maxraise maxdrop produces on outlet 0 a piecewise-linear nonrecurrent fading according to the flow of incoming messages. For example, if maxraise=2 and maxdrop=4, then with each new message an output is produced that is at most 2 more or 4 less than the previous output. non-linear temporal lowpass filter (piecewise-constant) it is named "lin" because it has an output similar to [line], though the input is much different.