ArcTan2 (a,b) is a control-math block that computes the four-quadrant inverse tangent, atan2, of its two control inputs. There is no audio path — two control inputs (a and b) and one control output. It has no adjustable parameters.
Each tick it takes the two control values and outputs atan2(a, b), the angle in radians whose tangent is a/b resolved into the correct quadrant. It processes one sample-frame per tick, in step with WaveWarp's sample-per-sample engine.