Alf P. Steinbach wrote: > * Steve Holden: >> Alf P. Steinbach wrote: >>> * Lie Ryan: >>>> On 01/15/10 05:42, Alf P. Steinbach wrote: >>>>> I'm beginning to believe that you maybe didn't grok that simple >>>>> procedure. >>>>> >>>>> It's very very very trivial, so maybe you were looking for something >>>>> more intricate -- they used to say, in the old days, "hold on, this >>>>> proof goes by so fast you may not notice it!" >>>> Since you said it's trivial, then... >>> You can't get it more trivial. >>> >>> >>>>>> Nothing about you there. Just the information you are promoting. I >>>>>> don't >>>>>> normally deal in innuendo and personal attacks. Though I do >>>>>> occasionally >>>>>> get irritated by what I perceive to be hogwash. People who know me >>>>>> will >>>>>> tell you, if I am wrong I will happily admit it. >>>>> There's a difference between an algorithm that you can implement, and >>>>> hogwash. >>>> please prove your claim by writing that algorithm in code and post >>>> it in >>>> this list. The program must accept a .wav file (or sound format of your >>>> choice) and process it according to your algorithm and the output >>>> another .wav file (or sound format of your choice) that sounds roughly >>>> similar to the input file. >>> First, the (very very trivial) algorithm I posted does *not* do that: by >>> itself it represents a sine wave, not an arbitrary wave form. >>> >>> And second I'm not about to write Fourier transform code to satisfy >>> someone who refuses to do a milligram of thinking. >>> >>> The Fourier part stuff needed to do what you're requesting is >>> non-trivial, or at least it's some work to write the code. >>> >>> >>>> PS: I have near-zero experience with sound processing >>>> PPS: I will be equally delighted seeing either Steve admitting his >>>> wrong >>>> or you admit your hogwash >>>> PPPS: An alternative way to convince us is to provide a paper/article >>>> that describes this algorithm. >>>> PPPPS: Though I will be quite sad if you choose to reject the challenge >>> I don't believe any of what you write here. >>> >> Well, it seems quite reasonable to me, but then I'm not the one being >> challenged to write a trivial algorithm. > > You're again into innuendo, misleading statements and so forth. Lie > Ryan's challenge is nothing but trivial, because it's about implementing > very much more than the algorithm. I did implement the algorithm for > him, in Python, and posted that in this thread. > > >> I will, however, observe that your definition of a square wave is what I >> would have to call a "'square' wave" (and would prefer to call a "pulse >> train"), as I envisage a square wave as a waveform having a 50% duty >> cycle, as in >> >> ___ ___ >> | | | | >> | | | | >> | | | | >> +---+---+---+---+ and so on ad infinitum, (though I might allow you >> | | | | to adjust the position >> | | | | of y=0 if you want) >> |___| |___| >> >> as opposed to your >> >> _ >> | | >> | | >> ______| |______ ______ >> | | >> | | >> |_| >> > > Try to read again, a sufficient number of times, how to generate the > latter by summing *two instances of the former*. > > I'm sorry to say this but I find it hard to explain things simple enough > for you, because at the level of 2+2 any explanation is far more complex > than the concept itself. > > That is, of course, a challenge to me! :-) > > So, thanks for challenging my pedagogical abilities. > > I know they're not as good as they should be, and need some exercise! > > >> So I can see how we might be at cross purposes. I could cite authorities >> for differentiating between a square wave and a symmetric pulse train, >> but will content myself with observing only that my impression is the >> common definition of an ideal square wave (one with a zero transition >> time) admits of only two instantaneous values, eschewing the zero you >> use. If that is the case, we could perhaps agree that we differ merely >> on terminology. > > No, we don't differ on terminology: we seem to differ in that one of us > has severe difficulties understanding the very simplest things, such as > what graph one gets by summing two squares waves of same frequency but > out of phase. > > The one of us who has trouble understanding that is also apparently too > lazy to try out the earlier advice given him of graphing this on a piece > of paper, and instead prefers to spout innuendu, personal attacks and > misleading statements. > > That's a real challenge to the other person. > > >> Or, best of all, you could show me how to synthesize any waveform by >> adding square waves with a 50% duty cycle. Then I *will* be impressed. > > You would, yes? > > Perhaps you'd also admit to being wrong, and retract your innuoendo etc.? > > Well, just epress the waveform as a sum of sine waves (Fourier > transform); synthesize each sine wave by a set of 50% duty cycle square > waves (I've earlier posted Python code for that in this thread); add all > the square waves. The hard part of this is implementing the Fourier > transform, I leave that to you. ;-) > Finally, I think, the penny is beginning to drop. Give me a little more time to think about it and I can see I might be willing to write the words "I was wring". Shame about my typing, isn't it? ;-)
regards Steve -- Steve Holden +1 571 484 6266 +1 800 494 3119 PyCon is coming! Atlanta, Feb 2010 http://us.pycon.org/ Holden Web LLC http://www.holdenweb.com/ UPCOMING EVENTS: http://holdenweb.eventbrite.com/ -- http://mail.python.org/mailman/listinfo/python-list
