maxplanck wrote:>> From those 5000 "clean" cycles, you can very accurately determine the >> frequency. It will turn out to be *exactly* the frequency you assumed >> when you arbitrarily selected the single segment to duplicate. > > Isn't the goal to determine what combination of sine waves will most > closely reproduce the original signal? If so, doesn't this meet that > criteria, at least for this particular segment of the signal?When you chose the segment, you lock in the result. "The rest is commentary."> I've tried looping the region between every other zero crossing of an > audio signal (loop starts @ zero crossing, positive portion, zero crossing, > negative portion, loop ends @ zero crossing) and then running an FT on that > loop, and the resulting spectrum is way different from the spectrum I get > for that region when I run the whole signal through a STFT analyzer such as > SPEAR, so I can see from this that looping regions is not useful. > > I suppose I should read more about the STFT, that would probably clear up > why looping individual regions is useless.If there are two components not precisely harmonically related, then there are no duplicated regions between zero crossings anywhere in the signal. Plot f(t) = sin(wt) + sin (pi*wt). It will repeat *approximately* every 154 zero-crossing intervals, more accurately every 40,115. Never exactly, though. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Looking for a GOOD explanation of the proof and application of DST, and other DSP techniques.. DSP encyclopedia?
Started by ●May 29, 2008
Reply by ●May 30, 20082008-05-30
Reply by ●May 30, 20082008-05-30
>If there are two components not precisely harmonically related, then >there are no duplicated regions between zero crossings anywhere in the >signal. Plot f(t) = sin(wt) + sin (pi*wt). It will repeat >*approximately* every 154 zero-crossing intervals, more accurately every>40,115. Never exactly, though. > >Jerry >-- >Engineering is the art of making what you want from things you can get. >�����������������������������������������������������������������������This makes sense, I think you told me that before in another thread, makes more sense hearing it a second time after the first one had time to marinate. Thanks!
Reply by ●May 31, 20082008-05-31
On May 29, 10:22�am, "maxplanck" <erik.bo...@comcast.net> wrote:> I was reading some tutorials @ dspdimension.com, and they were talking > about techniques that I'd never heard of before, such as the Discrete Sine > Transform. �The explanation was understandable if the reader does a lot of > thinking, but more diagrams and possibly even animations would convey the > concepts more clearly and require much less time from the reader. > (Although to be fair, it seems like almost no authors of technical material > go to these lengths.. kind of a shame I think.. I think it was Feynman who > said something like "For anything we really understand, we should be able > to craft an explanation that even a child can understand.") > Explaining the proof would probably clear up any lingering > doubts/undiscussed logical holes in the readers mind, provided that the > proof is presented in a clear manner accompanied by plenty of diagrams > and/or animations.. but this is outside the scope of the tutorial.The best teacher is a student who just learned the topic, unfortunately they don't write books. That is, until 20 years later when they forgot everything they didn't know! At this point simply listing a proof is sufficient in their minds as equivalent to teaching the subject and I have never been able to convince authors otherwise. It appears their primary audience are their colleagues (who usually proof read it ), and that is the way they write it, more of refresher text, directed to people who knew the subject beforehand. Feynman was guilty of this as anyone else. Just the way it is.
Reply by ●May 31, 20082008-05-31
>At this point simply listing a proof is sufficient in their minds as >equivalent to teaching the subject and I have never been able to >convince authors otherwise. It appears their primary audience are >their colleagues (who usually proof read it ), and that is the way >they write it, more of refresher text, directed to people who knew the >subject beforehand.yes! More detailed in depth explanations take more time, and most professors are strapped for time.. Have you ever read or listened to Feynman's "6 Easy Pieces?" Pretty well done imo
Reply by ●May 31, 20082008-05-31
steve wrote:> On May 29, 10:22 am, "maxplanck" <erik.bo...@comcast.net> wrote: >> I was reading some tutorials @ dspdimension.com, and they were talking >> about techniques that I'd never heard of before, such as the Discrete Sine >> Transform. The explanation was understandable if the reader does a lot of >> thinking, but more diagrams and possibly even animations would convey the >> concepts more clearly and require much less time from the reader. >> (Although to be fair, it seems like almost no authors of technical material >> go to these lengths.. kind of a shame I think.. I think it was Feynman who >> said something like "For anything we really understand, we should be able >> to craft an explanation that even a child can understand.") >> Explaining the proof would probably clear up any lingering >> doubts/undiscussed logical holes in the readers mind, provided that the >> proof is presented in a clear manner accompanied by plenty of diagrams >> and/or animations.. but this is outside the scope of the tutorial. > > The best teacher is a student who just learned the topic, > unfortunately they don't write books. That is, until 20 years later > when they forgot everything they didn't know! > > At this point simply listing a proof is sufficient in their minds as > equivalent to teaching the subject and I have never been able to > convince authors otherwise. It appears their primary audience are > their colleagues (who usually proof read it ), and that is the way > they write it, more of refresher text, directed to people who knew the > subject beforehand. Feynman was guilty of this as anyone else. Just > the way it is.There are some teachers who who keep an understanding of what beginners can find hard about a subject even years after they become expert. Those teachers are rare, but I know a few. Rick Lyons is one. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●May 31, 20082008-05-31
On May 31, 10:25�am, "maxplanck" <erik.bo...@comcast.net> wrote:> >At this point simply listing a proof is sufficient in their minds as > >equivalent to teaching the subject and I have never been able to > >convince authors otherwise. It appears their primary audience are > >their colleagues (who usually proof read it ), and that is the way > >they write it, more of refresher text, directed to people who knew the > >subject beforehand. � > > yes! �More detailed in depth explanations take more time, and most > professors are strapped for time.. > > Have you ever read or listened to Feynman's "6 Easy Pieces?" �Pretty well > done imoindirectly, we used the Feynman lecture series when I was a student at Princeton ages ago, which I believe the "easy pieces" were derived from. But, at the time, I found I needed to read an older tradition physics textbook before reading the lecture series.
