A repetition code is very inefficient, and can be susceptible to problems if the error occurs in exactly the same place for each group (e.g., "1010 1010 1010" in the previous example would be detected as correct).
重复编码非常低效，并且如果错误在每个组的完全相同的地方发生，则很容易出现问题（例如上例中正巧错误为“1010 1010 1010”，将被检测为传输无误）。