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submission_thesis/CH5_Examples/copy.tex
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@ -29,7 +29,7 @@ a variety of typical embedded system components including analogue/digital and e
The first section
~\ref{sec:determine_fms} looks at how we determine failure mode sets for {\bcs}
(in the context of the safety standards
we are conforming to for our particular project).
we are using for our particular project).
%
This is followed by several example FMMD analyses,
the first analysing a common configuration of
@ -50,13 +50,13 @@ where its re-use is appropriate in the first stage and
not in the second.
%
Section~\ref{sec:fivepolelp} analyses a Sallen-Key based five pole low pass filter.
This demonstrates FMMD being able to re-use the first Sallen-Key encountered as a {\dc}, thus
saving time and effort for the analyst.
This demonstrates FMMD being able to re-use the first Sallen-Key analysis, %encountered as a {\dc}
thus saving time and effort for the analyst.
%
Section~\ref{sec:bubba} shows FMMD applied to a circular circuit topology---the `Bubba' oscillator---which uses
four op-amp stages with supporting components.
%
Section~\ref{sec:sigmadelta} shows FMMD analysing the sigma delta analogue to digital converter---which operates on both
Section~\ref{sec:sigmadelta} shows FMMD analysing the sigma delta analogue to digital converter---again with a circular signal path---but which also operates on both
analogue and digital signals.
%
% Moving Pt100 to metrics
@ -293,7 +293,7 @@ $$ fm(R) = \{ OPEN, SHORT \} . $$
\centering
\includegraphics[width=200pt]{CH5_Examples/lm258pinout.jpg}
% lm258pinout.jpg: 478x348 pixel, 96dpi, 12.65x9.21 cm, bb=0 0 359 261
\caption{Pinout for an LM358 dual OP-AMP}
\caption{Pinout for an LM358 dual OpAmp}
\label{fig:lm258}
\end{figure}
@ -305,10 +305,10 @@ For the purpose of example, we look at
a typical op-amp designed for instrumentation and measurement, the dual packaged version of the LM358~\cite{lm358}
(see figure~\ref{fig:lm258}), and use this to compare the failure mode derivations from FMD-91 and EN298.
\paragraph{ Failure Modes of an OP-AMP according to FMD-91 }
\paragraph{ Failure Modes of an OpAmp according to FMD-91 }
%Literature suggests, latch up, latch down and oscillation.
For OP-AMP failures modes, FMD-91\cite{fmd91}{3-116] states,
For OpAmp failures modes, FMD-91\cite{fmd91}{3-116] states,
\begin{itemize}
\item Degraded Output 50\% Low Slew rate - poor die attach
\item No Operation - overstress 31.3\%
@ -318,11 +318,11 @@ For OP-AMP failures modes, FMD-91\cite{fmd91}{3-116] states,
Again these are mostly internal causes of failure, more of interest to the component manufacturer
than a designer looking for the symptoms of failure.
We need to translate these failure causes within the OP-AMP into {\fms}.
We need to translate these failure causes within the OpAmp into {\fms}.
We can look at each failure cause in turn, and map it to potential {\fms} suitable for use in FMEA
investigations.
\paragraph{OP-AMP failure cause: Poor Die attach}
\paragraph{OpAmp failure cause: Poor Die attach}
The symptom for this is given as a low slew rate. This means that the op-amp
will not react quickly to changes on its input terminals.
This is a failure symptom that may not be of concern in a slow responding system like an
@ -343,18 +343,18 @@ We map this failure cause to $HIGH$ or $LOW$.
\paragraph{Open $V_+$}
This failure cause will mean that the minus input will have the very high gain
of the OP-AMP applied to it, and the output will be forced HIGH or LOW.
of the OpAmp applied to it, and the output will be forced HIGH or LOW.
We map this failure cause to $HIGH$ or $LOW$.
\paragraph{Collecting OP-AMP failure modes from FMD-91}
We can define an OP-AMP, under FMD-91 definitions to have the following {\fms}.
\paragraph{Collecting OpAmp failure modes from FMD-91}
We can define an OpAmp, under FMD-91 definitions to have the following {\fms}.
\begin{equation}
\label{eqn:opampfms}
fm(OP-AMP) = \{ HIGH, LOW, NOOP, LOW_{slew} \}
fm(OpAmp) = \{ HIGH, LOW, NOOP, LOW_{slew} \}
\end{equation}
\paragraph{Failure Modes of an OP-AMP according to EN298}
\paragraph{Failure Modes of an OpAmp according to EN298}
EN298 does not specifically define OP\_AMPS failure modes; these can be determined
by following a procedure for `integrated~circuits' outlined in
@ -434,7 +434,7 @@ that we got from FMD-91, listed in equation~\ref{eqn:opampfms}.
%\clearpage
\subsubsection{Failure modes of an OP-AMP}
\subsubsection{Failure modes of an OpAmp}
\label{sec:opamp_fms}
For the purpose of the examples to follow, the op-amp will
@ -450,7 +450,7 @@ The EN298 pinouts failure mode technique cannot reveal failure modes due to inte
The FMD-91 entries for op-amps are not directly usable as
component {\fms} in FMEA or FMMD and require interpretation.
%For our OP-AMP example could have come up with different symptoms for both sides. Cannot predict the effect of internal errors, for instance ($LOW_{slew}$)
%For our OpAmp example could have come up with different symptoms for both sides. Cannot predict the effect of internal errors, for instance ($LOW_{slew}$)
%is missing from the EN298 failure modes set.
@ -661,7 +661,7 @@ If we consider the input will only be positive, we can invert the potential divi
We can form a {\dc} from this, and call it an inverted potential divider $INVPD$.
We can now form a {\fg} from the OP-AMP and the $INVPD$
We can now form a {\fg} from the OpAmp and the $INVPD$
\begin{table}[h+]
\caption{Inverting Amplifier: Single failure analysis}
@ -792,7 +792,7 @@ We can now form a {\fg} from the OP-AMP and the $INVPD$
$$ fm(INVAMP) = \{ {lowpass}, {high}, {low} \}.$$
\subsection{Second Approach: Inverting OP-AMP analysing with three components in one larger {\fg}}
\subsection{Second Approach: Inverting OpAmp analysing with three components in one larger {\fg}}
Here we analyse the same problem without using an intermediate $PD$
derived component.
@ -1275,7 +1275,7 @@ The op-amp IC1 is being used simply as a buffer. By placing it between the next
on the signal path, we remove the possibility of unwanted signal feedback.
The buffer is one of the simplest op-amp configurations.
It has no other components, and so we can now form a {\fg}
from the $FirstOrderLP$ and the OP-AMP component.
from the $FirstOrderLP$ and the OpAmp component.
\begin{table}[ht]
\caption{First Stage LP1: Failure Mode Effects Analysis: Single Faults} % title of Table
@ -1937,7 +1937,7 @@ there are more {\dcs} and this increases the possibility of re-use.
\section{Sigma Delta Analogue to Digital Converter ($\Sigma \Delta ADC$).} %($\Sigma \Delta ADC$)}
\section{Sigma Delta Analogue to Digital Converter (\sd).} %($\Sigma \Delta ADC$)}
\label{sec:sigmadelta}
The following example is used to demonstrate FMMD analysis of a mixed analogue and digital circuit (see figure~\ref{fig:sigmadelta}).
\begin{figure}[h]
@ -1956,7 +1956,7 @@ The following example is used to demonstrate FMMD analysis of a mixed analogue a
\centering
\includegraphics[width=200pt,keepaspectratio=true]{./CH5_Examples/sigma_delta_block.png}
% sigma_delta_block.png: 828x367 pixel, 72dpi, 29.21x12.95 cm, bb=0 0 828 367
\caption{Electrical signal path Block diagram: $\Sigma \Delta ADC$} % Analogue to Digital Converter }
\caption{Electrical signal path Block diagram: \sd} % Analogue to Digital Converter }
\label{fig:sigmadeltablock}
\end{figure}
@ -1986,11 +1986,14 @@ and fed into the summing integrator completing the negative feedback loop.
\subsection{FMMD analysis of \sd }
The partslist for the \sd :
%The partslist for the \sd :
%
$$\{ IC1, IC2, IC3, IC4, R1, R2, R3, R4, C1 \} $$.
%$$\{ IC1, IC2, IC3, IC4, R1, R2, R3, R4, C1 \} $$.
%
IC1,2 and 3 are all Op-amps and we have failure modes from section~\ref{sec:opampfm}.
The parts for the \sd are a mixture of analogue (resistors, capacitors, OpAmps) and digital
(D type flip flop, and a digital clock). We examine the failure modes of all components in this circuit below.
%
IC1,2 and 3 are all OpAmps and we have failure modes from section~\ref{sec:opamp_fms}.
