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It is very complicated and depends a lot on the size and type of fiber as to its functioning.I have read this article and it seems to be pretty informative . The info must be carried through the light through out the plastic or glass lines.Any way here you go. It doesn't answer all of your questions but some!http://en.wikipedia.org/wiki/Optical_fiber
George what do you mean by smear out.. do you mean for the light to ade or deminish?? I don't understand the term?
I still don't understand how it keeps from getting scrambled as Neil asked earlier.....
How Much data can a strand of this carry ?
QuoteHow Much data can a strand of this carry ? i suppose that would depend on how small the lettering was in the books you hang from it. 
I think that a strand of optical fibre can be made to carry just about as much data as you want; eventually.
I still don't understand how it keeps from getting scrambled as Neil asked earlier.....Your welcome Neil Thanks for all the new topics they are great!
Quote from: Karen W. on 01/10/2007 09:34:22I still don't understand how it keeps from getting scrambled as Neil asked earlier.....Your welcome Neil Thanks for all the new topics they are great!I am not sure what you mean by scrambled?The issues about blurring (the spreading out of the wave) have been addressed, but ignoring those issues (assuming that the fibres were optically perfect, and very thing, and had equal properties for all frequencies), then it is simply a matter of first in first out (the data will come out of the fibre in the same sequence it went in).
"Well, no - you cannot get around the nyquist limit (although we are presently well short of that limit)."I may have misunderstood, but I thought that Nyquist's work showed that the rate o data transfer was limited, not the quantity. If you want you can send all the data you have. It may take a long time if you have a lot of data or a poor bandwidth, but you can do it eventually.
We all use data compression when we send files to each other. To get the maximum useful information rate across, you need to take a lot of delay in the system. This allows you to code the information efficiently and to check and correct errors. It's fiendishly complicated but 'they' are making advances all the time. It's why you can get such a lot of programme time on a DVD or MP3 player, these days. Present systems still waste a lot of channel capacity because the coding is not ideal. It gets better all the time, however.
THANK EWE again for your continued wonedrful posts !!May I ask please what a NYQUIST limit is?.
Nyquist rateIn 1927, Nyquist determined that the number of independent pulses that could be put through a telegraph channel per unit time is limited to twice the bandwidth of the channel. In symbols,where fp is the pulse frequency (in pulses per second) and B is the bandwidth (in hertz). The quantity 2B later came to be called the Nyquist rate, and transmitting at the limiting pulse rate of 2B pulses per second as signalling at the Nyquist rate. Nyquist published his results in 1928 as part of his paper "Certain topics in Telegraph Transmission Theory."
and does it have anything to do with a flavoured milk drink?
NYQUIST limit?!?!?!I have a friend who's last name is Nyquist (a quite commen Swedish name I believe).
Harry Nyquist (February 7, 1889 – April 4, 1976) was an important contributor to information theory.He was born in Nilsby, Sweden. He emigrated to the USA in 1907 and entered the University of North Dakota in 1912. He received a Ph.D. in physics at Yale University in 1917. He worked at AT&T's Department of Development and Research from 1917 to 1934, and continued when it became Bell Telephone Laboratories in that year, until his retirement in 1954.As an engineer at Bell Laboratories, he did important work on thermal noise ("Johnson–Nyquist noise"), the stability of feedback amplifiers, telegraphy, facsimile, television, and other important communications problems. With Herbert E. Ives, he helped to develop AT&T's first facsimile machines that were made public in 1924. In 1932, he published a classical paper on stability of feedback amplifiers (H. Nyquist, "Regeneration theory", Bell System Technical Journal, vol. 11, pp. 126-147, 1932). Nyquist stability criterion can now be found in all textbooks on feedback control theory.His early theoretical work on determining the bandwidth requirements for transmitting information, as published in "Certain factors affecting telegraph speed" (Bell System Technical Journal, 3, 324–346, 1924), laid the foundations for later advances by Claude Shannon, which led to the development of information theory.In 1927 Nyquist determined that the number of independent pulses that could be put through a telegraph channel per unit time is limited to twice the bandwidth of the channel. Nyquist published his results in the paper Certain topics in Telegraph Transmission Theory (1928). This rule is essentially a dual of what is now known as the Nyquist–Shannon sampling theorem.Nyquist received the IRE Medal of Honor in 1960 for "fundamental contributions to a quantitative understanding of thermal noise, data transmission and negative feedback." In October 1960 he was awarded the Stuart Ballantine Medal of the Franklin Institute "for his theoretical analyses and practical inventions in the field of communications systems during the past forty years including, particularly, his original work in the theories of telegraph transmission, thermal noise in electric conductors, and in the history of feedback systems." In 1969 he was awarded the National Academy of Engineering's fourth Founder's Medal "in recognition of his many fundamental contributions to engineering."Nyquist lived in Pharr, Texas after his retirement, and died in Harlingen, Texas on April 4, 1976.
THANK EWE again for your continued wonedrful posts !!May I ask please what a NYQUIST limit is?...and does it have anything to do with a flavoured milk drink?
As I remember, the Nyquist limit relates to the sample rate needed to re-construct a signal, perfectly. The limit is two samples for the the highest rate.
Karen WI like your technical stuff but I have a problem with your picture of Nestle products. They (Nestle) are playing hell with the third world health by marketing formula milk where it is not safe to use because the available water is poor quality - they are 'dissing' breastfeeding in an area where it provides a useful barrier against disease for small babies.Not relevant to Nyquist but I thought I'd get it off my chest. Is this too political?
The actual capacity of a channel - which is what you would like to maximise, when you are paying for a satellite link, for instance, relates to the total information you can get through each Hz of available bandwidth. This is very much limited by the signal to noise ratio.
I have to disagree with you on what is implied by the 'Nyquist rate'. There is no reference to the number of levels in the samples to which Nyquist refers. It certainly doesn't only restrict things to two levels. You can have as many levels as you like for your samples - they can, of course, even be analogue samples. Nyquist just says that you need > = two samples per second per Hz of the highest frequency in the baseband signal. That is all.
but this does not make for infinite numbers of signals
because any modulation of the carrier will create sidebands,
Additionally, the light signals propagating in the fiber can be modulated at rates as high as 40 Gb/s , and each fiber can carry many independent channels,