Ads
related to: observability and controllability testsdynatrace.com has been visited by 10K+ users in the past month
Search results
Results From The WOW.Com Content Network
Controllability and observability are dual aspects of the same problem. Roughly, the concept of controllability denotes the ability to move a system around in its entire configuration space using only certain admissible manipulations. The exact definition varies slightly within the framework or the type of models applied.
Observability is a measure of how well internal states of a system can be inferred from knowledge of its external outputs. In control theory, the observability and controllability of a linear system are mathematical duals. The concept of observability was introduced by the Hungarian-American engineer Rudolf E. Kálmán for linear dynamic systems.
However, a different input that attempts to set the signal to 0 will show a large increase in quiescent current, signalling a bad part. Typical Iddq tests may use 20 or so inputs. Note that Iddq test inputs require only controllability, and not observability. This is because the observability is through the shared power supply connection.
Controllability and observability are main issues in the analysis of a system before deciding the best control strategy to be applied, or whether it is even possible to control or stabilize the system. Controllability is related to the possibility of forcing the system into a particular state by using an appropriate control signal.
A special case of this result appeared first in 1963 in a paper by Elmer G. Gilbert, [1] and was later expanded to the current PBH test with contributions by Vasile M. Popov in 1966, [3] [4] Vitold Belevitch in 1968, [5] and Malo Hautus in 1969, [5] who emphasized its applicability in proving results for linear time-invariant systems.
While controllability and observability improvements for internal circuit elements definitely are important for test, they are not the only type of DFT. Other guidelines, for example, deal with the electromechanical characteristics of the interface between the product under test and the test equipment.
Controllability: The degree to which it is possible to control the state of the component under test (CUT) as required for testing. Observability: The degree to which it is possible to observe (intermediate and final) test results. Isolateability: The degree to which the component under test (CUT) can be tested in isolation.
In control theory, we may need to find out whether or not a system such as ˙ = + () = + is controllable, where , , and are, respectively, , , and matrices for a system with inputs, state variables and outputs.
Ads
related to: observability and controllability tests