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| First picture on EEVblog of the new R&S MXO4 series oscilloscope :) |
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| Wolfgang:
... In reality, there are never 18Bits. What counts is the effective number of bits, and a measurement of this reveals that the effective bits are below 11, regardless of what they claim. Look here: https://electronicprojectsforfun.wordpress.com/to-enob-or-not-to-enob/ The other manufacturers (and also R&S for their better scopes) give ENOB values in their specs. For the MXO, there are none (for a good reason). |
| maxwell3e10:
--- Quote from: Wolfgang on August 12, 2023, 11:27:48 pm ---... In reality, there are never 18Bits. What counts is the effective number of bits, and a measurement of this reveals that the effective bits are below 11, regardless of what they claim. Look here: https://electronicprojectsforfun.wordpress.com/to-enob-or-not-to-enob/ The other manufacturers (and also R&S for their better scopes) give ENOB values in their specs. For the MXO, there are none (for a good reason). --- End quote --- Thanks for an amazing level of analysis! I think it's interesting to compare the spectra of the scopes directly. Picking only one largest peak obscures how "clean" the spectrum is and the level of white noise. In many cases having a second or third harmonic due to a non-linearity is not so bad. Also high resolution is often useful to see small features at the end of a large signal (like tail end of a decay) in a single shot. So SNR and DR can be useful characteristics in addition to SINAD and can also be converted to an ENOB, where "effective" has a different meaning. |
| Martin72:
--- Quote from: Wolfgang ---The other manufacturers (and also R&S for their better scopes) give ENOB values in their specs. --- End quote --- Right, Siglent for example, but also (and of course) Lecroy, even Rigol.... For the HDO4000, for example, it was afaik 8.5 bits (without further details). Lecroy specifies between 8.4 and 8.7, depending on the bandwidth of the model (WS 4000HD), Siglent also. And Siglent are the only ones who write which parameters they used for this: --- Quote ---1:99.99 MHz input(100 MHz model uses 49.99 MHz),-0.5 dBFS,20 mV/div,50 Ω input impedance --- End quote --- I assume that lecroy measures similarly. And nobody knows how Rigol measured it. ;) I would like to repeat your measurements on my siglent, but unfortunately I don't have the equipment(only a SDG2122X). But you described a self-built oscillator for this purpose, is there any more information about it? Gladly in a separate thread, otherwise this will be too offtopic here. |
| Wolfgang:
--- Quote from: Martin72 on August 13, 2023, 10:40:28 am --- --- Quote from: Wolfgang ---The other manufacturers (and also R&S for their better scopes) give ENOB values in their specs. --- End quote --- Right, Siglent for example, but also (and of course) Lecroy, even Rigol.... For the HDO4000, for example, it was afaik 8.5 bits (without further details). Lecroy specifies between 8.4 and 8.7, depending on the bandwidth of the model (WS 4000HD), Siglent also. And Siglent are the only ones who write which parameters they used for this: --- Quote ---1:99.99 MHz input(100 MHz model uses 49.99 MHz),-0.5 dBFS,20 mV/div,50 Ω input impedance --- End quote --- I assume that lecroy measures similarly. And nobody knows how Rigol measured it. ;) I would like to repeat your measurements on my siglent, but unfortunately I don't have the equipment(only a SDG2122X). But you described a self-built oscillator for this purpose, is there any more information about it? Gladly in a separate thread, otherwise this will be too offtopic here. --- End quote --- Hi Martin, the ENOB test oscillator schematics is at the bottom of the ENOB page. regards Wolfgang |
| Wolfgang:
--- Quote from: maxwell3e10 on August 13, 2023, 03:39:05 am --- --- Quote from: Wolfgang on August 12, 2023, 11:27:48 pm ---... In reality, there are never 18Bits. What counts is the effective number of bits, and a measurement of this reveals that the effective bits are below 11, regardless of what they claim. Look here: https://electronicprojectsforfun.wordpress.com/to-enob-or-not-to-enob/ The other manufacturers (and also R&S for their better scopes) give ENOB values in their specs. For the MXO, there are none (for a good reason). --- End quote --- Thanks for an amazing level of analysis! I think it's interesting to compare the spectra of the scopes directly. Picking only one largest peak obscures how "clean" the spectrum is and the level of white noise. In many cases having a second or third harmonic due to a non-linearity is not so bad. Also high resolution is often useful to see small features at the end of a large signal (like tail end of a decay) in a single shot. So SNR and DR can be useful characteristics in addition to SINAD and can also be converted to an ENOB, where "effective" has a different meaning. --- End quote --- Hi, I think different. A discerned "spike" in the spectrum corresponds to a perceivable "wiggle" in the time domain, and that, IMHO, hurts more than just a randomly increased noise level, as it can be mistaken for a "real" signal. It all depends on what kinds of signal you are working with. regards Wolfgang |
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