_           _                 
 | |_ ___  __| |____  ___ _   _ 
 | __/ _ \/ _` |_  / / _ \ | | |
 | ||  __/ (_| |/ / |  __/ |_| |
  \__\___|\__,_/___(_)___|\__,_|

Plan for BioMA circuit notes

• Biopotential amplifier design overview

  • Bipolar lead (v1 - v2)
  • Common-mode input, v_cm = (v1 + v2) / 2
  • Differential mode input, v_diff = v1 - v2
  • v1 = v_cm + v_diff / 2, v2 = v_cm + v_diff / 2
  • desired output is v_out = v_ref + A_diff * v_diff
  • real output is more like v_out = A_diff * v_diff + A_cm * v_cm
  • CMRR = 20 log10 A_diff / A_cm

• BioSlam circuit overview

  • Design principles: One bipolar lead, complete electrical isolation, a single quad opamp, breadboard, single supply 5V from laptop USB.

• Ohm's law v = iR

• Voltage divider, relationship between Va, Vc and Vb

• Non-inverting opamp circuit, allows Va, Vb to determine Vc

• BioSlam circuit combines four non-inverting opamp circuits

• Ohm's law with impedances phasors

• Voltage divider with impedances, phasors

• Frequency response of BioSlam circuit