Jerry Avins wrote:> Eric Jacobsen wrote: >> Regarding the sampling theories, I'd agree that Shannon's contribution >> was pretty much just a restatement in terms of Information Theory. >> In Information Theory, though, he did more or less the equivalent of >> starting with whole cloth and producing the unified field theory. His >> foundations for information theory have been essentially unchallenged >> and unmodified until only the last few years. That's a pretty >> significant contribution, IMHO. ;) > > > I remember trying to understand popularizations of his work shortly > after he published. Exciting stuff!The original is actually more readable than most of the popularisations. Regards, Steve
An intriguing story about undersampling
Started by ●June 5, 2005
Reply by ●June 6, 20052005-06-06
Reply by ●June 6, 20052005-06-06
Jerry Avins wrote:> Carlos wrote: > >> Jerry Avins wrote: >> >>> Rimmer wrote: >>> >>>> "erine" <erine@hotmail.com> wrote in message >>>> news:_yxoe.134020$IN.2310899@twister2.libero.it... >>>> >>>> >>>>> Read this astonishing story at >>>>> http://spazioscuola.altervista.org/UndersamplingAR/UndersamplingAR.htm >>>>> Here it is an excerpt: >>>>> A STORY ABOUT UNDERSAMPLING >>>>> >>>>> by Angelo Ricotta - Rome, Italy >>>>> >>>>> a.ricotta@isac.cnr.it >>>>> >>>>> ITALIAN VERSION >>>>> >>>> >>>> If it aint done in the USA - forget it. >>> >>> >>> And here I thought everything had been invented in Russia! >>> >> >> >> Cheers!! What about little old us in the UK (remember, a small island, >> east >> of you!!). I'm sure we invented a few things too :-D > > > Make a list, and someone will claim priority for an obscure Russian.Britain invented concentration camps. Lets see if someone else wants to take credit for that. Regards, Steve
Reply by ●June 6, 20052005-06-06
Steve Underwood wrote:> Jerry Avins wrote: >> Carlos wrote: >> >>> Jerry Avins wrote: >>> >>>> Rimmer wrote: >>>> >>>>> "erine" <erine@hotmail.com> wrote in message >>>>> news:_yxoe.134020$IN.2310899@twister2.libero.it... >>>>> >>>>> >>>>>> Read this astonishing story at >>>>>>http://spazioscuola.altervista.org/UndersamplingAR/UndersamplingAR.htm>>>>>> Here it is an excerpt: >>>>>> A STORY ABOUT UNDERSAMPLING >>>>>> >>>>>> by Angelo Ricotta - Rome, Italy >>>>>> >>>>>> a.ricotta@isac.cnr.it >>>>>> >>>>>> ITALIAN VERSION >>>>>> >>>>> >>>>> If it aint done in the USA - forget it. >>>> >>>> >>>> And here I thought everything had been invented in Russia! >>>> >>> >>> >>> Cheers!! What about little old us in the UK (remember, a small >>> island, east >>> of you!!). I'm sure we invented a few things too :-D >> >> >> Make a list, and someone will claim priority for an obscure Russian. > > Britain invented concentration camps. Lets see if someone else wants > to take credit for that. >Term was first used by the Spanish in Cuba (1868-78) Also by the States in the Phillipines (1898-1901) Russians had a good go at them with their Gulags in the 1920s. Cheers, Carlos
Reply by ●June 6, 20052005-06-06
On 6 Jun 2005 02:38:56 -0700, "Andor" <an2or@mailcircuit.com> wrote:>What has been challenged in Information Theory in the last few years? > >(Genuine interest) > >Regards, >AndorAndor, It's not so much a challenge as a clarification of the limitations of Shannon's analysis. Shannon's capacity analysis was for a single use with a single user, and Multiple User Detection techniques and MIMO have both driven an expansion of Shannon's analysis to include multiple uses in the same channel. The results do differ from the single use case. Eric Jacobsen Minister of Algorithms, Intel Corp. My opinions may not be Intel's opinions. http://www.ericjacobsen.org
Reply by ●June 6, 20052005-06-06
On Mon, 06 Jun 2005 22:38:49 +0800, Steve Underwood <steveu@dis.org> wrote:>Jerry Avins wrote: >> Eric Jacobsen wrote: >>> Regarding the sampling theories, I'd agree that Shannon's contribution >>> was pretty much just a restatement in terms of Information Theory. >>> In Information Theory, though, he did more or less the equivalent of >>> starting with whole cloth and producing the unified field theory. His >>> foundations for information theory have been essentially unchallenged >>> and unmodified until only the last few years. That's a pretty >>> significant contribution, IMHO. ;) >> >> >> I remember trying to understand popularizations of his work shortly >> after he published. Exciting stuff! > >The original is actually more readable than most of the popularisations. > >Regards, >SteveI'd agree there. I think that's one of the things that makes it a great contribution: it was written to be understandable. To me that means the author really understood it well enough to convey it in an understandable fashion. I always suspect that many of the hard-to-read papers that go around really just reflect that the author didn't understand it, either. Eric Jacobsen Minister of Algorithms, Intel Corp. My opinions may not be Intel's opinions. http://www.ericjacobsen.org
Reply by ●June 6, 20052005-06-06