%
$$ fm(OPAMP) = \{ HIGH, LOW, NOOP, LOW\_SLEW \} $$
%
@ -2013,7 +2016,8 @@ $$ fm ( CLOCK ) = \{ STOPPED \} $$
\subsection{Identifying initial {\fgs}}
\subsubsection{Summing Junction Integrator (SUMJINT)}
We now need to choose {\fgs}. The signal path is circular, but we can start
We now need to choose {\fgs}. The most obvious way to find initial {\fgs} id
to follow the signal path. The signal path is circular, but we can start
with the input voltage, which is applied via $R2$, we term this voltage $V_{in}$.
%
The feedback voltage for the ADC is supplied via $R1$, we term this voltage as $V_{fb}$.
@ -2024,12 +2028,12 @@ This can be our first {\fg} and we analyse it in table~\ref{tbl:sumjint}.
%For the symptoms, we have to think in terms of the effect
%on its performance as a summing junction and not be
%distracted by the integrator formed by $C_1$ and $IC1$.
$$G^0_1 = \{R1, R2 \}$$
%
$$FG = \{R1, R2, IC1, C1 \}$$
\begin{table}[h+]
\center
\caption{ Summing Junction Integrator($SUMJINT$): Failure Mode Effects Analysis} % title of Table
\caption{Summing Junction Integrator($SUMJINT$): Failure Mode Effects Analysis} % title of Table
\label{tbl:sumjint}
\begin{tabular}{|| l | l | c | c | l ||} \hline
@ -2067,48 +2071,16 @@ $$G^0_1 = \{R1, R2 \}$$
% \end{table}
From the analysis in table~\ref{tbl:sumj} we collect symptoms.
We can create the derived component
$SUMJINT$.% which has the failure modes from collecting its symptoms.
From the analysis in table~\ref{tbl:sumjint} we collect symptoms.
We create the derived component
$SUMJINT$ and assign it the failure modes collected above.% which has the failure modes from collecting its symptoms.
We now state:
$$ fm(SUMJUINT) = \{ V_{in} DOM, V_{fb} DOM, NO\_INTEGRATION, HIGH, LOW \} .$$
$$ fm(SUMJUINT^1_0) = \{ V_{in} DOM, V_{fb} DOM, NO\_INTEGRATION, HIGH, LOW \} .$$
% \subsubsection{Buffered Integrator}
%
% Following the signal path, the next functional group is the integrator.
% %
% This integrator is formed by placing $C1$ in the negative feedback loop of $IC2$\cite{aoe}[p.222].
% The output of the integrator is fed into IC2, which acts as a buffer,
% %performing the function of
% isolating the integrator from any load on its output.
% These three components work together to form a buffered integrator,
% and nicely form a {\fg}.
%
% $$G^0_2 = \{IC1, C1, IC2\}.$$
%
% The buffered integrator is analysed in table~\ref{tbl:intg}.
%
%
% \begin{table}[h+]
% \center
% \caption{IC1,C1,IC2 Buffered Integrator: Failure Mode Effects Analysis} % title of Table
% \label{tbl:intg}
%
% \begin{tabular}{|| l | l | c | c | l ||} \hline
% \textbf{Failure Scenario} & & \textbf{failure result } & & \textbf{Symptom} \\
% & & & & \\
% \hline \hline
%
%
%
% From the analysis in table~\ref{tbl:intg}, we can now create a derived component
% $BFINT$ which has the failure modes from collecting symptoms from the analysis in table~\ref{tbl:intg}.
% We can state
%
% $$ fm (BFINT) = \{ HIGH, LOW, NO\_INTEGRATION , LOW\_SLEW \} $$
%
That is the failure modes of our new {\dc} $SUMJINT^1_0$ are $\{ V_{in} DOM, V_{fb} DOM, NO\_INTEGRATION, HIGH, LOW \} .$
\clearpage
\subsubsection{High Impedance Signal Buffer (HISB)}
@ -2123,7 +2095,11 @@ It therefore has the failure modes of an Op-amp.
\center
% \center
\caption{ High Impedance Signal Buffer (HISB) : Failure Mode Effects Analysis} % title of Table
\caption{ High Impedance Signal Buffer : Failure Mode Effects Analysis} % title of Table
This is an OpAmp in a signal buffer configuration.
