This lecture delves into the frequency response of linear systems, focusing on the concepts of impulse response and Fourier transforms. The instructor begins by reviewing previous material on linear time-invariant (LTI) systems, emphasizing the importance of impulse response in characterizing system behavior. The discussion progresses to the relationship between time-domain and frequency-domain representations, illustrating how input signals are modified by the system's frequency response. The instructor explains the significance of amplitude and phase shifts introduced by the system, using examples to clarify these concepts. The lecture also covers the design of filters, particularly low-pass filters, and their impact on signal processing. The instructor highlights the challenges of implementing ideal filters and the necessity of approximations in practical applications. Throughout the lecture, the instructor engages with students, encouraging questions and clarifying complex ideas. The session concludes with a summary of key points and a preview of upcoming topics related to filter design and signal processing techniques.