note nothingmuch compute the derivative of the wave pattern, and then whenever it is, say, over the last 4 samples by average larger than say .25 then you probably have a candidate for a peak. Keep looking till it stops rising, then try to find something with a proportionate declination in the derivative function. <p> If the noise is random you can use something like [http://www.fourmilab.ch/random/|ent]. This way you can look at long sample window and decide if it's got any islands or not in it. <p> This can get false islands in, but is also more sensitive than <p> There are more complicated algorithms, like the dolby stuff but that's probably overkill. <p> <div class="pmsig"><div class="pmsig-205152"> -nuffin<br>zz zZ Z Z #!perl </div></div> 545901 545901