| 摘要 |
PURPOSE:To correct an error of a memory cell and to save bit errors due to a fixed defective bit, alpha-rays, etc. by including information memory cells in three or more independent groups respectively and forming a test memory cell. CONSTITUTION:Horizontal parity bits (a), vertical parity bits (b) and lower right parity bits (c) are formed for 16 data bits arranged on a 4X4 matrix. The horizontal and vertical parity bits (a), (b) are the test information of horizontal and vertical bit groups and the lower right parity bits (c) are the test information of the bit group (a) in the lower right direction. When an one-bit error is generated in the 16 data bits on the matrix, the three bit groups are compared with respective parity bits to detect the one-bit error and a two-bit error can be also detected and corrected. |
