On Tue, 07 Sep 2004 09:07:15 +0200, Bernhard Holzmayer <holzmayer.bernhard@deadspam.com> wrote: (snipped)> >Sorry for the delayed question >(holidays on the lake of Constance (Germany) were splendid!),(snipped)> >BernhardHello Bernhard, ah, you are breaking my heart! Lake Constance, ... I'd give almost anything to sit with my feet in the lake, look at the surrounding hills, and drink a local German pilsner beer! If there is no Lake Constance and no German pilsner beer in heaven, then I don't want to go to heaven. [-Rick-]
Window functions
Started by ●August 31, 2004
Reply by ●September 7, 20042004-09-07
Reply by ●September 8, 20042004-09-08
Jerry Avins wrote:> Bernhard Holzmayer wrote: > >> Jerry Avins wrote: >> >> >>>Stan Pawlukiewicz wrote: >>> >>> >>>>Jon Harris wrote: >>> >>> ... >>> >>> >>>>>That may be true, but the windowing technique can be very >>>>>useful when you need >>>>>to calculate filter coefficients "on the fly". >>>>>Computationally, it is much >>>>>simpler than the optimized methods. So while it might be >>>>>sub-optimal, I wouldn't say it is obsolete. >>>>> >>>>> >>>> >>>>Signal Processing with flies should be called FSP ;) >>> >>>The dyslexics among us sometimes store data in flies. >>> >>>Jerry >> >> >> Sorry for the delayed question >> (holidays on the lake of Constance (Germany) were splendid!), >> but the food chain of curiosity seems to be closed-loop: >> I still want to know what OY! in the topic means! >> >> Is it another stroke of applied dyslexics, and should read OT >> instead, or is it just a personalized form which has to do with >> the last letter of JerrY ? >> >> Bernhard > > It started as a typo; T and Y are adjacent keys. Then I laughed at > the shortening of "Oy Weh!"Great. That's really something that had swept through my mind, though I don't speak Yiddish. Ten years ago, I'd been in Isreal on a guided tour. In an old synagogue, a very old (around eighty, I guess) man told us all the story of the synagogue - around 20..30 min. In the beginning I didn't understand anything. But the longer I listened to the man, the more familiar I got with the tune. After a while, I really started to get hold of the meaning of what he was saying. Only with my understanding of German (and maybe some other languages like English...). Was really amazing.> (spelled "oy, vay" in Yiddish > transliteration to English) and decided to leave it. I apologize > for the distraction. > > Jerry
Reply by ●September 8, 20042004-09-08
[posted and emailed] Rune, your original article expired off this server, but I just came across something in my files that may be of interest to you. In your original article http://groups.google.com/groups?selm=f56893ae.0408310548.8ba60b4%40posting.google.com you wrote:>I'm playing a bit with window functions in filter design etc, and >have come across a couple of gruelling expressions. More specifically, >the Chebychev window [1, eq. 5-17], the Tukey window [2, table 8.1] >and the Lanczos window, [2, table 8.1]. > >I would like to know how one estimates the width of the main lobe >for these filters, and how one uses the various control parameters. >Table 8.1 in P&M seems to contain quite a few typos, which does not >exactly help me understand what's going on.The classic, seminal paper on Window functions, written with comprehensive reference tables and illustrative plots, is Frederic J. Harris, "On the Use of Windows for Harmonic Analysis with the Discrete Fourier Transform," Proceedings of the IEEE, Vol 66, No. 1, January 1978. (This is the same Harris of the Blackman-Harris window function.) Windows are known by several names, and I don't see Chebychev or Lanczos in that paper, but they may be known as something else (there's a Dolph-Chebychev, which may be what you mean). The Tukey is also known as a cosine-taper window, and a triangle window is also known as a Fejer or Bartlett, for example. For all the window functions, he has this table of "figures of merit" showing highest sidelobe level, sidelobe falloff, coherent gain, equivalent noise bandwidth, 3 dB bandwidth, scallop loss, worst case processing loss, 6 dB bandwidth, and overlap correlation. The paper covers 23 types of windows, some having sub-types constructed by different control parameter values, with data and pictures of each. Even if this paper is not useful for your particular problem, it's still a generally useful reference to have available. I find I have referred to it many times in the past 20 years. Many others reference it also, but the paper doesn't seem available on the web. -Alex [posted and emailed]
Reply by ●September 9, 20042004-09-09
Rick Lyons wrote:> On Tue, 07 Sep 2004 09:07:15 +0200, Bernhard Holzmayer > <holzmayer.bernhard@deadspam.com> wrote: > > (snipped) >> >>Sorry for the delayed question >>(holidays on the lake of Constance (Germany) were splendid!), > > (snipped) >> >>Bernhard > > Hello Bernhard, > > ah, you are breaking my heart! > > Lake Constance, ... I'd give almost anything to > sit with my feet in the lake, look at the surrounding > hills, and drink a local German pilsner beer! > > If there is no Lake Constance and no German pilsner > beer in heaven, then I don't want to go to heaven. > > [-Rick-]In any case, I'll be there, and I can share my memories with you. Indeed, I live only 90km away from the lake and some 100km from Constance. In reach for a one-day-journey.
