| 摘要 |
PURPOSE:To improve the overall trouble detecting rate and resolution ability of a check circuit by defining all wrong bits '1' as the modulo value when a trouble is detected. CONSTITUTION:A modulo-3 register 501 inputs 2-bit data D=[d1, d2] and a strobe signal STB and outputs 2-bit data E=[e1, e2]. For instance, if the STB is inputted with D=[0, 1] when the output E=[1, 0] is satisfied before input of the STB, the output E is changed to [0, 1] from [1, 0]. Under such conditions, if the STB is inputted with D=[0, 0] satisfied, the output E is changed to [0, 0] from [0, 1]. However the state [1, 1] is kept regardless of the value of D when the original state of the output E is equal to [1, 1]. Therefore the output E is fixed at [1, 1] after input of the STB if D=[1, 1] or E=[1, 1] is satisfied and a fact that a circuit preceding a modulo-W circuit has a trouble since [1, 1] shows originally the wrong data as the value of the modulo-3. |
