total -shocking- surprise to me!
--- End quote ---
Oh, now you've done it ... you said something bad about a Siglent! :scared: :scared: :scared: :scared: :scared: :scared:
--- End quote ---
Everyone that's actually used the Siglent Bode or FRA function, whatever you want to call it, has said it's slow; ourselves, 2N3055, Rudi, and so on. This is likely a consequence of the massive amount of computational energy required to do such, and puts a serious strain on the available computational resources (likely why everything else slows down or stops completely when Bode is active). We must remember that all the Siglent Bode effects are created purely in the digital domain (read software) without any hardware participation nor acceleration (to the best of our knowledge). The R&S may have higher computational resources available, may have hardware assist, or maybe just a better method to implement the function, will let the folks that actually have and know this fine instrument comment tho.
The real discussion as pointed to by 2N3055 is "at this price point" nobody has a competing instrument period!!
We challenge you or anyone to show this isn't true, and if someone finds a better solution then we all benefit :-+
We'll repeat again what we've said all along, the Siglent Bode implementation is technically a superb effort, and at this price point a great value added feature. Recall some actually stating that the Siglent Bode function was just a toy feature, obviously they were/are uninformed!!
All this discussion begs the evaluation of the higher end Siglent instruments for Bode speed. We call all these instruments (DSO & MSO) because they are really highly sophisticated, high speed/resolution, data acquisitions systems with excellent low noise and high dynamic range analog front ends with wonderful digital display renderings :)
Anyway, maybe someone with various instruments (1000, 2000, 5000 & 6000 series) at hand could do a comparison of Bode Function speed? Would be interesting to see if the newer Siglent instruments are significantly faster than the entry and mid level devices. This might hint at where the bottleneck is regarding speed.
Best,
mawyatt:
We find it somewhat amusing that the very mention of a "scope" of any form, brings up the usual heated discussions and arguments when the reality is that the "scope" offerings by the major sources discussed are actually all superb instruments, and far more that just a visual rendering of a time domain waveform.
They all are so darn good, we should be thankful and admiring the engineering genius behind them rather than trying to nitpick them apart :palm:
Best,
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