#lang scribble/manual
@(require (for-label racket))

@title{(zero-crossing in)}


Zero crossing frequency follower.

outputs a frequency based upon the distance between interceptions
of the X axis. The X intercepts are determined via linear
interpolation so this gives better than just integer wavelength
resolution. This is a very crude pitch follower, but can be useful
in some situations.

in - input signal.


@racketblock[
(let* ((a (mul (sin-osc ar (mul-add (sin-osc kr 1 0) 600 700) 0) 0.1))
       (b (mul (impulse ar (zero-crossing a) 0) 0.25)))
  (audition (out 0 (mce2 a b))))
]