A decoder includes a demultiplexer and a number (P) of ADCs, where P2. The demultiplexer receives a to-be-decoded data signal that is in a PAM-2M format, and demultiplexes the to-be decoded data signal into a number (P) of demultiplexed data signals, where M2. The ADCs respectively receive the demultiplexed data signals. One of the ADCs is an (M+1)-bit ADC, and converts the corresponding demultiplexed data signal into a digital first decoded signal that contains an M-bits wide data portion and a one-bit wide error portion. Each of the other one(s) of the ADCs is an M-bit ADC, and converts the corresponding demultiplexed data signal into a digital second decoded signal that contains an M-bits wide data portion. |