I've attached some example code that generates a
saw wave (p), applies a
nonlinear function (x, p^2 * 0.3 + p^3 * 0.73 - p^5 * 0.1), a highpass
filter and a delay (about 16.1 samples), then puts the transfer function
into a table (ignoring the delay). It can guess the correct input/output
alignment by looking at the shape of the out-of-sync transfer function.
There is an example here:
http://plugin.org.uk/tmp/foo.png