Fourier Transform NMR:

The intensity of NMR signal is proportional to the concentration of the absorbing species. Many a times we come across situations where the amount of sample available for analysis is too small; especially in case of biological samples. In such cases the signal to noise ratio is very small and it becomes difficult to distinguish the signal from the background noise. The way out is to 'scan' the sample a number of times and add the different scans along with the help of a computer. In this process the signal being at the same frequency every time adds up whereas the noise being random in nature gets cancelled out. That improves the signal to the noise ratio, thus taking a number of scans is quite time consuming. For instance, if one scan could be completed in about one minute, we would required more than an hour to record a meaningful spectrum.  A way out is provided by an important process called Fourier transformation.  Now let us learn about this.