jabbr Posted April 14, 2018 Share Posted April 14, 2018 2 hours ago, pkane2001 said: Whats the difference between phase noise and jitter? In many cases none. Particularly uncorrelated jitter. Correlated jitter Is where the signal on one line leaks onto another line (a clear signal integrity issue) Phase noise has a clear mathematical definition and when appropriate, I prefer that term. Custom room treatments for headphone users. Link to comment
jabbr Posted April 14, 2018 Share Posted April 14, 2018 8 hours ago, PeterSt said: @jabbr, I am sure this makes sense to you, but not to me. It is high time that you describe your meaning of "isolated". Try to avoid the figurative speak now, because that doesn't help in understanding. It may also point you at not legitimate recursiveness (see, I can do it too ). I gave a common language an SQ based definition. I will offer an electrical definition. Isolation means that the outout of the DAC does not depend on the signal integrity of the inputs to the DAC. Given inputs that are bitwise identical, but not necessarily electrically identical, the output of the DAC will not vary. (In this definition isolation means complete isolation. partial isolation will approach this to the extent that it approaches completeness) This is a definition — we can now discuss how to electrically measure the DAC output and which measurements should be considered valid Custom room treatments for headphone users. Link to comment
jabbr Posted April 14, 2018 Share Posted April 14, 2018 8 hours ago, PeterSt said: Yes, your definition. So your definition needs adjustment because it doesn't work out. Stop the theories. First fire up XXHighEnd, drag in your NOS1a/G3 DAC, leave out the measurement gear this time and listen. Nothing could be more easy. All it requires is doing it. You know, there's so much theorizing around in CA. Every body knows best. But this time you won't get away with it because it is too easy to test it yourself. Perfect show case. I am not theorizing! Ive provided a common language definition — if you disagree then provide your own — provide a simple language definition so we can talk about the same thing!!! Now could I test phase error, yes, but that is an entirely different question. Custom room treatments for headphone users. Link to comment
Summit Posted April 14, 2018 Share Posted April 14, 2018 58 minutes ago, pkane2001 said: Phase noise or jitter are not measurements, they are the actual variation in timing of digital samples, which can be measured in frequency domain or in time domain. Regardless of how you measure them, they represent the same physical effect. Yes phase noise and jitter are different ways of measuring (quantifying) the same phenomenon. But remember that you there the one that asked “Whats the difference between phase noise and jitter? And I simply answered the question, which is that phase noise is measurements of variations in signal timing presented in the frequency domain and jitter is measurements of the variations in the time domain. The very difference IS which parameters of the signal that has been measured no way around it! https://www.eetimes.com/document.asp?doc_id=1277196 Link to comment
pkane2001 Posted April 14, 2018 Share Posted April 14, 2018 Just now, Summit said: Yes phase noise and jitter are different ways of measuring (quantifying) the same phenomenon. But remember that you there the one that asked “Whats the difference between phase noise and jitter? And I simply answered the question, which is that phase noise is measurements of variations in signal timing presented in the frequency domain and jitter is measurements of the variations in the time domain. The very difference IS which parameters of the signal that has been measured no way around it! You missed the context of my question, which was an answer to another statement. -Paul DeltaWave, DISTORT, Earful, PKHarmonic, new: Multitone Analyzer Link to comment
Summit Posted April 14, 2018 Share Posted April 14, 2018 1 minute ago, pkane2001 said: You missed the context of my question, which was an answer to another statement. No matter the context the very difference IS still which parameters of the signal that has been measured no way around it! Link to comment
jabbr Posted April 14, 2018 Share Posted April 14, 2018 8 hours ago, PeterSt said: @jabbr, So you have two inputs on your NOS1a/G3. The one is the USB isolated input (denoted "i") the other is without (but still has the internal i2s isolation) (denoted "u"). Try XXHighEnd and the SFS of our thread's subject and vary the input. Don't forget to use your Lush vs the stock cable (which is also good). If you after this stil dare to participate with the same stipulations as you try to do so far, then ... No, you won't. So no need to work this out further. BUT It would be very useful, regarding your knowledge by now on the phase error measurements. Again I am serious ... Yes I could do this but haven’t for several reasons: 1) my NOS1a/G3 is for my own enjoyment and as an example of a terrific ladder based DAC. As I’ve told you I have a stack of the good PCM1704 chips that a long time ago was going to use to build a PCM DAC but that project has gotten pushed so so far down the stack of projects that I relented and got the NOS1a/G3! It’s terrific. 