In the transition of any parameter from one value to another, the transitory value of the parameter that exceeds the final value. Note: Overshoot occurs when the transition is from a lower value to a higher value. When the transition is from a higher value to a lower value, and the parameter takes a transitory value that is lower than the final value, the phenomenon is called undershoot. 2. The increased amplitude of a portion of a nonsinusoidal waveform, i.e., signal, at the output of a nonlinear circuit, e. G. , a realizable amplifier, caused by the characteristics of the circuit. Note 1: Overshoot causes distortion of the signal. Note 2: Overshoot may result from circuit design parameters that are intended to decrease the response time of the circuit. Note 3: The amount of overshoot in a given circuit is designed to minimize response time while maintaining distortion of the signal within acceptable limits. The absence or presence of overshoot, and if present, its magnitude, is a function of a circuit design parameter called damping. 3. The result of an unusual atmospheric, e. G. , ionospheric, condition that causes microwave signals to be received where they are not intended.