6 Appendix

Figure 6-1 shows the loop parameters for the standard non-inverting buffer amplifier from Figure 3-3 without resistor R_A. The feedback factor β and the THD + N gain are 0 dB. The loop gain $A_{OL} + \beta = A_{OL}$

The addition of R_A to the otherwise standard non-inverting buffer amplifier configuration alters the feedback factor or THD + N gain of the circuit. The closed-loop signal gain A_CL is unchanged, but the feedback available for error correction is reduced by a factor of $101 \frac{V}{V}$ , thus extending the resolution by $101 \frac{V}{V}$ or 40 dB. Figure 6-2 shows the loop parameters with the addition of resistor R_A. The feedback factor β is reduced by -40 dB and the THD + N gain is increased by +40 dB. The loop gain $A_{OL} + \beta$ is reduced by -40 dB.