Pulse Amplitude Modulation (PAM) is a technique used in signal processing where the amplitude of a series of pulses is varied to represent information. In PAM, each pulse corresponds to a sample of the original signal, and the height of the pulse indicates the value of that sample. This method is commonly used in digital communication systems to transmit data efficiently. PAM can be seen as a simpler form of modulation compared to other techniques like Pulse Width Modulation (PWM) or Pulse Position Modulation (PPM). It is often used in applications such as audio signal transmission and data communication, where the quality of the signal is important for accurate information retrieval.