vibrio
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Registered: 28th Feb 01
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for my PhD I need to understand the Fourier transform in order to convert time domain data to frequency domain data.
anyone care to offere a simple explantion
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MikeD
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Registered: 18th Aug 02
Location: Whittlesey, Cambridgeshire
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the answer is 3 i think
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Bram
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Registered: 25th Mar 02
Location: Derby
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I'll just dig my Casio Calculator watch out..........
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corsa_godfather
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Registered: 6th May 03
Location: Greenock,Scotland
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.3 x 9 6's of a decimal minus a wet sock
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Graeme
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Registered: 26th Jul 04
Location: Northampton
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quote:
Originally posted by MikeD
the answer is 3 i think
no its 4 mate, close but no cigar for u!! 
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Jake
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Registered: 24th Jan 05
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care to ellaborate the equation?
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Ian
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Registered: 28th Aug 99
Location: Liverpool
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quote:
Originally posted by vibrio
anyone care to offere a simple explantion
Yes, the peaks on your time graph are what will feature in your distribution.
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vibrio
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Registered: 28th Feb 01
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quote:
Originally posted by jake
care to ellaborate the equation?
not got a scooby the computer does it all for you when you get the readings from the NMR machine but felt I should at least try to understand it. you get the info from the NMR as a sin wave and the FT changes that into a graph with peaks to give you your spectra
Modern pulse NMR is performed exclusively in the Fourier transform mode. Of course it is useful to appreciate the advantages of the transform, and particularly the spectacular results which can be achieved by applying it in more than one dimension, but it is also essential to understand the limitations imposed by digital signal analysis. The sampling of signals, and their manipulation by computer, often limit the accuracy of various measurements of frequency and amplitude, and may even prevent the detection of signals altogether in certain cases. These are not difficult matters to understand, but they often seem rather abstract to newcomers to FT NMR. Even if you do not intend to operate a spectrometer, it is irresponsible not to acquire some familiarity with the interaction between parameters such as acquisition time and resolution, or repetition rate, relaxation times and signal intensity. Many errors in the use of modern NMR arise because of a lack of understanding of its limitations
[Edited on 30-10-2005 by vibrio]
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Ian
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Registered: 28th Aug 99
Location: Liverpool
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quote:
Originally posted by vibrio
it is irresponsible to try and acquire some familiarity with the interaction between parameters such as acquisition time and resolution, or repetition rate, relaxation times and signal intensity on a car web site.
Yeah, big problem.
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vibrio
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Registered: 28th Feb 01
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quote:
Originally posted by Ian
quote:
Originally posted by vibrio
it is irresponsible to try and acquire some familiarity with the interaction between parameters such as acquisition time and resolution, or repetition rate, relaxation times and signal intensity on a car web site.
Yeah, big problem.
LMFAO - to be fair I only posted it because of
quote:
Originally posted by Ian
I was just getting in to that 
next time I'll not bother trying 
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Jake
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Registered: 24th Jan 05
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what's the verdict, Ian?
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Ian
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Registered: 28th Aug 99
Location: Liverpool
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What the hell are you sampling anyway?
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vibrio
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quote:
Originally posted by Ian
What the hell are you sampling anyway?
protein called MBD2 whic forms part of the MeCP1 protein complex which specifically binds methylated CpG DNA sequence- which has implication in cancer as when you knock it out rates are resistant to developing cancer downside is they become bad mothers lol. if you can show how it binds to the DNA you can design a drug to block it.
[Edited on 30-10-2005 by vibrio]
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Dan B
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Registered: 25th Feb 01
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http://mathworld.wolfram.com/FourierTransform.html
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Edd
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Registered: 8th Nov 04
Location: Glasgow
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maths my only weakness
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