In order to ensure good quality of signal transmission, high speed serial data signal before transmission corresponding coding processing, often need to be shown in the figure 1 below is the simple serial signal transmission process, the sender signal Scrambler and first 8 b / 10 b encoding process, after processing the signal after transmission link transmission into the receiver is needed after 10 b / 8 b and Scrambler decoding process. All the signals we observe need to be observed on the transmission link, so what we observe is the encoded interference signal and 10b signal. The 8b/10b encoding is a very common encoding method used by most high-speed serial signals.For example, SATA and PCIE gen1/2 all use 8b/10b encoding.Using 8b/10b coding can ensure the DC balance of the circuit (keeping the density of 0 level and 1 level in balance), so that the system can recover the ideal clock from the data more accurately, and effectively reduce the inter-symbol interference jitter, so as to reduce the probability of system error as much as possible. In addition, 8 bits usually represent one data bit. If all the bits are used to represent data, there will be no extra bits to synchronize the code type. Therefore, another advantage of 8b/10b coding is to provide extra bits for synchronization code, such as the common K28.5 and K28.3 code types.