Sean Schouten wrote... >As for the use of a simple RC-filter; Say I would use a simple RC filter, >then pass the signal trough an opamp to add some gain to the story, would >the amplified output have a constant peak-to-peak value throughout the >frequency range? It should, provided a) you choose an appropriate opamp-- mainly, one that is sufficiently fast that it won't distort the signal by slew-rate limiting (as you saw in your simulation), and b) your filter cutoff frequency is at least several times the maximum frequency of the sinewave; otherwise, the amplitude will begin to drop as you get up near the maximum frequency. Dave D. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist