1. The problem statement, all variables and given/known data I have an op amp with two electrode inputs. Each input has 5V of common 60 Hz noise. The size of the signal I want to measure is 9 mV. Signal to noise ratio needs to be 10 to 1. 2. Relevant equations I know that CMRR = 20 log (DMG/CMG), where DMG is differential mode gain and CMG is common mode gain. SNR = range of signal/range of noise 3. The attempt at a solution I know that CMG is equal to the ratio of Vout to Vcommon. Is Vcommon 10 V since I have two 5V inputs? Or would it be the average (5V)? How do I get Vout???? Where does the frequency come into play? Also, SNR = 10 and range/size of signal is 9 mV = .009 V, so range of noise = .0009 V. What is the equation for DMG? Can anyone direct me to a good internet reference that explains these ideas? The class I am in does not use a textbook. Thanks!