"Simplified Noise Model"
Simplified Noise Model
Equivalent Resistance for noisy feedback:
\begin{equation}
R_{fn}=\frac{0.5 R_{a} \left(R_{b} - R_{s}\right)^{2}}{\left(R_{a} + R_{b} + R_{c}\right)^{2}} + \frac{R_{b} \left(R_{a} + R_{c} + R_{s}\right)^{2}}{\left(R_{a} + R_{b} + R_{c}\right)^{2}} + \frac{0.5 R_{c} \left(R_{b} - R_{s}\right)^{2}}{\left(R_{a} + R_{b} + R_{c}\right)^{2}}
\end{equation}
\begin{equation}
R_{fn}=56.55
\end{equation}
\begin{equation}
A=1.414 \left(\frac{\left(R_{a} + 0.5 R_{b} + R_{c} + 0.5 R_{s}\right)^{2}}{\left(R_{a} + R_{b} + R_{c}\right)^{2}}\right)^{0.5}
\end{equation}
\begin{equation}
D=1.414 \left(\frac{\left(0.5 R_{a} R_{b} + 0.5 R_{a} R_{s} + 0.5 R_{b} R_{c} + R_{b} R_{s} + 0.5 R_{c} R_{s}\right)^{2}}{\left(R_{a} + R_{b} + R_{c}\right)^{2}}\right)^{0.5}
\end{equation}
\begin{equation}
A=1.594
\end{equation}
\begin{equation}
D=223.7
\end{equation}