As it is performing one particular function
we my consider it as a derived component, that of a High Impedance Signal Buffer (HISB).
\begin{tabular}{|| l | l | c | c | l ||} \hline
@ -2134,24 +2110,19 @@ It therefore has the failure modes of an Op-amp.
\hline\hline
FS5: $IC2$ $HIGH$ & & output perm. high & & HIGH \\
FS6: $IC2$ $LOW$ & & output perm. low & & LOW \\ \hline
FS7: $IC2$ $NOOP$ & & no current to output & & $NOOP$ \\
FS8: $IC2$ $LOW\_SLEW$ & & delay signal & & $LOW\_SLEW$ \\ \hline
FS1: $IC2$ $HIGH$ & & output perm. high & & HIGH \\
FS2: $IC2$ $LOW$ & & output perm. low & & LOW \\
FS3: $IC2$ $NOOP$ & & no current to output & & $NOOP$ \\
FS4: $IC2$ $LOW\_SLEW$ & & delay signal & & $LOW\_{SLEW}$ \\ \hline
% FS1: $IC2$ $HIGH$ & & output perm. high & & HIGH \\
% FS2: $IC2$ $LOW$ & & output perm. low & & LOW \\ \hline
% FS3: $IC2$ $NOOP$ & & no current drive & & LOW \\
% FS4: $IC2$ $LOW\_SLEW$ & & delayed signal & & LOW\_SLEW \\ \hline
% \hline
\end{tabular}
\end{table}
% \hline
%
% \end{tabular}
% \end{table}
We create the {\dc} $HISB^1_1$ and it failure mode may be stated as $fm(HISB^1_1) = \{HIGH, LOW, NOOP, LOW_{SLEW} \}$.
\subsubsection{Digital level to analogue level conversion ($DL2AL$).}
Digital level to analogue level conversion is performed by IC3 in conjunction with a potential divider formed by R3,R4.
@ -2161,27 +2132,27 @@ to the inverting input of IC3.
\paragraph{Potential divider Formed by R3,R4.}
We re-use the analysis from table~\ref{tbl:pdfmea}, and use the derived component $PD$
to represent the potential divider formed by R3 and R4. Because PD is a derived component, we can denote this
by super-scripting it with its abstraction level of 1, thus $PD^1$.
by super-scripting it with its abstraction level of 1, thus $PD$.
$$
fm(PD^1) = \{ HIGH, LOW \}.
fm(PD) = \{ HIGH, LOW \}.
$$
%
IC3 is an op-amp and has the failure modes
$$fm(IC3) = \{\{ HIGH, LOW, NOOP, LOW\_SLEW \} . $$
%
The digital signal is supplied to the non-inverting input.
The output is a voltage level in the analogue domain $-V$ or $+V$.
%
We now form a {\fg} from $PD $ and $IC3$.
%
$$ FG = \{ PD , IC3 \} $$
%
We now analyse the {\fg} $G $ in table~\ref{tbl:DS2AS}.
We now form a {\fg} from $PD^1$ and $IC3$.
$$ G^1_0 = \{ PD^1, IC3 \} $$
We now analyse the {\fg} $G^1$ in table~\ref{tbl:DS2AS}.
%$$ fm (BFINT) = \{ HIGH, LOW, NO\_INTEGRATION , LOW\_SLEW \} $$
\begin{table}[h+]
\center
\caption{$PD^1, IC3$ Digital level to analogue level converter: Failure Mode Effects Analysis} % title of Table
\caption{$PD , IC3$ Digital level to analogue level converter: Failure Mode Effects Analysis} % title of Table
\label{tbl:DS2AS}
\begin{tabular}{|| l | l | c | c | l ||} \hline
@ -2192,34 +2163,78 @@ We now analyse the {\fg} $G^1$ in table~\ref{tbl:DS2AS}.
\textbf{cause} & & \textbf{Effect} & & \textbf{Failure Mode} \\
\hline \hline
FS1: $PD^1$ $HIGH$ & & output perm. low & & LOW \\
FS2: $PD^1$ $LOW$ & & output perm. low & & HIGH \\ \hline
FS1: $PD $ $HIGH$ & & output perm. low & & LOW \\
FS2: $PD $ $LOW$ & & output perm. low & & HIGH \\ \hline
\hline
FS3: $IC3$ $HIGH$ & & output perm. high & & HIGH \\
FS4: $IC3$ $LOW$ & & output perm. low & & LOW \\ \hline
FS4: $IC3$ $LOW$ & & output perm. low & & LOW \\
FS5: $IC3$ $NOOP$ & & no current drive & & LOW \\
FS6: $IC3$ $LOW\_SLEW$ & & delayed signal & & LOW\_SLEW \\ \hline
FS6: $IC3$ $LOW\_{SLEW}$ & & delayed signal & & $LOW\_{SLEW}$ \\ \hline
\hline
\end{tabular}
\end{table}
We collect the symptoms of failure $\{ LOW, HIGH, LOW\_SLEW \}$.
