Hi there, Mario. Have a look at something called a "lock-in amplifier". A brief=20 overview can be found on WikipediA=20 dwayne At 12:03 PM 12/12/2011, Electron wrote: >Hello, >I have to get the *exact* timing (30ns resolution) of some low=20 >frequency (<250Hz) pulses >via an input capture module, however I'd like to filter the signal=20 >coming in, as it will >contain a lot of high frequency noise, but filtering via a capacitor=20 >introduces a phase >delay, which I can't even compensate (by frequency) as the phase=20 >delay changes with input >signal amplitude. > >What is the way You'd approach this problem? I thought about using a=20 >zener to clip the >signal and thus work on a known amplitude, but I suspect it will=20 >introduce errors too. > >On the software side, I could make sure that the input stays high=20 >for enough time, but >it's pretty overkill, and I'd like to keep it as last option. If it=20 >could be done [EE] >then it would be better! > >With kind regards, >Mario --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .