A CMRR enhancement circuit by employing auxiliary buffer of capacitively coupled instrumentation amplifier for neural signal recording

Abstract

Here, a common-mode rejection ratio (CMRR) enhancement circuit is proposed by employing an auxiliary buffer (AB) to the pseudo resistors of the capacitively coupled instrumentation amplifier (CCIA). After applying AB to CCIA, the differential-mode gain remains the same with an extended bandwidth, and the common-mode gain is reduced, and therefore, the CMRR is enhanced.