We collect the symptoms of failure $\{ LOW, HIGH, LOW\_{SLEW} \}$.
We can now derive a new component to represent the level conversion and call it $DL2AL$.
$$ DL2AL^2 = D(G^1_0) $$
$$ DL2AL = D(FG = \{ PD , IC3 \}) $$
$$ fm (DL2AL^2) = \{ LOW, HIGH, LOW\_SLEW \} $$
$$ fm (DL2AL^2) = \{ LOW, HIGH, LOW\_{SLEW} \} $$
\clearpage
% \subsubsection{digital clocked memory (flip-flop).}
\subsubsection{$DIGBUF$ --- digital clocked memory (flip-flop).}
%
% This is a single component as a {\fg}, and we can state
% $$ fm (DCM) = \{ HIGH, LOW, NOOP \} $$
The digital element of the {\sd}, is the one bit memory, or D type flip flop. This
buffers the feedback result and provides the output bit stream.
We create a {\fg} from the CLOCK and IC4 to model this digital buffer.
$$FG = \{ IC4, CLOCK \}$$
%% DIGBUF --- Digital Buffer
We now analyse this {\fg} in table~\ref{tbl:digbuf}.
\begin{table}[h+]
\center
\caption{$ IC4, CLOCK $ Digital Buffer: Failure Mode Effects Analysis} % title of Table
\label{tbl:digbuf}
\begin{tabular}{|| l | l | c | c | l ||} \hline
%\textbf{Failure Scenario} & & \textbf{failure result } & & \textbf{Symptom} \\
% & & & & \\
% & & & & \\
\textbf{Failure} & & \textbf{$DIGBUF$ } & & \textbf{Derived Component} \\
\textbf{cause} & & \textbf{Effect} & & \textbf{Failure Mode} \\
%$$ fm ( CD4013B) = \{ HIGH, LOW, NOOP \} $$
\hline \hline
FS1: $CLOCK$ $STOPPED$ & & buffer stopped & & STOPPED \\ \hline
FS2: $IC4$ $HIGH$ & & buffer stopped & & STOPPED \\
FS3: $IC4$ $LOW$ & & buffer stopped & & STOPPED \\
FS4: $IC4$ $NOOP$ & & no current drive & & LOW \\ \hline
\hline
\hline
\end{tabular}
\end{table}
We collect the symptoms of failure $\{ LOW, STOPPED \}$.
We can now derive a new component to represent the level conversion and call it $DIGBUF$.
$$ fm (DIGBUF) = \{ LOW, STOPPED \} $$
%%% END DIGBUF
\subsection{First {\fgs} analysed}
@ -2234,12 +2249,14 @@ These are:
\item HISB --- A High impedance buffer,
\item DIGITALBUFF --- A one bit digital buffer,
\item DL2AL --- A digital to analog level converter.
\item DIGBUF --- A digital one bit buffer/memory
\end{itemize}
These {\dcs} follow to signal path shown in figure~\ref{fig:sigmadeltablock}.
We now use these {\dcs} to create a final {\fg} to represent the failure mode
behaviour of the $\Sigma \Delta ADC$. We represent this
in the Euler diagram in figure~\ref{fig:eulersd}.
The next stage is to create {\fgs} from these initial {\dcs}
and make a complete failure mode mode for the {\sd}.
\begin{figure}[h]
\centering
@ -2259,26 +2276,24 @@ in the Euler diagram in figure~\ref{fig:eulersd}.
% \end{figure}
IC4 is as yet unused, the signal path connects IC4 and DL2AL. These seem natural candidates
for the next {\fg}.
%IC4 is as yet unused, the signal path connects IC4 and DL2AL. These seem natural candidates
%for the next {\fg}.
BFINT and SUMJ are adjacent in the signal path and these are chosen as a {\fg} as well.
