A non-invasive Cochlear Microphonic measurement system

The Cochlear Microphonic is one of the electrical potentials generated by the ear in response to audible stimuli. It is very difficult to measure the CM non-invasively because it has a very small magnitude (less than 1 μV). A high Common Mode Rejection Ratio (CMRR) and very large bandwidth (5 Hz–20 kHz) biomedical amplifier system is presented to measure the signal. The system also uses a driven right leg circuit to increase the CMRR.