Answer:
80.9 db.
Explanation:
So, in this particular Question/problem we need to determine/calculate for the the worst possible CMRR. The data or information provided by the Question above;
=> ''amp differential amplifier is built using four identical resistors''
Therefore, R1 = R2 = R3 = R4. From the question above, we also know that the tolerance is ±5% for resistor that is;
A1 = A2 = A3 = A4 = A ±5%.
Using the kirchoff formula to each case, we have;
(1). Non Inverting terminal:
[ J - J2 / (A1 = A3) ] + J/ (A2 = A4) = 0.
J = 0.53 J2.
(2). Inverting terminal:
[ J_ - J2 / (A1 = A3) ] + J_ - Jb / (A2 = A4) = 0.
Thus, Jb = 2.11 J_ - 1.11 J2.
Note that J = J_ = 0.53 J2.
Thus, Jb = 1.11 J2 - 1.11 J1.
(Note that we will have that A2 = A4 = A + 0.05 = 1.05A.
Also, A1 = A3 = A - 0.05 = 0.95A).
The voltage is c1 and c2.
Therefore, Jb = 1.11( ccm + cv/2) - 1.11 ( Ccm - cv/2).
= - 10^-4 ccm - 1.11 cv.
Thus, CMMR = 20 log [| 1.11 ÷ (- 10^-4)|] = 80.9 db.
