Feedback and Stability: Active Filters

This lecture covers the topics of feedback and stability in amplifiers, focusing on different types of feedback-amplifier structures and the stability problem. It then transitions to the introduction of active filters, discussing filter fundamentals, types, and specifications. The systematic analysis of feedback voltage amplifiers is presented, including examples of inverting amplifiers and ideal feedback structures. The stability problem in feedback amplifiers is explored, emphasizing the transfer function, gain margin, and phase margin. The effect of phase margin on closed-loop response is discussed, along with alternative approaches for investigating stability. The lecture concludes with a summary of key concepts and the history of analog filters, leading to the introduction of active-RC and OTA-C filters.