Hi A real simple question that has puzzled me too long. In terms of a phase accumulator. a constant frequency out Fout , is a constant phase increment, New phase = old phase + phase constant For a linear up sweep of Fout new Phase = old phase + ( phase constant * N) where N is an integer, increases by 1 on each iteration So for a log sweep ? new phase = old phase + ( ??? ) so what do I put in for ???