Overshoot
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The term overshoot has the following meanings:
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[edit] Aviation
In aviation, an overshoot is an aborted landing. See: Go-around and Runway safety area.
[edit] Communication
In microwave communication, overshoot refers to reception of microwave signals where they are not intended as a result of an unusual atmospheric, e.g., ionospheric, conditions.
Source: from Federal Standard 1037C and from MIL-STD-188
[edit] Control theory
In control theory, overshoot refers to an output exceeding its final, steady-state value.[1] For a step input, the percentage overshoot (PO) is the maximum value minus the step value divided by the step value. In the case of the unit step, the overshoot is just the maximum value of the step response minus one.
[edit] Ecology
In ecology, overshoot occurs when a population exceeds the long term carrying capacity of its environment. The consequence of overshoot is called a crash or die-off. For a classic application of this concept to human experience, see Catton.[2]
[edit] Economics
In economics, overshoot may refer to the overshooting model for the volatility of exchange rates.
[edit] Electronics
In electronics, overshoot refers to the transitory values of any parameter that exceeds its final (steady state) value during its transition from one value to another. An important application of the term is to the output signal of an amplifier.[3]
Usage: Overshoot occurs when the transitory values exceed final value. When they are lower than the final value, the phenomenon is called "undershoot" or "negative overshoot".
A circuit is designed to minimize risetime while containing distortion of the signal within acceptable limits.
- Overshoot represents a distortion of the signal.
- In circuit design, the goals of minimizing overshoot and of decreasing circuit risetime can conflict.
- The magnitude of overshoot depends on time through a phenomenon called "damping." See illustration under step response.
- Overshoot often is associated with settling time, how long it takes for the output to reach steady state; see step response.
[edit] Mathematical approximation
In the approximation of functions, overshoot is one term describing quality of approximation. When a function such as a square wave is represented by a summation of terms, for example, a Fourier series or an expansion in orthogonal polynomials, the approximation of the function by a truncated number of terms in the series can exhibit overshoot, undershoot and ringing. The more terms retained in the series, the less pronounced the departure of the approximation from the function it represents. However, though the period of the oscillations decreases, their amplitude does not.[4] See Gibbs phenomenon.
[edit] References and notes
- ^ Kuo, Benjamin C & Golnaraghi M F (2003). Automatic control systems, Eighth edition, NY: Wiley, §7.3 p. 236-237. ISBN 0471134767.
- ^ William R. Catton (1980). Overshoot: the ecological basis of revolutionary change.. Urbana: University of Illinois Press, p. 278. ISBN 0252009886.
- ^ Phillip E Allen & Holberg D R (2002). CMOS analog circuit design, Second edition, NY: Oxford University Press, Appendix C2, p. 771. ISBN 0-19-511644-5.
- ^ Gerald B Folland (1992). Fourier analysis and its application. Pacific Grove, Calif.: Wadsworth: Brooks/Cole, pp. 60-61. ISBN 0-534-17094-3.
