| 摘要 |
PURPOSE:To improve error correcting ability even when the number of erasers is three, by providing a register for storing the position of the 3rd eraser. CONSTITUTION:When there are three erasers, position information on the 3rd eraser is stored in an alphak register 23. The details of the three erasers are as shown in a table and when the number of empty erasers epsilone is three, syndromes S0 and S1 are 0 and data is outputted as it is. When the number of empty erasures is two, S0=el and S1=elalphal (l: i, j, or k); when the output of a driving circuit 15 is compared by a comparing circuit 25 with the outputs of an alphai register 6, alphaj register 7, and alphak register 23, they are often coincident and a coincidence signal appears at an output terminal 26. In this case, the coincident alpha is a main eraser epsilonT and its error extent is outputted as the syndrome S0 to an output terminal 18, thereby making a correction. When there is one or no empty eraser, deletion processing is carried out. |
