Lecture
This lecture covers the application of differential amplification in electrocardiogram (ECG) and photoplethysmogram (PPG) circuits, focusing on the design principles, sources of interference, and the use of differential amplifiers to enhance signal quality. The instructor explains the challenges of working with the human body's impedance, the importance of common mode rejection in medical instrumentation, and the impact of imperfections in differential amplifiers. Various circuit configurations and their implications are discussed, including the use of infinite input impedance variants and operational amplifiers. The lecture concludes with a detailed analysis of common mode rejection techniques and the trade-offs between complexity, consumption, and signal quality.