“…However, the design process limits the speed of receivers. In conventional analog design, three comparators can be used to decode a PAM4 signal [13,14,15,16,17,18,19,20,21,22,23,24] by transforming it via three threshold voltages into a 3-digit thermometer code. These receivers are almost realized by analog circuit, excluding the threshold and DFE adaptation logics, and can reach very high speed.…”