Fig.1: NRZ signal (top) and eye diagram (bottom). Pulse amplitude modulation builds upon this concept by encoding data across multiple voltage levels. PAM4 uses four levels. A PAM4 signal can appear ...

This is the first time we've observed a circadian clock using pulse amplitude modulation, a concept typically associated with communication technology, to control biological functions." ...

Pulse amplitude modulation (PAM) is a way to pack more bits into the same amount of time on a serial channel. The usual mechanism used in serial communications is the binary non-return to zero (NRZ).