Problems while using Interpolation function

Dear colleagues,

I am trying to use the data output from a Matlab program as a source in my coefficient form PDE using the interpolation function. The data is being distorted by the interpolation function (defined in Global definitions). I am losing the peaks. Please see attachment for how the data looks in Excel vs COMSOL interpolation function. I tried all options in the interpolation and extrapolation drop down menus but unable to obtain a waveform similar to the source.

Any suggestions or ideas to extract the correct waveform into COMSOL?

PS: The original data source had 10000 data points which I could not import into COMSOL. I reduced the dataset to 1600 points without losing the waveform shape and was able to import into COMSOL but not as expected.

Thanks
Deepika