2) I have a longstanding interest in what I consider a new SDM DAC topology as well as proper isolation for such and my own equipment is for this development. I don’t want to reverse engineer anything you’ve done 3) I’m 6 months behind in some of my own day job work (not my primary work which is only a month behind!) to the point where I’m returning checks etc. 4) I’d love to bring some things into commercial production but wrestle with the ROI. New projects come up with very promising/real ROI and as you know this keeps purely interesting projects on the back burner ? 5) I’m usually browsing/writing on my iPhone — in between meetings, or while sonething is cooking, and it can be really hard to get through a meandering thread Custom room treatments for headphone users. Link to comment
PeterSt Posted April 14, 2018 Share Posted April 14, 2018 22 minutes ago, jabbr said: I will offer an electrical definition. Isolation means that the outout of the DAC does not depend on the signal integrity of the inputs to the DAC. To me that is (again) a functional description. Lush^3-e Lush^2 Blaxius^2.5 Ethernet^3 HDMI^2 XLR^2 XXHighEnd (developer) Phasure NOS1 24/768 Async USB DAC (manufacturer) Phasure Mach III Audio PC with Linear PSU (manufacturer) Orelino & Orelo MKII Speakers (designer/supplier) Link to comment
pkane2001 Posted April 14, 2018 Share Posted April 14, 2018 1 minute ago, Summit said: No matter the context the very difference IS still which parameters of the signal that has been measured no way around it! Again, no. The context was not measurement but the cause of audible differences. In that context, phase noise and jitter are the same physical effect and it makes no sense to distinguish them. -Paul DeltaWave, DISTORT, Earful, PKHarmonic, new: Multitone Analyzer Link to comment
PeterSt Posted April 14, 2018 Share Posted April 14, 2018 18 minutes ago, jabbr said: I am not theorizing! [...] Now could I test phase error, yes, but that is an entirely different question. It is exactly not, because it is the opposite of theorizing. Theorizing : providing theories instead of practices. It is not an entirely different question because it is about that. What to do with you theories while you can also provide practice. Not unimportant side note : I can not provide the practice (on phase noise). So ? Lush^3-e Lush^2 Blaxius^2.5 Ethernet^3 HDMI^2 XLR^2 XXHighEnd (developer) Phasure NOS1 24/768 Async USB DAC (manufacturer) Phasure Mach III Audio PC with Linear PSU (manufacturer) Orelino & Orelo MKII Speakers (designer/supplier) Link to comment
Summit Posted April 14, 2018 Share Posted April 14, 2018 10 minutes ago, pkane2001 said: Again, no. The context was not measurement but the cause of audible differences. In that context, phase noise and jitter are the same physical effect and it makes no sense to distinguish them. OMG! You asked “Whats the difference between phase noise and jitter? I answer that. You then try to lecture me about thing you know nothing about. Link to comment
pkane2001 Posted April 14, 2018 Share Posted April 14, 2018 Just now, Summit said: OMG! You asked “Whats the difference between phase noise and jitter? I answer that. You then try to lecture me about thing you know nothing about. Maybe you should go back to defining the word ‘is’. That was much more helpful. -Paul DeltaWave, DISTORT, Earful, PKHarmonic, new: Multitone Analyzer Link to comment
PeterSt Posted April 14, 2018 Share Posted April 14, 2018 14 minutes ago, jabbr said: Yes I could do this but haven’t for several reasons: Jonathan, no excuses are required for anything. It is your life and you do what you enjoy best. It is only that it seems odd (comes across like that) that you clearly like to join the discussion, end up in disagreement (OK, to some small extent) while all is under your own control, actually (you have more relevant gear than e.g. I have). That is all. No further discussion needed. 17 minutes ago, jabbr said: 4) I’d love to bring some things into commercial production but wrestle with the ROI. New projects come up with very promising/real ROI and as you know this keeps purely interesting projects on the back burner ? Yes. I should know and understand. And we can't split ourselves. I will shut up now towards you. Lush^3-e Lush^2 Blaxius^2.5 Ethernet^3 HDMI^2 XLR^2 XXHighEnd (developer) Phasure NOS1 24/768 Async USB DAC (manufacturer) Phasure Mach III Audio PC with Linear PSU (manufacturer) Orelino & Orelo MKII Speakers (designer/supplier) Link to comment
Summit Posted April 14, 2018 Share Posted April 14, 2018 5 minutes ago, pkane2001 said: Maybe you should go back to defining the word ‘is’. That was much more helpful. No need for that, most people already know what the word is mean. The difference between phase noise and jitter, on the other hand…. Link to comment
