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opamp_circuits_C_GARRETT/opamps.tex

@@ -486,6 +486,16 @@ wihen it becomes a V2 follower).
 \section{Basic Concepts Of FMMD}
 
 
+
+\paragraph {Definitions}
+
+\begin{itemize}
+\item {\bc} - a component with a known set of unitary state failure modes. Base here mean a starting or `bought~in' component. 
+\item {\fg} -  a collection of components chosen to perform a particular task
+\item {\em symptom} - a failure mode of a functional group caused by one or more of its component failure modes.
+\item {\dc} - a new component derived from an analysed {\fg}
+\end{itemize}
+
 \paragraph{ Creating a fault hierarchy.}
 The main concept of FMMD is to build a hierarchy of failure behaviour from the {\bc}
 level up to the top, or system level, with analysis stages between each 
@@ -506,19 +516,18 @@ we can determine its symptoms of failure.
 %In fact we can call these
 %the symptoms of failure for the {\fg}.
 
-With these Syptoms (a set of derived faults from the perspective of the {\fg})
-% and is thus at a higher level of 
-%fault~mode abstraction. 
-We can now say that the {\fg} (as an entity in its own right) can fail in a number of well defined ways.
-
+With these symptoms (a set of derived faults from the perspective of the {\fg}) 
+we can now state that the {\fg} (as an entity in its own right) can fail in a number of well defined ways.
+%
 In other words we have taken a {\fg}, and analysed how 
-it can fail according to the failure modes of its components.
+\textbf{it} can fail according to the failure modes of its components, and then
+determined the {\fg} failure modes.
 %These new failure~modes are derived failure modes.
 %The ways in which the module can fail now becomes a new set of fault modes, the fault~modes
 %being derived from the {\fg}.
 \paragraph{Creating a derived component.} 
-We can now create a new `{\dc}' which has
-the failure symptoms of the {\fg} as its set of failure modes.
+We create a new `{\dc}' which has
+the failure symptoms of the {\fg} from which it was derived, as its set of failure modes.
 This new {\dc} is at a higher `failure~mode~abstraction~level' than {\bcs}.
 %
 \paragraph{An example of a {\dc}.}
@@ -553,15 +562,6 @@ mode model of the system under investigation.
 
 
 
-\subsection { Definitions }
-
-\begin{itemize}
-\item {\bc} - a component with a known set of unitary state failure modes. Base here mean a starting or `bought~in' component. 
-\item {\fg} -  a collection of components chosen to perform a particular task
-\item {\em symptom} - a failure mode of a functional group caused by one or more of its component failure modes.
-\item {\dc} - a new component derived from an analysed {\fg}
-\end{itemize}
-
 \subsection{An algebraic notation for identifying FMMD enitities}
 Consider all `components' to exist as
 members of a set $\mathcal{C}$.
@@ -639,8 +639,9 @@ $$ \bowtie(FG^{\abslevel}) \rightarrow c^{{\abslevel}+N} | N \ge 1. $$
 The $\bowtie$ function processes each component in the {\fg} and 
 extracts all the component failure modes.
 With all the failure modes, an analyst can   
-determine the symptoms. A new {\dc} is created
-where its failure modes,  are the symptoms from $FG$.
+determine how each failure mode will affect the {\fg}, and then collect common symptoms.
+A new {\dc} is created
+where its failure modes,  are the symptoms from {\fg}.
 Note that the component must have a higher abstraction level than the {\fg}
 it was derived from.
 
@@ -651,7 +652,7 @@ We can stipulate that symptom collection process is surjective.
 By stipulating surjection for symptom collection, we ensure
 that each component failure mode maps to at least one one symptom.
 We also ensure that all symptoms have at least one component failure
-mode.
+mode (i.e. one or more failure modes that caused it).
 %
 
 \subsection{FMMD Hierarchy}