ref to analog apps journal for bubba oscillator

mybib.bib

@@ -32,7 +32,12 @@
 	keywords = "single-fault",
 	keywords = "fault-tolerance"
 }
-
+@ARTICLE{bubba,
+  AUTHOR =       "Ron Mancini",
+  TITLE =        "Design of OP-Amp sine wave oscillators",
+  JOURNAL =      "Analog Applications Journal: Texas Instruments: August",
+  YEAR =         "2000"
+}
 @ARTICLE{ftahistory,
   AUTHOR =       "Clifton Ericsson",
   TITLE =        "Fault Tree Analysis a History",

opamp_circuits_C_GARRETT/opamps.tex

@@ -494,7 +494,7 @@ The circuit in figure~\ref{fig:circuit2} shows a five pole low pass filter.
 Starting at the input, we have a first order low pass filter buffered by an op-amp, 
 the output of this is passed to a Sallen~Key~\cite{aoe}[p.267] second order lowpass filter.
 The output of this is passed into another Sallen~Key filter -- which although it may have different values
-for its resistors/capacitors and thus have a different frequency response -- is idential from a failure mode perspective.
+for its resistors/capacitors and thus have a different frequency response -- is identical from a failure mode perspective.
 Thus we can analyse the first Sallen~Key low pass filter and re-use the results.
 
 
@@ -518,7 +518,7 @@ a more sophisticated low pass filter.
 %
 R10 and C10 act as a potential divider, with the crucial difference between a purely resistive potential divider being
 that the impedance of the capacitor is lower for higher frequencies.
-Thus higher frquencies are attenuated at the point that we
+Thus higher frequencies are attenuated at the point that we
 read its output signal. 
 However, from a failure mode perspective we can analyse it in a very similar way
 to a potential divider (see section~\ref{potdivfmmd}).
@@ -728,10 +728,6 @@ We represent the desired FMMD hierarchy in figure~\ref{fig:circuit2h}.
 \label{tbl:fivepole}
 \end{table}
 
-
-
-
-
 We now can create a {\dc} to represent the circuit in figure~\ref{fig:circuit2}, we can call it
 $FivePoleLP$ and applying the $fm$ function to it (see table~\ref{tbl:fivepole}) yields $fm(FivePoleLP) = \{ HIGH, LOW,  FilterIncorrect,  NO\_SIGNAL \}$.
 
@@ -746,20 +742,6 @@ could be easily detected; the failure symptom $FilterIncorrect$  may be less obs
 
 
 
-
-
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-
-
-
-
-
-
-
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-
-
-
 \clearpage
 \section{Op-Amp circuit 3}
 
@@ -774,15 +756,17 @@ could be easily detected; the failure symptom $FilterIncorrect$  may be less obs
 %\clearpage
 %\section{Standard Non-inverting OP AMP}
 
-This circuit is described in the Analog Applications Journal~\cite{bubba}.
+This circuit is described in the Analog Applications Journal~\cite{bubba}[p.37].
 The circuit uses four 45 degree phase shifts, and an inverting amplifier to provide
 gain and the final 180 degrees of phase shift (making a total of 360 degrees of phase shift).
 
 From a fault finding perspective this circuit is less than ideal.
 The signal path is circular (its a positive feedback circuit) and most failures would simply cause the output to stop oscillating.
+The top level failure modes for the FMMD hierarchy bear this out.
 However, FMMD is a bottom -up analysis methodology and we can therefore still identify
 {\fgs} and apply analysis from a failure mode perspective.
 
+
 If we were to analyse this circuit without modularisation, we have 14 components with
 ($4.4 +10.2 = 36$) failure modes . Applying equation~\ref{eqnrd2} gives a complexity comparison figure of $13.36=468$.
 The reduce the complexity required to analyse this circuit we apply FMMD and start by determining {\fgs}.
@@ -1316,8 +1300,8 @@ Rigorous FMEA (RFMEA).
 The computational order for RFMEA would be polynomial ($O(N^2.K)$) (where $K$ is the variable number of failure modes).
 
 This order may be acceptable in a computational environment: However, the choosing of {\fgs} and the analysis
-process are human activities. It can be seen that it is practically impossible to achieve 
-RFMEA for anything but trival systems.
+process are by-hand/human activities. It can be seen that it is practically impossible to achieve 
+RFMEA for anything but trivial systems.
 %
 % Next statement needs alot of justification
 %
@@ -1541,13 +1525,8 @@ For Functional Group 2 (FG2), let us map:
   FS6 & \mapsto & S5    
 \end{eqnarray*}
 
-This 
-
-
-
-
-AUOMATIC chack can reveal WHEN double checking no longer necessary 
-in the hierarchy to cover dub sum !!!!! YESSSS:wq
+This AUTOMATIC check can reveal WHEN double checking no longer necessary 
+in the hierarchy to cover dub sum !!!!! YESSSS
 
 % does not cover what weird side effect may occur though, but then the {\fg} was not modelled correctly in the first place...