What is "time resolution"?
Reply #130 – 2006-11-19 17:25:30
Euclid? If you want to have a scientific discussion perhaps following the standard of scientific publications would be a good idea. Either put up a proof or a reference to a published document containing a proof. I roughly recall Euclid doing some early explorations into the 'geometry of space" You guys need references to remind you that "phase" and "delay" exist in different dimensions? perhaps compare "phase space" with "space time"It looks like we're going in circles. a bit like phase space -infinite cycles SebastianG :"I see you, ChiGung, posted some Java code that estimates the positions of peaks (quite badly I might add" - Its just an approximation to get the ball running. Like i said im interested if you might describe a better method. We could also see how the methods compare. When ive tidied the code up a bit,it will be quite easy to modify.SebastianG :"but since the signal you used is oversampled at least 4 times it doesn't hurt that much). But what was the point of doing it? You didn't have to "prove" that bandlimitation changes something. Nobody questioned it." - Ive had to respond to a great deal of dismissals and missreports, but here are some quotes about youre claim that "nobody questioned it" :If you are saying that, in PCM, distortion is introduced by the impulse response of the system, then please demonstrate that this distortion is even plausibly audible. Note the sly attempt to shift context from detectability to "audibility"Resolution refers about the smallest time event that can be resolved. KikeG never questioned its existence, just dismissed its relevance. I am attempting resolve events and observe their timing differences throughout different bandwidths/samplerates, to inform claims about pcm time resolution. @SebastianG - you might have a better appreciation of my efforts if you were more familiar with the content of this thread:Chigung wrote: "Detail of any time localisable events, will be distorted by the implicit lowpass of conversion by an unknowable amount (post conversion) by upto a sample-period-width of difference."This is completely incorrect. Please do not state it as a fact, and please do not reproduce this myth where it may confuse others. (not just "incorrect" but completely incorrect - followed by an order to desist saying so(!) Do people read HA to learn? How well is sense defended here?So, we have two filters. If _both_ filters block everything above fs/2, then the sampling stage itself will be transparent - lossless, if you like. In other words, these two systems would be identical... I have never disagreed with this, but this is the fact which has been repeatedly put forward to show the futility of examining timing differences between different samplerates/bandwidths of the same potential source. Because it only considers sources with the same bandwidth - it is an irrelevant, disruptive case -especialy when repeated often throughout this thread as something i 'dont get'SebastianG :"Why should we accept your definition of time resolution? Is there any practical reason for it? Who cares about how peaks may move on arbritrary signals due to band limitation?" - 'Arbitrary' is a dismissive term to use there, this an investigation of practical time resolution in pcm of various kinds of source including music tracks. Who cares? The thread is "what is time resolution", this is the R&D section of an audio forum. But hey it might be true,that no one but me really cares about the subject.SebastianG :"Lemme say that I think I know what situation you are in. I wouldn't be honest if I denied that I've never been in a similar situation (me being sure about something and thinking everybody was wrong). Hopefully one realizes what's going on and feels only a little embarressed -- instead of really ashamed because of name calling, arrogant behaviour or whatever..." - Sincerely thanks, but i dont think you have appreciated the thrust of this debate, or how my ultimately trivial situation in this thread might relate to my circumstances outside of it. I am self critical and acknowledge my faults, i percieve that you all too should perform some critical introspection.ChiGung :"btw, i confirmed that the spike in the preceeding plots is a bug, .... maybe if you didnt save time, and built your own codebase, you just might realise that "phase shift and time delay" are different...." One wonders how you can make these two statements and keep a straight face. They arent related. If you develope your understanding from first principals you are more likely to spot fundamental differences between different entities like "phase shift" and "time delay" - than if you prematurely seek the meanings of the terms as reported by other peoples studies.Garf : "If you are going to try arguing based on the implication that results from Octave would somehow be flawed, compared to your own software, then I think there is absolutely no point in continuing this argument further." - Ive no idea why you suspect that. Please do present comparable results from Octave if you get the time. --- Im not over the moon, that my program is not working completely yet, but it will when I get an hour or so to concentrate on fixing it. Its not complex compared to my other projects, just a quick throwing together of a couple of parts. I could just await more accurate data on the matter from you guys and your own tools, but suspect that might never materialise. If i dont bother finishing the program, who has contributed less? Me, or those who simply refered the great job their own favourite tools could do? chigung : "maybe if you didnt save time, and built your own codebase, you just might realise that "phase shift and time delay" are different...." I see you're resorting to insuts again. I didnt mean for that to be insulting to you. Please examine your own manners of expression. (I attempt to fairly return the respect i recieve)chigung:Phase shift's 'dimension' is tightly cyclic, No, it's not. 2 pi is not the same phase shift as 4 pi, although sometimes measuring which is which requires good understanding, or in some cases even the use of time delay to disambiguate between 2 pi and 4 pi. This reported subtlety does not make phase shifts dimension equivalent to realtime's. However you arrange it, you cant show these things are equal. But you do often half report a theoretical contention, before handwaving towards further neccessary 'studies' Woodinville :"I would suggest, again, that you go back and learn the basic definitions for what you seek." - I gather if i suggested that to you, you would report insult. -- 'fair regards to you all, cg