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The Rust of the Story
On Sun, 09 Mar 2008 21:13:54 -0500, Mike Coslo
wrote: Coherent light is not the half of it! We are both more and less advanced than we might think. Hi Mike, Coherence has become a shallow rhyming proof rendered as "SoThereIt's!" (a mumbled qed). It is a convenience of a special solution which requires artificial constraints that over the course of "debate" have become necessary correlatives to a general "law" of optics. In fact, few have examined what "coherence" actually means, but instead it has been Xeroxed by Cecil into the argument. Both Mike and Tom have been able to disconnect this term as one of necessity for monochromaticity (not required) and instantaneity (also not required). This lack of requirement (that requirement having been artificially injected into the discussion) is historically exhibited in work going beyond 100 years old. The first work was with sun/starlight that is neither pulsed nor monochromatic, and yet and all, interference was clearly found which led us to this discussion. Even though the classic hologram, developed 60 years ago, or so, was originally monochromatic; it didn't take much more effort to accomplish the same photography with white light (1968). Wide band sources can demonstrate interference as readily there as with the original Michelson-Morely interferometer. In fact, most here need only open their wallet to examine a credit card or driver's license to prove this to themselves under a common table lamp. Coherence (cross-correlating) is a statistical term for comparing (0.00 to 1.00) complex waves. You can have temporal coherence, spacial coherence, spectral coherence and on and on; none of which are actually named here, but whose various definitions have been notoriously cross-connected into a hodge-podge argument of no particular merit. If we delve into the merits of sun/starlight, we eventually narrow on into the distinction of these terms of spatial and temporal coherence and the coherent area/length/volume (where incoherent sunlight is found to be coherent within 0.02mm) and then into what has already been identified by Gene with partial coherence (a topic that Wolf pursued, and at which Born hesitated). 73's Richard Clark, KB7QHC |
#2
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The Rust of the Story
Richard Clark wrote:
Coherence (cross-correlating) is a statistical term for comparing (0.00 to 1.00) complex waves. You can have temporal coherence, spacial coherence, spectral coherence and on and on; none of which are actually named here, but whose various definitions have been notoriously cross-connected into a hodge-podge argument of no particular merit. Fortunately, we amateur radio operators are not concerned with anything that complex. We are concerned with essentially single frequency, phase-locked signals in a single-source, single transmission line, single-load configuration. Many levels and dimensions of complexity simply are negligible concerns within the amateur radio environment. Introducing irrelevant issues is just a diversion away from ideal examples which are relatively easy to understand. Isn't it better to clear the waters rather than muddy them? -- 73, Cecil http://www.w5dxp.com |
#3
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The Rust of the Story
On Mon, 10 Mar 2008 08:19:02 -0500, Cecil Moore
wrote: Isn't it better to clear the waters rather than muddy them? I agree, you don't know the difference well enough to differentiate silt from mud from glacial flour - and yet you offer your fortified kool-ade. Your food coloring, sugar, and added special ingredients doesn't bring clarity (and as any nutritionist would say: sugar is empty calories). |
#4
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The Rust of the Story
Richard Clark wrote:
Cecil Moore wrote: Isn't it better to clear the waters rather than muddy them? I agree, you don't know the difference well enough to differentiate silt from mud from glacial flour - and yet you offer your fortified kool-ade. Actually, I am using ohm's law instead of string theory. -- 73, Cecil http://www.w5dxp.com |
#5
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The Rust of the Story
On Mon, 10 Mar 2008 17:35:01 GMT, Cecil Moore
wrote: Actually, I am using ohm's law instead of string theory. To respond to the topic of Coherence.... Neither shocking nor a surprise as it's as though I were reading the last pages of "Flowers for Algernon." May as well leave it as that. |
#6
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The Rust of the Story
Richard Clark wrote:
Cecil Moore wrote: Actually, I am using ohm's law instead of string theory. To respond to the topic of Coherence.... Neither shocking nor a surprise as it's as though I were reading the last pages of "Flowers for Algernon." If Mr. Ohm introduced his law today, he would be belittled because it is not a theory of everything. -- 73, Cecil http://www.w5dxp.com |
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