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Hi, i'm new in TopSpin and i am blocked by a simple (i thinks) problem. I have a 1D specrtrum and i would like to export it to excel or origin but my spectrum have a small S/N so there is to much point --> i want this spectrum with less point but without smoothing (if it's possible). In other word, how can i do to tell TopSpin "get the spectrum but only every 10 points (or X points)" ?

Thank you in advance for those who will have the kindness to answer.

asked Jun 29 '11 at 02:25

Assma%20El's gravatar image

Assma El
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Hi Assma,

This is a confusing question. What do you want? If you want a better spectrum with less noise, then you need to re-run the spectrum longer, or with more sample.

The other (cheat) way to do it is to reduce the number of points that TopSpin uses for the Fourier Transform. This will improve your signal to noise by focusing on the data signal and not the noise signal, but will reduce your resolution though. You can do this without re-running the spectrum by adjusting the 'TDeff' variable in the processing tab. Make this half the number of points, for example - (by the way - '0' in TopSpin often means 'use all' or 'infinite'). The other thing to check is that you aren't overusing 'zero-filling', which will just add points to your spectrum without giving you any more resolution. This is the value that is called 'SI' in the processing tab - it should be the smallest binary number (i.e. 2,4,8,16,32,64,128...) that is bigger than 'TD' in your acquisition parameters. There is also things you can do with window functions (such as line broadening using an exponential function), but if you are unfamiliar with NMR then it is probably best not to go into that here.

Finally, if TopSpin isn't your thing, but you are using Excell or Origin, why don't you just import the spectral points, but use a formula or macro to copy only every tenth point? In Excell you could do this by calling " =INDEX($A$x:$A$y,(ROW()-1)*n+1) ", where you replace x by the first row number, and y by the last (and your data list is in column A), and n by 10 if you want every tenth value. Pop this in and you will get the values for row A1, A11, A21 in rows 1, 2, and 3. You can then copy the 'values' not the formula into another sheet or workbook so that Excell won't run as slow before you start making a graph.

Hope this helps - TJ

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answered Aug 14 '11 at 20:57

TJCarruthers's gravatar image

TJCarruthers
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Asked: Jun 29 '11 at 02:25

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Last updated: Aug 14 '11 at 20:57

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