\clearpage
\subsubsection{{\fg} $BFINT^1$ and $SUMJ^1$}
\subsubsection{{\fg} $HISB$ and $SUMJINT$}
We now form a {\fg} with the two derived components $BFINT^1$ and $SUMJINT^1$.
We now form a {\fg} with the two derived components $HISB$ and $SUMJINT$.
This forms a buffered integrating summing junction which we analyse in table~\ref{tbl:BISJ}.
$$ G^1_0 = \{ BFINT^1, SUMJ^1 \} $$
$$ FG = \{ HISB, SUMJINT \} $$
%$$ fm (BFINT) = \{ HIGH, LOW, NO\_INTEGRATION , LOW\_SLEW \} $$
%$$ fm(SUMJ) = \{ V_{in} DOM, V_{fb} DOM \} .$$
\begin{table}[h+]
\caption{ $BFINT^1, SUMJ^1$ buffered integrating summing junction($BISJ$): Failure Mode Effects Analysis} % title of Table
\caption{ $HISB , SUMJINT$ buffered integrating summing junction($BISJ$): Failure Mode Effects Analysis} % title of Table
\label{tbl:DS2AS}
\begin{tabular}{|| l | l | c | c | l ||} \hline
@ -2290,14 +2305,17 @@ $$ G^1_0 = \{ BFINT^1, SUMJ^1 \} $$
\hline \hline
FS1: $SUMJ^1$ $V_{in} DOM$ & & output integral of $V_{in}$ & & $OUTPUT STUCK$ \\
FS2: $SUMJ^1$ $V_{fb} DOM$ & & output integral of $V_{fb}$ & & $OUTPUT STUCK$ \\ \hline
FS1: $SUMJINT$ $V_{in} DOM$ & & output integral of $V_{in}$ & & $OUTPUT STUCK$ \\
FS2: $SUMJINT$ $V_{fb} DOM$ & & output integral of $V_{fb}$ & & $OUTPUT STUCK$ \\
% $$ fm(SUMJUINT^1_0) = \{ V_{in} DOM, V_{fb} DOM, NO\_INTEGRATION, HIGH, LOW \} .$$
FS3: $SUMJINT$ $NO\_INTEGRATION$ & & output stuck high or low & & $OUTPUT STUCK$ \\
FS4: $SUMJINT$ $HIGH$ & & output stuck high & & $OUTPUT STUCK$ \\
FS5: $SUMJINT$ $LOW$ & & output stuck low & & $OUTPUT STUCK$ \\ \hline
%\hline
FS3: $BFINT^1$ $HIGH$ & & output perm. high & & $OUTPUT STUCK$ \\
FS4: $BFINT^1$ $LOW$ & & output perm. low & & $OUTPUT STUCK$ \\ \hline
FS5: $BFINT^1$ $ NO\_INTEGRATION$ & & no current drive & & $OUTPUT STUCK$ \\
FS6: $BFINT^1$ $LOW\_SLEW$ & & delayed signal & & $REDUCED\_INTEGRATION$ \\ \hline
FS6: $HISB$ $HIGH$ & & output perm. high & & $OUTPUT STUCK$ \\
FS7: $HISB$ $LOW$ & & output perm. low & & $OUTPUT STUCK$ \\
FS8: $HISB$ $ NO\_INTEGRATION$ & & no current drive & & $OUTPUT STUCK$ \\
FS9: $HISB$ $LOW\_SLEW$ & & delayed signal & & $REDUCED\_INTEGRATION$ \\ \hline
\hline
\end{tabular}
@ -2317,40 +2335,40 @@ called $BISJ^2$.
\subsubsection{{\fg} $IC4$ and $DL2AL$}
\subsubsection{{\fg} $DL2AL$ and $DIGBUF$}
%$$ fm (DL2AL^2) = \{ LOW, HIGH, LOW\_SLEW \} $$
%$$ fm ( CD4013B) = \{ HIGH, LOW, NOOP \} $$
The functional group formed by $IC4$ and $DL2AL$ takes the flip flop clocked and buffered
The functional group formed by $DIGBUF$ and $DL2AL$ takes the flip flop clocked and buffered
value, and outputs it at analogue voltage levels for the summing junction.
$ G^2_1 = \{ IC4^0, DL2AL^2, CLOCK\} $
$ FG = \{ DIGBUF, DL2AL \} $
We analyse the buffered flip flop circuitry in table~\ref{tbl:FFB}.
