I am resending this as I think it didn't get through the first time. My
apologies if I am mistaken and this was already sent.
Thanks to all who responded to my question. I have received more than 10
answers in a few hours. Most of them suggested using linear prediction. My
corrupted FID is about 39000 complex points long and the bad points occur at
about 12400, right in the middle of good data. Although I knew about linear
prediction, I didn't want to use it because I didn't want to loose all the
signal that was collected after the bad points. I was only thinking about
backward and forward LP before and after the FID data. It didn't occur to me
that you can predict just a few points in the middle of the FID to substitute
the bad points. After adjusting the parameters (thank you for the
suggestions) the two glitches completely disappeared and was able to get a
decent spectrum.
By the way, only the real part of the two points were corrupted and it hasn't
happened before (or after) on this instrument.
Best regards.
On Friday 26 August 2005 04:00 pm, Eugenio Alvarado wrote:
> Dear friends,
>
> A user at our facility has collected a C13 spectrum whose FID contains two
> very large, single point glitches in the middle. The FID took several
> hours to acquire and looks fine otherwise. So my question is, Does anyone
> know of a program that allows me to change the intensity of any point in an
> FID to any value I want? Ideally I would like to read the FID (Varian
> format) with some kind of editor and write it back in the same format so it
> can be processed with the standard vnmr software. Or any other processing
> program that can import vnmr data and alter it before FT?
>
> Thank you.
--
Eugenio Alvarado
Co-Director, NMR Services
Chemistry Department
University of Michigan
-------------------------------------------------------
--
Eugenio Alvarado
Co-Director, NMR Services
Chemistry Department
University of Michigan
Received on Mon Sep 12 2005 - 09:44:44 MST