A transmitter encoding apparatus includes a multiplexer and a first transmitter encoder. The multiplexer receives a first digital signal and a second signal and to generate an output, in which the output of the multiplexer includes M-bit code words of the first digital signal and M-bit code words of the second digital signal arranged in an interleaved manner. The first transmitter encoder receives the output of the multiplexer and generates N-bit code words, and N is not equal to M. The first transmitter encoder determines a current N-bit code word of the N-bit code words according to the output of the multiplexer and a disparity of a previous N-bit code word of the N-bit code words. The first transmitter encoder transmits the N-bit code words to a receiver decoding apparatus including a demultiplexer and a first receiver decoder configured to decode the N-bit code words.