PAM4 indicates pulse-amplitude modulation, with the “4” indicating four levels of pulse modulation. PAM4 eye diagram An eye diagram for a PAM4 signal is unusual, with three eye openings and four ...

Common digital modulation techniques include amplitude-shift keying (ASK), frequency-shift keying (FSK), and phase-shift keying (PSK). ASK is the simplest of these techniques, and is used for low ...