Eric Jacobsen wrote:> On Mon, 06 Jun 2005 22:38:49 +0800, Steve Underwood <steveu@dis.org> > wrote: > > >>Jerry Avins wrote: >> >>>Eric Jacobsen wrote: >>> >>>>Regarding the sampling theories, I'd agree that Shannon's contribution >>>>was pretty much just a restatement in terms of Information Theory. >>>>In Information Theory, though, he did more or less the equivalent of >>>>starting with whole cloth and producing the unified field theory. His >>>>foundations for information theory have been essentially unchallenged >>>>and unmodified until only the last few years. That's a pretty >>>>significant contribution, IMHO. ;) >>> >>> >>>I remember trying to understand popularizations of his work shortly >>>after he published. Exciting stuff! >> >>The original is actually more readable than most of the popularisations. >> >>Regards, >>Steve > > > I'd agree there. I think that's one of the things that makes it a > great contribution: it was written to be understandable. To me that > means the author really understood it well enough to convey it in an > understandable fashion. I always suspect that many of the > hard-to-read papers that go around really just reflect that the author > didn't understand it, either.In 1948, I was a junior in high school; I has no easy access to the Bell System Journal. The lucid science articles in, Astounding Science Fiction (of all places) were a frequent source of solid information. I was in Boy Scout camp a few years earlier when someone tuning a radio from one station to another stopped briefly at a point between. I heard the words "atomic bomb" and went nuts. I pushed the guy out of the way and tried to get the station back, without success. I was so intense that nobody interfered. When I gave up, I had to explain: "I thought I heard "atomic bomb". I got blank stares and "So?" I answered, "If I'm right, the war is over. I want to know who won." Then they _knew_ I was nuts, if good natured. The next morning, when the newspapers arrived at camp, even the scoutmaster wanted to know how I had known. I could only answer "ASF". (The same mag that touted the Hieronymus machine) Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●June 6, 20052005-06-06
"Eric Jacobsen" <eric.jacobsen@ieee.org> wrote in message news:hh69a1puu2ndmu2i724iphvbj9tgpbb5ct@4ax.com...> On 6 Jun 2005 02:38:56 -0700, "Andor" <an2or@mailcircuit.com> wrote: > > >What has been challenged in Information Theory in the last few years? > > > >(Genuine interest) > > It's not so much a challenge as a clarification of the limitations of > Shannon's analysis. Shannon's capacity analysis was for a single > use with a single user, and Multiple User Detection techniques and > MIMO have both driven an expansion of Shannon's analysis to include > multiple uses in the same channel. The results do differ from the > single use case.I also remembering seeing a bunch of noise about 56K modems being able to exceed the Shannon theoretical channel limit a few years back, including I think a thread here on comp.dsp. But upon closer examination, I think there were some assumptions that Shannon made that didn't apply to the modem scenario (the noise being white and Gaussian maybe?).
Reply by ●June 6, 20052005-06-06
Jon Harris wrote:> "Eric Jacobsen" <eric.jacobsen@ieee.org> wrote in message > news:hh69a1puu2ndmu2i724iphvbj9tgpbb5ct@4ax.com... > >>On 6 Jun 2005 02:38:56 -0700, "Andor" <an2or@mailcircuit.com> wrote: >> >> >>>What has been challenged in Information Theory in the last few years? >>> >>>(Genuine interest) >> >>It's not so much a challenge as a clarification of the limitations of >>Shannon's analysis. Shannon's capacity analysis was for a single >>use with a single user, and Multiple User Detection techniques and >>MIMO have both driven an expansion of Shannon's analysis to include >>multiple uses in the same channel. The results do differ from the >>single use case. > > > I also remembering seeing a bunch of noise about 56K modems being able to exceed > the Shannon theoretical channel limit a few years back, including I think a > thread here on comp.dsp. But upon closer examination, I think there were some > assumptions that Shannon made that didn't apply to the modem scenario (the noise > being white and Gaussian maybe?).Basically, channel capacity depends not only on bandwidth, but also on SNR. With a high enough resolution, you can encode the entire Library of Alexandria in the length of short piece of Invar. When the line gets a wee bit noisy, those 56K modems slow down. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●June 6, 20052005-06-06
Jerry Avins wrote:> [snip] The lucid science articles in, Astounding Science Fiction ... > > ... I could only > answer "ASF". (The same mag that touted the Hieronymus machine)and timoline [sp????] ie "slow glass" But I thought that was _Analog_ in Campbell era.
Reply by ●June 6, 20052005-06-06
"Jerry Avins" <jya@ieee.org> wrote in message news:ys2dnSRg3ph4MjnfRVn-gw@rcn.net...> Jon Harris wrote: > > "Eric Jacobsen" <eric.jacobsen@ieee.org> wrote in message > > news:hh69a1puu2ndmu2i724iphvbj9tgpbb5ct@4ax.com... > > > >>On 6 Jun 2005 02:38:56 -0700, "Andor" <an2or@mailcircuit.com> wrote: > >> > >> > >>>What has been challenged in Information Theory in the last few years? > >>> > >>>(Genuine interest) > >> > >>It's not so much a challenge as a clarification of the limitations of > >>Shannon's analysis. Shannon's capacity analysis was for a single > >>use with a single user, and Multiple User Detection techniques and > >>MIMO have both driven an expansion of Shannon's analysis to include > >>multiple uses in the same channel. The results do differ from the > >>single use case. > > > > > > I also remembering seeing a bunch of noise about 56K modems being able toexceed> > the Shannon theoretical channel limit a few years back, including I think a > > thread here on comp.dsp. But upon closer examination, I think there weresome> > assumptions that Shannon made that didn't apply to the modem scenario (thenoise> > being white and Gaussian maybe?). > > Basically, channel capacity depends not only on bandwidth, but also on > SNR. With a high enough resolution, you can encode the entire Library of > Alexandria in the length of short piece of Invar. When the line gets a > wee bit noisy, those 56K modems slow down.Yes, that is the essence of Shannon's theorem. The modem article claimed to exceed the "Shannon capacity" of a phone line, IIRC. Upon closer examination, it didn't.