We analyse the buffered flip flop circuitry in table~\ref{tbl:digbuf}.
\begin{table}[h+]
\caption{ $IC4^0,DL2AL^2$ flip flop buffered($FFB$): Failure Mode Effects Analysis} % title of Table
\label{tbl:FFB}
\caption{ $DIGBUF,DL2AL$ flip flop buffered($FFB$): Failure Mode Effects Analysis} % title of Table
\label{tbl:digbuf}
\begin{tabular}{|| l | l | c | c | l ||} \hline
%\textbf{Failure Scenario} & & \textbf{failure result } & & \textbf{Symptom} \\
% & & & & \\
% & & & & \\
\textbf{Failure} & & \textbf{$FFB$ } & & \textbf{Derived Component} \\
\textbf{Failure} & & \textbf{$DIGBUF$ } & & \textbf{Derived Component} \\
\textbf{cause} & & \textbf{Effect} & & \textbf{Failure Mode} \\
\hline \hline
FS1: $IC4^0$ $HIGH$ & & output stuck high & & $OUTPUT STUCK$ \\
FS2: $IC4^0$ $LOW$ & & output stuck low & & $OUTPUT STUCK$ \\
FS3: $IC4^0$ $NOOP$ & & output stuck low & & $OUTPUT STUCK$ \\ \hline
FS1: $DIGBUF$ $STOPPED$ & & output stuck & & $OUTPUT STUCK$ \\
FS2: $DIGBUF$ $LOW$ & & output stuck low & & $OUTPUT STUCK$ \\
\\ \hline
%\hline
FS4: $DL2AL^2$ $LOW$ & & output perm. high & & $OUTPUT STUCK$ \\
FS5: $DL2AL^2$ $HIGH$ & & output perm. low & & $OUTPUT STUCK$ \\ \hline
FS6: $DL2AL^2$ $LOW\_SLEW$ & & no current drive & & $LOW\_SLEW$ \\
FS3: $DL2AL$ $LOW$ & & output perm. high & & $OUTPUT STUCK$ \\
FS4: $DL2AL$ $HIGH$ & & output perm. low & & $OUTPUT STUCK$ \\ \hline
FS5: $DL2AL$ $LOW\_SLEW$ & & no current drive & & $LOW\_SLEW$ \\
FS7: $CLOCK^0$ $STOPPED$ & & output stuck & & $OUTPUT STUCK$ \\
\hline
\hline
\end{tabular}
@ -2360,6 +2378,7 @@ We now collect symptoms $\{OUTPUT STUCK, LOW\_SLEW\}$ and create a {\dc} at the
called $FFB^3$.
\clearpage
\subsection{Final, top level {\fg} for sigma delta Converter}
@ -2402,13 +2421,13 @@ $$fm(SSDADC^4) = \{OUTPUT\_OUT\_OF\_RANGE, OUTPUT\_INCORRECT\}$$
We now show the final hierarchy in figure~\ref{fig:sdadc}.
\begin{figure}[h]
\centering
\includegraphics[width=400pt]{./CH5_Examples/sdadc.png}
% sdadc.png: 886x1134 pixel, 72dpi, 31.26x40.01 cm, bb=0 0 886 1134
\caption{FMMD Analysis hierarchy for the {\sd}}
\label{fig:sdadc}
\end{figure}
% \begin{figure}[h]
% \centering
% \includegraphics[width=400pt]{./CH5_Examples/sdadc.png}
% % sdadc.png: 886x1134 pixel, 72dpi, 31.26x40.01 cm, bb=0 0 886 1134
% \caption{FMMD Analysis hierarchy for the {\sd}}
% \label{fig:sdadc}
% \end{figure}
\clearpage
% ]

4
submission_thesis/style.tex
View File

@ -31,8 +31,8 @@
\newcommand{\permil}{\ensuremath{0/{\!}_{00}}}
%\newcommand{\emp}{ELECTRO MAGNETIC FUKING PULSE}
\newcommand{\emp}{} %% was italics
%\newcommand{\sd}{\ensuremath{\Sigma \Delta ADC}}
\newcommand{\sd}{\ensuremath{Sigma\;Delta\;ADC}}
\newcommand{\sd}{\ensuremath{\Sigma \Delta ADC}}
%\newcommand{\sd}{\ensuremath{Sigma\;Delta\;ADC}}
\newcommand{\derivec}{{D}}
\newcommand{\abslev}{\ensuremath{\alpha}}
\newcommand{\oc}{\ensuremath{^{o}{C}}}