Before proceeding into the specifics of the electronics, this slide shows the block diagram of the entire system involved starting with the protection circuitry on the front end. That is where the right arm, the left arm, the left leg are input through a lead selection scheme which is going to be differentially sensed by an instrumentation amp and then high pass filtered, amplified, low pass filtered, digitized with an analog digital converter, and communicated to the microcontroller at which point signal processing is going to occur.