PeterSt Posted April 14, 2018 Share Posted April 14, 2018 Okay, when I see "all of you" write about phase noise vs. jitter, then all I think is : Phase noise ? what is that ? Is it noise that disturbs the phase ? The phase ? hmm ... the phase angle ? the phase angle ? hmm ... something with frequency ? I don't think phase noise as such exists. It is not about noise as per the terms we think about electrical noise. It is about "disturbance" (which probably can be expressed as noise in mean square root etc. voltage). Phase Error, as in the measurement of what the phase angle should be for the given frequency and how much it deviates, would be the thing it is about. And with that, Phase Error as such would be a frequency thing, while jitter is a time thing. But still not correct because we sure don't need an FFT for Phase Error as such (while an FFT can be used to see jitter) and thus is Phase Error just about the (deviated) angle of the wave cycle (at any of 4 slopes of choice) at a given (two) point(s) on it. I could go further by (my own) defining that Phase Error is related to one wave cycle (actually 1/4th of it) and how any start of it relates to the end of it and how these mathematically must match for phase angle (take two even points and the angle must be the same but opposite in direction). If not, there's a certain amount of jitter, which causes the squeeze or stretch. All made up by me and without formulas which I wouldn't be able to cough up to begin with. Now go look what WikiPedia says ... I didn't (yet). Lush^3-e Lush^2 Blaxius^2.5 Ethernet^3 HDMI^2 XLR^2 XXHighEnd (developer) Phasure NOS1 24/768 Async USB DAC (manufacturer) Phasure Mach III Audio PC with Linear PSU (manufacturer) Orelino & Orelo MKII Speakers (designer/supplier) Link to comment
Popular Post jabbr Posted April 14, 2018 Popular Post Share Posted April 14, 2018 Briefly : consider a pure sine wave : it has a frequency, phase, amplitude. The amplitude can be expressed as voltage & current each of which can have noise. The voltage & current noise each have their own pattern. Assume frequency constant for the moment. Likewise phase can have noise ie variation of phase over time. In the same way that voltage noise can be described as an error or deviation from the ideal sine wave, so can the phase error be described as a variation from the constant. Summit and semente 2 Custom room treatments for headphone users. Link to comment
Popular Post Summit Posted April 14, 2018 Popular Post Share Posted April 14, 2018 https://www.eetimes.com/document.asp?doc_id=1277196 jabbr and semente 2 Link to comment
jabbr Posted April 14, 2018 Share Posted April 14, 2018 Taking the voltage error (noise) over time firms it’s own signal which can be analyzed by FFT. The phase error (noise) similarly. By varying the phase, this causes a change in the signal frequency! The pure 1khz sine wave, is now represented as a collection of sine waves. Given a pure tone input (1khz) and in the presence of phase noise, the result is a plot of dB-V vs frequency offset So 1khz +|- 0.001 hz +|- 1hz etc Custom room treatments for headphone users. Link to comment
jabbr Posted April 14, 2018 Share Posted April 14, 2018 This: http://www.crystek.com/crystal/spec-sheets/clock/CCHD-575.pdf Custom room treatments for headphone users. Link to comment
jabbr Posted April 14, 2018 Share Posted April 14, 2018 56 minutes ago, PeterSt said: To me that is (again) a functional description. Yes of course functional. It that a problem? Those are my favorite kinds of definitions ? Custom room treatments for headphone users. Link to comment
semente Posted April 14, 2018 Share Posted April 14, 2018 1 hour ago, pkane2001 said: You missed the context of my question, which was an answer to another statement. It wasn't an answer but a question. It didn't clarify, correct, elucidate, educate... "Science draws the wave, poetry fills it with water" Teixeira de Pascoaes HQPlayer Desktop / Mac mini → Intona 7054 → RME ADI-2 DAC FS (DSD256) Link to comment
jabbr Posted April 14, 2018 Share Posted April 14, 2018 Note that when reading phase error plots, the X axis is not frequency but frequency offset/error from the carrier. Also this relationship between phase error/offset and frequency error/offset has been well known for a very long time! https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720004506.pdf Custom room treatments for headphone users. Link to comment
jabbr Posted April 14, 2018 Share Posted April 14, 2018 Cost effective phase error measurement: https://www.by-rutgers.nl/PDFiles/DC-receiver.pdf http://hpmemoryproject.org/news/3048/hp3048_01.htm You too can do SOA phase measurement for much less $$ than you expect ? Custom room treatments for headphone users. Link to comment
pkane2001 Posted April 14, 2018 Share Posted April 14, 2018 1 hour ago, semente said: It wasn't an answer but a question. It didn't clarify, correct, elucidate, educate... Wow, tough crowd today it was a leading question. I’m now sorry I asked. -Paul DeltaWave, DISTORT, Earful, PKHarmonic, new: Multitone Analyzer Link to comment
semente Posted April 14, 2018 Share Posted April 14, 2018 25 minutes ago, pkane2001 said: Wow, tough crowd today it was a leading question. I’m now sorry I asked. Not at all. You just asked the wrong person, me. I just needed clarification. I'm somewhat ignorant in these matters... "Science draws the wave, poetry fills it with water" Teixeira de Pascoaes HQPlayer Desktop / Mac mini → Intona 7054 → RME ADI-2 DAC FS (DSD256) Link to comment
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