Tanh is a control-domain math block that outputs the hyperbolic tangent of its control input, an S-shaped curve that maps any input into the range -1 to +1. It works purely on control signals, mapping a single control input to a single control output, and has no adjustable parameters.
On every tick it evaluates the hyperbolic tangent of the current control value and writes the result to its control output. It runs once per engine tick, one sample-frame at a time, in keeping with WaveWarp's sample-per-sample engine.