Multi-level pulse amplitude modulation (PAM) is a technique used in digital communication to transmit data by varying the amplitude of pulses. Unlike traditional binary pulse amplitude modulation, which uses two levels (0 and 1), multi-level PAM can represent multiple bits per symbol by using several amplitude levels. This allows for more efficient data transmission over a given bandwidth. In multi-level PAM, each amplitude level corresponds to a unique combination of bits. For example, 4-PAM uses four different amplitude levels to represent two bits of data. This increased capacity can improve data rates, but it also makes the system more susceptible to noise and distortion, requiring careful design and error correction methods.