common mode rejection ratio的意思|示意

Common mode rejection ratio (CMRR) is an important indicator of the performance of an operational amplifier. It measures the ratio of the amplifier's differential gain (A) and common mode gain (Acm) under open loop conditions.

In an operational amplifier, CMRR is the ability to reject common mode input signals while maintaining a relatively high differential gain. Specifically, it is the ratio of the differential gain A to the common mode gain Acm. CMRR is usually expressed in decibels (dB), with higher numbers being better.

The most common application of CMRR is in instrumentation amplifiers, where it is used to separate the desired differential signals from common mode signals. The CMRR of an instrumentation amplifier should be as high as possible to minimize the effect of common mode noise on the desired differential signals.

The CMRR of an operational amplifier can be improved in several ways. First, proper component selection and design are important in order to minimize the common mode gain. It is also important to make sure that the physical layout of the amplifier is optimized in order to reduce parasitic capacitances and inductances. Finally, it is important to use high quality power supply filtering to reduce the effects of power supply noise on the amplifier.

In conclusion, CMRR is an important performance indicator of an operational amplifier. It is important to understand how to maximize the CMRR of an amplifier in order to optimize the performance of the amplifier.