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| Siglent SDS1104X-E vs. Rigol DS1054Z Advice? |
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| rf-loop:
--- Quote from: Fungus on August 28, 2018, 07:56:31 am --- The only thing 'suspicious' about those measurements was subtracting 3dB from the Siglent's noise level just because you felt like it. --- End quote --- Still it looks like you do not understand that there in image was two oscilloscopes with as same situation and settings as can. These can compare. No need look measurements results as all. And Siglent measurement level can see in image. There is not any 3dB subtraction. Onlöy what I tell was that BW difference is 1:2 and you know (or then you do not know) where from this 3dB come. Also I have knowledge and experience well enough for claim around 3dB noise level rise when turn Siglent 100MHz to 200MHz BW. Not of course exatly due to fact that there is also some noise components what are not related to analog side BW. 3dB tip was only from common 10 Log(200 /100) If we compare Rigol and Siglent then take 100MHz Rigol and 100MHz Siglent and then Siglent show even less noise. If you do not believe it is your own problem. Here compared same Siglent scope with 100MHz BW and 200MHz 100MHz out from box This new test have same settings so they are quite highly comparable and also same individual scope. Same individual scope mod to 200MHz As can see theory and practice is as same as it can be. (because there is also other things related to noise) If we look how much it rise and take randomly example CH4. Level (Vrms 1) rise 3.14dB And if we look how our BW shape and BW width change, it can say that it is just as expected. 1. V Stdev = V rms - possible DC offset Different scopes are difficult to compare if look noise p-p because then we need collect same amount of data for measurement and sorry but it looks like with Rigol effective amount of measured data points are really low compared to Siglent due to slower wfm/s in faster times and with slow time bases highly decimated data points. With random gaussian distribute noise this is very important. Probability for catch highest p-p values with Rigol is really low if compare Siglent. If we compare random noise p-p we need collect and analyze same amount of measured data. Example here previously as you told Rigol use 1200 points for measurements. And in this image prevciously where was Rigol and Siglent this Siglent use 7M points. If with this setting turn p-p measure on ... well Rigol tell p-p from random noise using 5800 times less data. Of course propbability to find rare highes peaks rise lot of. This is why we need compare apples to apples and not apple to shoe. |
| Fungus:
--- Quote from: rf-loop on August 28, 2018, 09:00:27 am ---Onlöy what I tell was that BW difference is 1:2 and you know (or then you do not know) where from this 3dB come. --- End quote --- I know where it came from, I'm just saying that it shouldn't be "compensated" or reduced in any way because of $THEORY$. The noise you see on screen is going to be there every time you look at a signal, even if a different brand of oscilloscope has less bandwidth than yours(!) |
| Fungus:
FWIW the displayed RMS value will halve (approximately) if you zoom in on the Rigol. This halved value is a more correct representation of the noise. I have two problems with the comparison above, they are: a) Not knowing (or wilfully misrepresenting) how Rigols work, and b) "Compensating" the Siglent down by 3dB (because, hey, why not?) Don't get me wrong: I believe the Siglent probably has a lower noise than the Rigol (but then it ought to, it costs more). I'm just questioning the data being presented here and trying to point out that trying to measure it is almost impossible. If you watch Dave's video I posted above you can clearly see he's not willing to make a definitive statement because it depends on a lot of variables. PS: The Rigol makes no claims to having a 500uV range. A more realistic comparison would be the visible noise with them both on their lowest range, ie. Siglent on 500uV and the Rigol on 1mV. That's the noise that people interested in those ranges are actually going to see (in real life!) whenever they look at a signal. Define your requirements: If you need 500uV then buy a Siglent (or better... eg. a 10 bit R&S). I know we're all volt-heads around here but for most people/jobs, 1mV of noise (eg. Rigol) isn't a problem. |
| KungFuJosh:
--- Quote from: Fungus on August 28, 2018, 08:58:58 am ---Rigol will soon have their new ASIC in a low-end model, so... meh. --- End quote --- Do you have any specifics about this? Hopefully they have a new design for the front panel too. I think both companies are in a funny position. Only Rigol's highest-end scopes are relatively new (from what I could see), and they still don't have a good front panel design. I hate the arbitrary, asymmetrical goofy outlines. Looks better than Instek, but that's a low bar. It also seems like only the SDS1004X-E series is relatively new from Siglent, and everything higher-end is trailing behind. I like the look, larger screens, and individual vertical controls of some of the higher-end Siglent models. But why would I spend 4 times as much money for less scope ability than 1104X-E? Yes, I know there's higher bandwidth and sampling available, but the rest of the scope needs to catch up. |
| Fungus:
--- Quote from: KungFuJosh on August 28, 2018, 12:42:53 pm --- --- Quote from: Fungus on August 28, 2018, 08:58:58 am ---Rigol will soon have their new ASIC in a low-end model, so... meh. --- End quote --- Do you have any specifics about this? --- End quote --- Obviously not. No company leaks information like that. (not until a few weeks before launch). --- Quote from: KungFuJosh on August 28, 2018, 12:42:53 pm ---Hopefully they have a new design for the front panel too. I hate the arbitrary, asymmetrical goofy outlines. Looks better than Instek, but that's a low bar. --- End quote --- Meh. You probably wouldn't notice it after a day of use. --- Quote from: KungFuJosh on August 28, 2018, 12:42:53 pm ---It also seems like only the SDS1004X-E series is relatively new from Siglent, and everything higher-end is trailing behind. I like the look, larger screens, and individual vertical controls of some of the higher-end Siglent models. But why would I spend 4 times as much money for less scope ability than 1104X-E? Yes, I know there's higher bandwidth and sampling available, but the rest of the scope needs to catch up. --- End quote --- Siglent has been investing in the low-range (to compete with the DS1054Z, which has made Rigol a ton of money) while Rigol has been investing in the the mid-range. The situation should flip around now the respective new models have been launched. Let's see if Rigol startes dropping some hints a few weeks from now. (to make anybody who's thinking of going from DS1000Z to SDS1000X-E wait a while before deciding :popcorn: ) |
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