Reply by ●June 2, 20082008-06-02
On May 31, 5:09�pm, steve <bungalow_st...@yahoo.com> wrote:> On May 31, 10:25�am, "maxplanck" <erik.bo...@comcast.net> wrote: > > > >At this point simply listing a proof is sufficient in their minds as > > >equivalent to teaching the subject and I have never been able to > > >convince authors otherwise. It appears their primary audience are > > >their colleagues (who usually proof read it ), and that is the way > > >they write it, more of refresher text, directed to people who knew the > > >subject beforehand. � > > > yes! �More detailed in depth explanations take more time, and most > > professors are strapped for time.. > > > Have you ever read or listened to Feynman's "6 Easy Pieces?" �Pretty well > > done imo > > indirectly, we used the Feynman lecture series when I was a student at > Princeton ages ago, which I believe the "easy pieces" were derived > from. But, at the time, I found I needed to read an older tradition > physics textbook before reading the lecture series.Don't forget it was Leighton and Sands who cleaned up and put the "lectures" into a clean book form. Feynman was one of the greats, but books and lectures tend to be quite different and books need to be more formal. Clay
Reply by ●June 5, 20082008-06-05
On Thu, 29 May 2008 20:34:40 -0700 (PDT), steveu@coppice.org wrote:>On May 30, 1:22 am, "maxplanck" <erik.bo...@comcast.net> wrote: > >> I read Lyons' "Understanding Digital Signal Processing," I thought it did >> a very good job of explaining the material that it covered.. but it seems >> like there is so much out there that it didn't cover. It didn't get into >> proofs either, which would have been nice but is just outside the scope of >> the book. > >I've seen estimates that there are about 50,000 DSP engineers in the >world. I have no idea how those estimates are arrived at, or what they >class as a DSP engineer - Someone who touches a little DSP from time >to time? Someone who programs the stuff all day, but has a weak >understanding of the principals? Someone who cooks up the deepest of >algorithms for fun and profit? Anyway, its not a huge number, but its >enough that they are working is a heck of a lot of application areas. > >I finally got a copy of Rick Lyons book recently. Since the local >retail price is RMB59 (about US$8), it didn't add much to the bill >when I noticed it while buying something else. :-) People have been >recommending this book heavily for ages, and now I see why. I think it >strikes an excellent balance for an introductory text. If it included >the proofs of everything it covers, it would get bogged down in no >time. If it tried to focus on a lot of application specifics, it would >get bogged down even faster. I think its a great first book. It is a >first book, though. Most signal processing books are considerably >thicker, while covering one narrow subject matter, and leaving out >most of the juicy details that lead to successful applications. :-) >Its interesting how even the thickest signal processing books, on the >narrowest of topics, are still only able to skim over the subject >matter. Our job must be HUGE! :-) > >Regards, >SteveHi Steve, Thanks for the kind words. Here's an offer to you, and maxplanck as weel. If you have an American version of my "Understanding DSP" book, I can send you the errata for the book if you can tell me the "Printing Number" of your copy of the book. You can determine the "Printing Number" of the American version (ISBN# 0-13-108989-7) of the 2nd Edition of my book by looking at the page just before the "Dedication" page. On that page (before the Dedication) you'll see all sorts of publisher-related information, including the ISBN number. Down toward the bottom of the page you should see lines printed something like: Printed in the United States of America First Printing indicating the "First Printing" of the book. However, for later printings the second line above may have the words like: "Second Printing" or "Seventh Printing". Regards, [-Rick-]
