Lecture
This lecture covers the concepts of signals, frequencies, and bandwidth, explaining that a signal is a function and providing examples such as sound waves, electromagnetic waves, black-and-white photos, color photos, and videos. It delves into the properties of pure sinusoids, discussing amplitude, frequency, and phase. The lecture also explores the representation of signals as a sum of sinusoids, emphasizing that any signal can be decomposed into sinusoidal components. Furthermore, it introduces the measurement unit of frequency, the hertz, and its significance in signal repetition. The lecture concludes by presenting some typical frequency ranges for sound waves, from audible sounds to ultrasonic frequencies.