# How to analyze all the data in a directory

I am trying to import, analyze, and save all the .txt files in a specific directory. I can do this with a single .txt file using the following code:

data= Import["D:Experiments\\raw-data.txt", "Table"];
range = Select[data, 400 < #[[1]] < 550 &];
smooth = Interpolation[range, InterpolationOrder -> 3];
ex = Table[{x,smooth[x]}, {x, 400, 550, 0.050}];
Export["D:Experiments\\raw-data-out.txt", ex, "Table"];


Could you help me how to perform this process for all the .txt files in my specific directory at once?

SetDirectory["D:Experiments\\"];