The heart and the ECG -- Right Leg Drive

A project log for Heartbeat Logger

A portable device that logs a snippet of your heart at the push of a button.

Ole Andreas UtstumoOle Andreas Utstumo 01/07/2016 at 10:010 Comments

Common mode noise and common mode noise converted to differential noise because of differences in input impedances as described in Signals and noise can be fought with a RLD - Right Leg Drive. The RLD is essentially sensing the common mode signal and drives an amplified inversion of it back into the body, usually as the name implies, into the right leg. This improves the common mode rejection of the ECG circuit by a factor of (1 + A), where A is the gain of the feedback loop.