From 6b18adfcc3cf8f06b4ab0267d8e3d437d5c775b2 Mon Sep 17 00:00:00 2001 From: "Robin P. Clark" Date: Tue, 17 Sep 2013 13:48:34 +0100 Subject: [PATCH] jag vill har nagra kul saker.... --- submission_thesis/CH5_Examples/copy.tex | 38 +++++++++++++++---------- 1 file changed, 23 insertions(+), 15 deletions(-) diff --git a/submission_thesis/CH5_Examples/copy.tex b/submission_thesis/CH5_Examples/copy.tex index 9b9385e..cdb6b99 100644 --- a/submission_thesis/CH5_Examples/copy.tex +++ b/submission_thesis/CH5_Examples/copy.tex @@ -22,7 +22,7 @@ this examines re-use of the potential divider {\dc} from section~\ref{subsec:pot This amplifier is analysed twice, using different compositions of {\fgs}. The two approaches, i.e. effects of choice of membership for {\fgs} are then discussed. %\ -fmmdglossOPAMP +\fmmdglossOPAMP \item Section~\ref{sec:diffamp} analyses a circuit where two op-amps are used to create a differencing amplifier. Building on the two approaches from section~\ref{sec:invamp}, re-use of the non-inverting amplifier {\dc} from section~\ref{sec:invamp} @@ -53,6 +53,11 @@ by analysing a sigma delta ADC. safety critical temperature sensor circuit, analysed for single and double failure mode scenarios. \end{itemize} + + + + + \clearpage \section{Example Analysis: Inverting OPAMP} % @@ -66,6 +71,19 @@ safety critical temperature sensor circuit, analysed for single and double failu \label{fig:invamp} \end{figure} % +Figure~\ref{fig:invamp} shows a standard configuration inverting amplifier. +A valid range for the output value of this circuit is assumed. +% +%Thus negative or low voltages can be considered as LOW +%and voltages higher than a given threshold considered as HIGH. +% +Because the amplifier inverts and the input is guaranteed positive any +output voltage above or equal to zero would be erroneous. +% +This would be an `$AMP_{HIGH}$' failure symptom. +% +A threshold would be determined for an `$AMP_{LOW}$' failure symptom (i.e. the output voltage more negative than expected). % error given the expected input range. +% %This configuration is interesting from methodology pers. There are two obvious ways in which this circuit can be modelled. % @@ -100,17 +118,6 @@ In normal operation then, this is an inverted potential divider. It must therefore be viewed as an inverted potential divider and analysed as such; see table~\ref{tbl:pdneg}. % -A valid range for the output value of this circuit is assumed. -% -%Thus negative or low voltages can be considered as LOW -%and voltages higher than a given threshold considered as HIGH. -% -Because the amplifier inverts and the input is guaranteed positive any -output voltage above or equal to zero would be erroneous. -% -This would be an $AMP_{HIGH}$ failure symptom. -% -A threshold would be determined for an $AMP_{LOW}$ failure symptom (i.e. the output voltage more negative than expected). % error given the expected input range. % \begin{table}[h+] \caption{Inverted Potential divider: Single failure analysis} @@ -199,6 +206,7 @@ by forming a {\fg} with the OpAmp and the new {\dc} $IPD$. \end{table} % % +\clearpage %%This gives the same results as the analysis from figure~\ref{fig:invampanalysis}. % % @@ -303,7 +311,7 @@ by forming a {\fg} with the OpAmp and the new {\dc} $IPD$. Failure modes for the {\dc} $INVAMP$ can be expressed thus; %% $$ fm(INVAMP) = \{ {lowpass}, {high}, {low} \}.$$ $$ fm(INVAMP) = \{ HIGH, LOW, LOW PASS \} .$$ - +% \clearpage A DAG is drawn representing the failure mode behaviour of this amplifier (see figure~\ref{fig:invdag1}). % @@ -311,8 +319,8 @@ Note that this allows failure symptoms to be traced back to causes, i.e. to traverse from system level or top failure modes to base component failure modes. %%%%% 12DEC 2012 UP to here in notes from AF email. % -\clearpage % +\clearpage \subsection{Second Approach: Inverting OpAmp analysing with three components in one larger {\fg}} \label{subsec:invamp2} @@ -368,7 +376,7 @@ This concern is re-visited in the differencing amplifier example in the next sec \label{tbl:invamp} \end{table} -\clearpage +%\clearpage \subsection{Comparison between the two approaches} \label{sec:invampcc}