SIGNAL MONOTONICITY In general,signal functions are monotone nondecreasing S'>=0. S(x) X -00 0 +00 This means signal functions have an upper bound or saturation value.SIGNAL MONOTONICITY In general, signal functions are monotone nondecreasing S’>=0. This means signal functions have an upper bound or saturation value. S(x) x -∞ - 0 + +∞