In decision theory, the mathematical representation of a physical system which operates upon the observed data to produce a decision.
Related Terms 
GEARBOXA system of gears which alter the ratio between the revolution of the engine and the propeller shaft so the propeller operates in a relatively efficient speed range. By using a gearbox the engine and the propeller shaft will revolve at different speeds. 
DISTORTION

DEAD TIME

POLEPOSITIONING
A design technique used in linear control theory in which many or all of a system's closedloop poles are positioned as required, by proper choice of a linear state feedback law; if the system is controllable, all of the closedloop poles can be arbitrarily positioned by this technique.

PNEUMATIC WEIGHING SYSTEM
A system for weight measurement in which the load is detected by a nozzle and balanced by modulating the air pressure in an opposing capsule.

PLENUM SYSTEM
A heating or air conditioning system in which air is forced through a plenum chamber for distribution to ducts.

PLANT DECOMPOSITION
The partitioning of a largescale control system into subsystems along lines of weak interaction.

PIECEWISE LINEAR SYSTEM
A system for which one can divide the range of values of input quantities into a finite number of intervals such that the output quantity is a linear function of the input quantity within each of these intervals.

PHOTOELECTRICLOOPCONTROL
[CONTSYS] Aphotoelectric control system used as a position regulator for a loop of material passing from one stripprocessing line to another that may travel at a different speed. Also known as loop control.

PHOTOELECTRIC SORTER
A photoelectric control system used to sort objects according to color, size, shape, or other lightchanging characteristics.
