DIFFERENTIAL AMPLIFIER AND ELECTRODE FOR MEASURING A BIOPOTENTIAL

摘要

A differential amplifier is described that provides a high common mode rejection ration (CMRR) without requiring the use of precisely matched components. One variation employs a method of noise reduction to increase the SNR of the device. The differential amplifier may be used in an apparatus for measuring biopotentials of a patient, such as an electrode for measuring brain activity. The electrodes can communicate the measured biopotentials with a remote system for further processing, while providing electrical isolation to the patient.

主权项

1. An apparatus for measuring potentials on a body surface comprising:
a first contact area for contacting the body surface and providing a first signal; a second contact area for contacting the body surface and providing a second signal; a differential amplifier for providing an output signal proportional to the difference between the first signal and the second signal, the differential amplifier comprising:
a first OP-AMP having a first input, second input and an output, the first input coupled to the first signal and the second input coupled to the output;a second OP-AMP having a first input, second input and an output, the first input coupled to the second signal and the second input coupled to the output; anda resistor connected between the output of the first OP-AMP and the output of the second OP-AMP,wherein the output signal is proportional to the current through the resistor.