Hmmm, I may be missing something but.. I can't get any result out of the IIR filtering, nor the raw samples, nor their average... Well, I simulated 20 samples (one full sine wave) on an Excel spreadsheet, and tried shifting the sine with respect to the sampling point, and the result does change a lot - not good. Can you suggest where I'm going wrong? thx! -- Ciao, Dario -- Cyberdyne -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist