Why CMRR is measured in dB?
The differential gain Ad magnifies the difference between the two input voltages.
But the common mode gain Ac magnifies the common mode DC voltage between the two inputs.
The ratio of two gains is said to be as a common mode rejection ratio.
The value of the format is in dB..
What is the advantage of a high CMRR?
advantage differential mode a high CMRR is good because it defines the difference at the output of an amplified differential mode input to an amplifier common mode input. Unwanted signals that couple into the differential input, predominantly will result in an unwanted common mode signal at the input.
What is a good CMRR?
The cheap mixers, with active balanced inputs and no transformers, could do around -70 dB CMRR at low frequencies. Minus 70 CMRR might be fine for a rock band on the road or small night club mixer, but you probably would want better performance if you’re going to record or broadcast something.
What is meant by CMRR?
The op amp common-mode rejection ratio (CMRR) is the ratio of the common-mode gain to differential-mode gain. For example, if a differential input change of Y volts produces a change of 1 V at the output, and a common-mode change of X volts produces a similar change of 1 V, then the CMRR is X/Y.