Hi rgagler,   Are you still interested applying lowpass filtering to your data set?  SAS now has full support of digital filtering (lowpass, highpass, bandpass and bandstop) in the products (including filter design and applying the filter to the data).    Digital filtering is supported in the following products: 1) Through the IML procedure starting from SAS/IML® 15.1.  (Butterworth filter) 2) Through SAS® Cloud Analytic Services (CAS) and SAS® Event Stream Processing starting from SAS® 9.4M6.   (Butterworth, Chebyshev Type I and Type II filters)   You can find the detailed documentation on using digital filtering through IML here:  https://go.documentation.sas.com/?docsetId=imlug&docsetTarget=imlug_langref_sect013.htm&docsetVersion=15.1&locale=en   Please let me know if you have further question.    Thanks Yuwei Liao       ... View more