I have done experiements on a grinding machine and have collected the data of grinding wheel profile (using a laser sensor). The raw data consists of info on grinding wheel profile, waviness and roughness (because of abrasive grains). I would like to process the colelcted raw data. I want to filter out the high frequency and low frequency data. (I want to appply a simple band pass filter). Each cycle consists of about 200,000 data units and I have them in an excel file(csv data) and would like to perform digital filtering. How do I filter out the waviness data separately and analyze, from this?