h | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
n | 1 | 2~4 | 5~11 | 12~26 | 27~57 | 58~120 | 121~247 |
错误 | 无 | H1 | H2 | H3 | H4 | H5 | H6 | H7 | |
C1 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 1 | C1 = H1 + H3 + H5 + H7 = 0 |
C2 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | C2 = H2 + H3 + H6 + H7 = 0 |
C3 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | C3 = H4 + H5 + H6 + H7 = 0 |
则得出
C1 = H1 + H3 + H5 + H7 = a1 + x1 + x2 + x4 = 0
C2 = H2 + H3 + H6 + H7 = a2 + x1 + x3 + x4 = 0
C3 = H4 + H5 + H6 + H7 = a3 + x2 + x3 + x4 = 0
a1 + x1 + x2 + x4 = 0
a2 + x1 + x3 + x4 = 0
a3 + x2 + x3 + x4 = 0
a3 = x4 + x3 + x2
a2 = x4 + x3 + x1
a1 = x4 + x2 + x1
海明码(Hamming Code )编码的关键是使用多余的奇偶校验位来识别一位错误。
h | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
n | 1 | 2~4 | 5~11 | 12~26 | 27~57 | 58~120 | 121~247 |
错误 | 无 | H1 | H2 | H3 | H4 | H5 | H6 | H7 | |
C1 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 1 | C1 = H1 + H3 + H5 + H7 = 0 |
C2 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | C2 = H2 + H3 + H6 + H7 = 0 |
C3 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | C3 = H4 + H5 + H6 + H7 = 0 |
则得出
C1 = H1 + H3 + H5 + H7 = a1 + x1 + x2 + x4 = 0
C2 = H2 + H3 + H6 + H7 = a2 + x1 + x3 + x4 = 0
C3 = H4 + H5 + H6 + H7 = a3 + x2 + x3 + x4 = 0
a1 + x1 + x2 + x4 = 0
a2 + x1 + x3 + x4 = 0
a3 + x2 + x3 + x4 = 0
a3 = x4 + x3 + x2
a2 = x4 + x3 + x1
a1 = x4 + x2 + x1
海明码(Hamming Code )编码的关键是使用多余的奇偶校验位来识别一位错误。
错误 | 无 | H1 | H2 | H3 | H4 | H5 | H6 | H7 | |
C1 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 1 | C1 = H1 + H3 + H5 + H7 = 0 |
C2 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | C2 = H2 + H3 + H6 + H7 = 0 |
C3 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | C3 = H4 + H5 + H6 + H7 = 0 |
则得出
C1 = H1 + H3 + H5 + H7 = a1 + x1 + x2 + x4 = 0
C2 = H2 + H3 + H6 + H7 = a2 + x1 + x3 + x4 = 0
C3 = H4 + H5 + H6 + H7 = a3 + x2 + x3 + x4 = 0
a1 + x1 + x2 + x4 = 0
a2 + x1 + x3 + x4 = 0
a3 + x2 + x3 + x4 = 0
a3 = x4 + x3 + x2
a2 = x4 + x3 + x1
a1 = x4 + x2 + x1
海明码(Hamming Code )编码的关键是使用多余的奇偶校验位来识别一位错误。