Coding: the sampled signal has great redundancy, but the large amount of data contains little information and needs special coding; Modulation: information cannot be transmitted directly, because its anti-interference ability and transmission ability are not good, so it should be placed on tolerable electromagnetic waves, which is modulation; Shaping: Due to the influence of interference and noise, the waveform of the received signal is distorted and needs to be shaped and restored. That's probably what it means, of course, there are some in-depth topics in it.