> Harold, > > What you describe is an exponential decline (0.5, 0.25, 0.125, etc.) > and this is a first-order IIR low pass filter. > > Sean Oops! You're right! Harold --=20 FCC Rules Updated Daily at http://www.hallikainen.com - Advertising opportunities available! --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .